Specific features of Soma plant are implict from various references in Rigveda enabling its identity as ephedra. Its juice is an energizer – cum – euphoriant contrary to the intoxicant sura. Sura is beer prepared from barely malt. Soma is the juice of ephedra rich in ephedrine which is antisomnalent. At least one use of soma has never been substituted, as the drink of longevity for a newly born child.
Ephedra was a source of anti-fatigue drink. In later period it became a drink of immortality and longevity. The use of Soma as the first drink of a newly born child is mentioned in Rigveda. The author identifies the Soma of Rigveda with the Ephedra and established its use in ancient Rome and also highlights here its continuity among Zorostrains.
Soma was originally Sauma as the Sanskrit form of the Avesta name Haoma. It is a loan word from the Chinese term, Hao-Ma, fire coloured hempior fibrous items like hemp and also coloured yellow with a tinge of brown. The Aryans as hunters took its juice as anti-fatigue drink. It was extolled as panacea and even as drink of longevity. The plant and its stalks were crushed between stones to produce juice. There arose different fractions and these have been given in a regular chart here.
The morphology of confirmed projection neurons in the dorsal lateral geniculate nucleus (dLGN) of the rat was examined by filling these cells retrogradely with biotinylated dextran amine (BDA) injected into the visual cortex. BDA-labeled projection neurons varied widely in the shape and size of their cell somas, with mean cross-sectional areas ranging from 60–340 µm2. Labeled projection neurons supported 7–55 dendrites that spanned up to 300 µm in length and formed dendritic arbors with cross-sectional areas of up to 7.0×104 µm2. Primary dendrites emerged from cell somas in three broad patterns. In some dLGN projection neurons, primary dendrites arise from the cell soma at two poles spaced approximately 180° apart. In other projection neurons, dendrites emerge principally from one side of the cell soma, while in a third group of projection neurons primary dendrites emerge from the entire perimeter of the cell soma. Based on these three distinct patterns in the distribution of primary dendrites from cell somas, we have grouped dLGN projection neurons into three classes: bipolar cells, basket cells and radial cells, respectively. The appendages seen on dendrites also can be grouped into three classes according to differences in their structure. Short “tufted” appendages arise mainly from the distal branches of dendrites; “spine-like” appendages, fine stalks with ovoid heads, typically are seen along the middle segments of dendrites; and “grape-like” appendages, short stalks that terminate in a cluster of ovoid bulbs, appear most often along the proximal segments of secondary dendrites of neurons with medium or large cell somas. While morphologically diverse dLGN projection neurons are intermingled uniformly throughout the nucleus, the caudal pole of the dLGN contains more small projection neurons of all classes than the rostral pole.
In China the antecedent of alchemy is represented by the god of longevity emerging from the peach. The first synthetic drug, Kim-Yeh, red colloidal gold, signified gold-cum -herbal juice. Kim-Yeh=Kimiya (Arabic) =chemeia (Greek). Translated this gave Chrusozomion=Gold Ferment, specifying the drug. Rasayana was translated as Chumeia, herbal juice-incorporate and signified the art alchemy. Chemeia was Chinese and Chumeia, Indian. Originally each signified both, a drug of longevity and the art, alchemy. Finally the art of making red gold was misunderstood as the art of making gold itself
To study sequential changes in retinal ganglion cell (RGC) morphology in mice after optic nerve crush and after induction of experimental glaucoma.
Nerve crush or experimental glaucoma was induced in mice that selectively express yellow fluorescent protein (YFP) in RGCs. Mice were euthanized 1, 4, and 9 days after crush and 1, 3, and 6 weeks after induction of glaucoma by bead injection. All YFP-RGCs were identified in retinal whole mounts. Then confocal images of randomly selected RGCs were quantified for somal fluorescence brightness, soma size, neurite outgrowth, and dendritic complexity (Sholl analysis).
By 9 days after crush, 98% of RGC axons died and YFP-RGCs decreased by 64%. After 6 weeks of glaucoma, 31% of axons died, but there was no loss of YFP-RGC bodies. All crush retinas combined had significant decreases in neurite outgrowth parameters (P ≤ 0.036, generalized estimating equation [GEE] model) and dendritic complexity was lower than controls (P = 0.017, GEE model). There was no change in RGC soma area after crush. In combined glaucoma data, the RGC soma area was larger than control (P = 0.04, GEE model). At 3 weeks, glaucoma RGCs had significantly larger values for dendritic structure and complexity than controls (P = 0.044, GEE model), but no statistical difference was found at 6 weeks.
After nerve crush, RGCs and axons died rapidly, and dendritic structure decreased moderately in remaining RGCs. Glaucoma caused an increase in RGC dendrite structure and soma size at 3 weeks.
Retinal ganglion cell morphology after optic nerve crush and experimental glaucoma.
Automated and accurate localization and morphometry of somas in 3D neuron images is essential for quantitative studies of neural networks in the brain. However, previous methods are limited in obtaining the location and surface morphology of somas with variable size and uneven staining in large-scale 3D neuron images. In this work, we proposed a method for automated soma locating in large-scale 3D neuron images that contain relatively sparse soma distributions. This method involves three steps: (i) deblocking the image with overlap between adjacent sub-stacks; (ii) locating the somas in each small sub-stack using multi-scale morphological close and adaptive thresholds; and (iii) fusion of the repeatedly located somas in all sub-stacks. We also describe a new method for the accurate detection of the surface morphology of somas containing hollowness; this was achieved by improving the classical Rayburst Sampling with a new gradient-based criteria. Three 3D neuron image stacks of different sizes were used to quantitatively validate our methods. For the soma localization algorithm, the average recall and precision were greater than 93% and 96%, respectively. For the soma surface detection algorithm, the overlap of the volumes created by automatic detection of soma surfaces and manually segmenting soma volumes was more than 84% for 89% of all correctly detected somas. Our method for locating somas can reveal the soma distributions in large-scale neural networks more efficiently. The method for soma surface detection will serve as a valuable tool for systematic studies of neuron types based on neuron structure.
Ephedra-containing dietary supplements are consumed to improve sports performace, but may carry risks of cardiac and neurological adverse events. Little is known of their use by young athletes. Our aim was to determine the prevalence and patterns of ephedra use among high school athletes. An anonymous survey was performed in Rochester, Minnesota on high school athletes who participated in fall sports during 2003-04. Parental consent was obtained for athletes under age 18 years. Surveys were distributed at preparticipation examinations and in- school survey stations. The response rate to the survey was 68.2%, or 311 respondents out of a possible 456 with consent (or 26% of all 1197 athletes eligible prior to the consent process). Seven of 311 (2.3%) respondents used dietary supplements containing ephedra. Only one of seven users (14.3%) knew that the supplements they used contained ephedra. Ephedra use was more common in boys (five) than girls (two). Ephedra use was only found in 17 and 18-year-olds. The most common sports among ephedra users were football, track and field, and weightlifting. This study suggests that Ephedra use was infrequent among the young athletes in this population. However, ephedra users were generally unaware that the dietary supplements they consumed contained ephedra. Users were more likely to participate in football, track and field, and weightlifting. Ephedra users were likely to obtain supplements from their peers, and were largely uninformed of the content of their supplements.
Key PointsEphedra is an herbal stimulant used as an ergogenic aide.Adolescent ephedra users most commonly obtain it from their friends.Adolescent athletes are likely to take ephedra unknowningly.
Ephedrine; sports; supplements; performance enhancement, ergogenic
The authors recently reported a retrograde double-labeling technique in the mouse retina. In this study, the specificity and reliability of this method for labeling retinal ganglion cells was further examined and confirmed. With use of this labeling technique and a confocal microscope, the authors revealed 16 morphologic subtypes of displaced ganglion cells in the mammalian retina for the first time.
To examine the specificity and reliability of a retrograde double-labeling technique that was recently established for identification of retinal ganglion cells (GCs) and to characterize the morphology of displaced (d)GCs (dGs).
A mixture of the gap-junction–impermeable dye Lucifer yellow (LY) and the permeable dye neurobiotin (NB) was applied to the optic nerve stump for retrograde labeling of GCs and the cells coupled with them. A confocal microscope was adopted for morphologic observation.
GCs were identified by LY labeling, and they were all clearly labeled by NB. Cells coupled to GCs contained a weak NB signal but no LY. LY and NB revealed axon bundles, somas and dendrites of GCs. The retrogradely identified GCs numbered approximately 50,000 per retina, and they constituted 44% of the total neurons in the ganglion cell layer (GCL). Somas of retrogradely identified dGs were usually negative for glycine, ChAT (choline acetyltransferase), bNOS (brain-type nitric oxidase), GAD (glutamate decarboxylase), and glial markers, and occasionally, they were weakly GABA-positive. dGs averaged 760 per retina and composed 1.7% of total GCs. Sixteen morphologic subtypes of dGs were encountered, three of which were distinct from known GCs. dGs sent dendrites to either sublaminas of the IPL, mostly sublamina a.
The retrograde labeling is reliable for identification of GCs. dGs participate in ON and OFF light pathways but favor the OFF pathway. ChAT, bNOS, glycine, and GAD remain reliable AC markers in the GCL. GCs may couple to GABAergic ACs, and the gap junctions likely pass NB and GABA.
We previously demonstrated that human embryonic mesenchymal cells derived from the palate (HEMP cells) retain alkaline phosphatase (ALP) content and capacity for collagen synthesis after long-term culture, and their growth is markedly stimulated by epidermal growth factor (EGF). There was a dramatic decrease in ALP content and capacity to synthesize collagen in HEMP cells (HEMP-RV cells) persistently infected with rubella virus (RV). EGF increased ALP activity and decreased collagen synthesis in HEMP cells, whereas EGF showed no effect on these activities in HEMP-RV cells. Growth of HEMP-RV cells was slightly reduced compared with that of HEMP cells. EGF stimulated growth of HEMP cells and to a lesser extent of HEMP-RV cells. Binding of 125I-EGF to cell-surface receptors in HEMP-RV cells was, to our surprise, twice as much as that in HEMP cells. However, internalization of bound 125I-EGF in HEMP-RV cells was profoundly diminished. Thus, persistent RV infection causes not only changes in HEMP cell growth and differentiation but a decrease in or loss of HEMP cell responsiveness to EGF. The effects of persistent RV infection on palatal cell differentiation as well as growth may be responsible for the pathogenesis of congenital rubella. Furthermore, since HEMP cells appear to be closely related to osteoblasts, these results suggest a mechanism for RV-induced osseous abnormalities manifested in congenital rubella patients.
The present investigation continues a previous study in which the soma-dendrite system of sensory neurons was excited by stretch deformation of the peripheral dendrite portions. Recording was done with intracellular leads which were inserted into the cell soma while the neuron was activated orthodromically or antidromically. The analysis was also extended to axon conduction. Crayfish, Procambarus alleni (Faxon) and Orconectes virilis (Hagen), were used. 1. The size and time course of action potentials recorded from the soma-dendrite complex vary greatly with the level of the cell's membrane potential. The latter can be changed over a wide range by stretch deformation which sets up a "generator potential" in the distal portions of the dendrites. If a cell is at its resting unstretched equilibrium potential, antidromic stimulation through the axon causes an impulse which normally overshoots the resting potential and decays into an afternegativity of 15 to 20 msec. duration. The postspike negativity is not followed by an appreciable hyperpolarization (positive) phase. If the membrane potential is reduced to a new steady level a postspike positivity appears and increases linearly over a depolarization range of 12 to 20 mv. in various cells. At those levels the firing threshold of the cell for orthodromic discharges is generally reached. 2. The safety factor for conduction between axon and cell soma is reduced under three unrelated conditions, (a) During the recovery period (2 to 3 msec.) immediately following an impulse which has conducted fully over the cell soma, a second impulse may be delayed, may invade the soma partially, or may be blocked completely. (b) If progressive depolarization is produced by stretch, it leads to a reduction of impulse height and eventually to complete block of antidromic soma invasion, resembling cathodal block, (c) In some cells, when the normal membrane potential is within several millivolts of the relaxed resting state, an antidromic impulse may be blocked and may set up within the soma a local potential only. The local potential can sum with a second one or it may sum with potential changes set up in the dendrites, leading to complete invasion of the soma. Such antidromic invasion block can always be relieved by appropriate stretch which shifts the membrane potential out of the "blocking range" nearer to the soma firing level. During the afterpositivity of an impulse in a stretched cell the membrane potential may fall below or near the blocking range. During that period another impulse may be delayed or blocked. 3. Information regarding activity and conduction in dendrites has been obtained indirectly, mainly by analyzing the generator action under various conditions of stretch. The following conclusions have been reached: The large dendrite branches have similar properties to the cell body from which they arise and carry the same kind of impulses. In the finer distal filaments of even lightly depolarized dendrites, however, no axon type all-or-none conduction occurs since the generator potential persists to a varying degree during antidromic invasion of the cell. With the membrane potential at its resting level the dendrite terminals contribute to the prolonged impulse afternegativity of the soma. 4. Action potentials in impaled axons and in cell bodies have been compared. It is thought that normally the over-all duration of axon impulses is shorter. Local activity during reduction of the safety margin for conduction was studied. 5. An analysis was made of high frequency grouped discharges which occasionally arise in cells. They differ in many essential aspects from the regular discharges set up by the generator action. It is proposed that grouped discharges occur only when invasion of dendrites is not synchronous, due to a delay in excitation spread between soma and dendrites. Each impulse in a group is assumed to be caused by an impulse in at least one of the large dendrite branches. Depolarization of dendrites abolishes the grouped activity by facilitating invasion of the large dendrite branches.
Axonal arbors of principal neurons form the backbone of neuronal networks in the mammalian cortex. Three-dimensional reconstructions of complete axonal trees are invaluable for quantitative analysis and modeling. However, digital data are still sparse due to labor intensity of reconstructing these complex structures. We augmented conventional tracing techniques with computational approaches to reconstruct fully labeled axonal morphologies. We digitized the axons of three rat hippocampal pyramidal cells intracellularly filled in-vivo from different CA3 sub-regions: two from areas CA3b and CA3c, respectively, toward the septal pole, and one from the posterior/ventral area (CA3pv) near the temporal pole. The reconstruction system was validated by comparing the morphology of the CA3c neuron with that traced from the same cell by a different operator on a standard commercial setup. Morphometric analysis revealed substantial differences among neurons. Total length ranged from 200mm (CA3b) to 500mm (CA3c), and axonal branching complexity peaked between 1mm (CA3b and CA3pv) and 2mm (CA3c) of Euclidean distance from the soma. Length distribution was analyzed among sub-regions (CA3a,b,c and CA1a,b,c), cytoarchitectonic layers, and longitudinal extent within a three-dimensional template of the rat hippocampus. The CA3b axon extended thrice more collaterals within CA3 than into CA1. On the contrary, the CA3c projection was double into CA1 than within CA3. Moreover, the CA3b axon extension was equal between strata oriens and radiatum, while the CA3c axon displayed an oriens/radiatum ratio of 1:6. The axonal distribution of the CA3pv neuron was intermediate between those of the CA3b and CA3c neurons both relative to sub-regions and layers, with uniform collateral presence across CA3/CA1 and moderate preponderance of radiatum over oriens. In contrast with the dramatic sub-region and layer differences, the axon longitudinal spread around the soma was similar for the three neurons. To fully characterize the axonal diversity of CA3 principal neurons will require higher-throughput reconstruction systems beyond the three-fold speed-up of the method adopted here.
Axonal arbors; CA3c; CA3b; digital morphology; hippocampus; principal neuron; Schaffer collateral
Ayurveda, the Indian holistic healthcare system encompasses traditional medicines with a principle of creating harmony and maintaining balance within the natural rhythms of the body. Rasayana is one of the branches of Ayurveda frequently used as rejuvenant therapy to overcome many discomforts and prevent diseases. It has been reported that rasayanas have immunomodulatory, antioxidant and antitumor functions. However, the genotoxic potential of many rasayanas remains to be evaluated. The present study was undertaken to assess the role of Brahma rasayana(BR) on genotoxicity in vivo in a mouse test system. The older mice (9 months) were orally fed with rasayana for 8 weeks. The treated groups showed no signs of dose-dependent toxicity at the dosage levels tested. The body weight loss/gain and feed consumption were unaffected at tested doses. Furthermore, sperm abnormalities and chromosomal aberrations were insignificant in the treatment group when compared to controls. However, there was a marginal increase in sperm count in the BR treated animals. These findings clearly indicate that there are no observed adverse genotoxic effects elicited by BR in experimental animals such as mice.
Aging; Brahma rasayana; chromosomal aberrations; genotoxicity; sperm abnormalities
To investigate the clinical usefulness of the Schedule for Oral-Motor Assessment (SOMA) in children with dysphagia by comparing findings of SOMA with those of the videofluoroscopic swallowing study (VFSS).
Both SOMA and VFSS were performed in 33 children with dysphagia (21 boys and 12 girls; mean age 17.3±12.1 months) who were referred for oropharyngeal evaluation. Ratings of oral-motor functions indicated by SOMA were based upon the cutting score of each specific texture of food (puree, semi-solids, solids, cracker, liquid-bottle, and liquid-cup). Abnormalities of either the oral phase, or the pharyngeal phase as indicated by VFSS were assessed by a physician and a speech-language pathologist.
There was significant consistency between the findings of SOMA and the oral phase evaluation by VFSS (Kappa=0.419, p=0.023). SOMA reached 87.5% sensitivity, 66.6% specificity, and 95.4% positive predictive value when compared with the oral phase of the VFSS. We were able to evaluate oral-motor function by using SOMA in 6 children who were unable to complete the oral phase evaluation by VFSS, due to fear and crying during the study. The findings of SOMA failed to show any consistency with the pharyngeal phase evaluation by VFSS (Kappa=-0.105, p=0.509).
These results suggest that SOMA is a reliable method for evaluation of oral-motor function in children with dysphagia. In particular, SOMA is recommended for children that were unable to complete the oral phase evaluation by VFSS due to poor cooperation.
Dysphagia; Oral-motor dysfunction; Schedule for Oral-Motor Assessment (SOMA); Videofluoroscopic swallowing study (VFSS)
CA1 pyramidal neurons receive hundreds of synaptic inputs at different distances from the soma. Distance-dependent synaptic scaling enables distal and proximal synapses to influence the somatic membrane equally, a phenomenon called “synaptic democracy”. How this is established is unclear. The backpropagating action potential (BAP) is hypothesised to provide distance-dependent information to synapses, allowing synaptic strengths to scale accordingly. Experimental measurements show that a BAP evoked by current injection at the soma causes calcium currents in the apical shaft whose amplitudes decay with distance from the soma. However, in vivo action potentials are not induced by somatic current injection but by synaptic inputs along the dendrites, which creates a different excitable state of the dendrites. Due to technical limitations, it is not possible to study experimentally whether distance information can also be provided by synaptically-evoked BAPs. Therefore we adapted a realistic morphological and electrophysiological model to measure BAP-induced voltage and calcium signals in spines after Schaffer collateral synapse stimulation. We show that peak calcium concentration is highly correlated with soma-synapse distance under a number of physiologically-realistic suprathreshold stimulation regimes and for a range of dendritic morphologies. Peak calcium levels also predicted the attenuation of the EPSP across the dendritic tree. Furthermore, we show that peak calcium can be used to set up a synaptic democracy in a homeostatic manner, whereby synapses regulate their synaptic strength on the basis of the difference between peak calcium and a uniform target value. We conclude that information derived from synaptically-generated BAPs can indicate synapse location and can subsequently be utilised to implement a synaptic democracy.
Neurons receive information from other neurons via hundreds of contacts (synapses) spread across their dendritic branches. Input signals from synapses propagate along a dendrite to the cell body (soma), where the neuron decides whether or not to produce an action potential. Signals that travel further decay more. Were all synapses equally strong, a synapse far from the soma would have less influence on the decision than a synapse close by. However, neurons in the hippocampus, which are involved in learning and memory, have synapses far from the soma that are stronger than those close by, so that all synapses have an equal voice (“synaptic democracy”). But how can a synapse “know” how far it is from the soma? Using a computational model of a hippocampal neuron, we show that the action potential, which propagates from the soma back into the dendrites, contains information with which synapses can estimate their somatic distance. Specifically, the calcium concentration at the synapse, which is modulated by the backpropagating action potential, decreases with distance from the soma. We show that when the strength of a synapse is adapted in a self-organising manner based on calcium concentration, synaptic democracy is obtained.
The aim of the present study was to investigate the hypolipidemic and antioxidant potential of ephedra extractions in diet-induced hyperlipidemic mice. Mice were fed a diet high in fat to establish the hyperlipidemic model. A total of 48 mice were randomly divided into six groups, which included the normal control, model control, positive control, ephedra alkaloid, ephedra polysaccharide and ephedra non-alkaloid groups. Intragastric administration of the respective treatments was provided continuously for four weeks and the body weight was recorded weekly. The total levels of cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and malondialdehyde (MDA), and the activity levels of superoxide dismutase (SOD), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum were recorded. In addition, changes in liver morphology and organ coefficients (ratio of organ to body weight) were evaluated, while the acute toxicity reactions of ephedra extractions were investigated using the modified Spearman-Karber method. Compared with the mice in the model control group, the weight, liver coefficient, serum levels of TC, TG and MDA, and activities of ALT and AST were significantly lower (P<0.05) in the mice in the ephedra non-alkaloid group. However, the level of HDL-C and the activity of SOD were markedly higher (P<0.05). Fatty degeneration of the liver in the ephedra alkaloid and non-alkaloid groups was notably improved compared with the model control group. The mean lethal dose (LD50) of ephedra alkaloids was 610 mg/kg, and the maximum tolerated dose of oral ephedra non-alkaloids in the mice was 367.5-fold larger than the clinical dosage in humans. In conclusion, ephedra non-alkaloids have therapeutic potential for the treatment of hyperlipidemia, since they are able to improve lipid metabolism and are relatively safe for use under the maximum tolerated dose.
ephedra alkaloids; ephedra polysaccharides; ephedra non-alkaloids; hyperlipidemia; acute toxicity
Globally, cataract is the leading cause of blindness and impaired vision. Cataract surgery is an attractive treatment option but it remains unavailable in sufficient quantity for the vast majority of the world population living in areas without access to specialized health care. Reducing blindness from cataract requires solutions that can be applied outside operating theatres. Cataract is a protein conformational disease characterized by accumulation of light absorbing, fluorescent and scattering protein aggregates. The aim of the study was to investigate whether these compounds were susceptible to photobleaching by a non-invasive procedure and whether this would lead to optical rejuvenation of the lens.
Nine human donor lenses were treated with an 800 nm infra-red femtosecond pulsed laser in a treatment zone measuring 1×1×0.52 mm. After laser treatment the age-induced yellow discoloration of the lens was markedly reduced and the transmission of light was increased corresponding to an optical rejuvenation of 3 to 7 years.
The results demonstrate that the age-induced yellowing of the human lens can be bleached by a non-invasive procedure based on femtosecond laser photolysis. Cataract is a disease associated with old age. At the current technological stage, lens aging is delayed but with a treatment covering the entire lens volume complete optical rejuvenation is expected. Thus, femtosecond photolysis has the potential clinical value of replacing invasive cataract surgery by a non-invasive treatment modality that can be placed in mobile units, thus breaking down many of the barriers impeding access to treatment in remote and poor regions of the world.
The stretch receptor organs of Alexandrowicz in lobster and crayfish possess sensory neurons which have their cell bodies in the periphery. The cell bodies send dendrites into a fine nearby muscle strand and at the opposite pole they give rise to an axon running to the central nervous system. Mechanisms of excitation between dendrites, cell soma, and axon have been studied in completely isolated receptor structures with the cell components under visual observation. Two sensory neuron types were investigated, those which adapt rapidly to stretch, the fast cells, and those which adapt slowly, the slow cells. 1. Potentials recorded from the cell body of the neurons with intracellular leads gave resting potentials of 70 to 80 mv. and action potentials which in fresh preparations exceeded the resting potentials by about 10 to 20 mv. In some experiments chymotrypsin or trypsin was used to make cell impalement easier. They did not appreciably alter resting or action potentials. 2. It has been shown that normally excitation starts in the distal portion of dendrites which are depolarized by stretch deformation. The changed potential within the dendritic terminals can persist for the duration of stretch and is called the generator potential. Secondarily, by electrotonic spread, the generator potential reduces the resting potential of the nearby cell soma. This excitation spread between dendrites and soma is seen best during subthreshold excitation by relatively small stretches of normal cells. It is also seen during the whole range of receptor stretch in neurons in which nerve conduction has been blocked by an anesthetic. The electrotonic changes in the cells are graded, reflecting the magnitude and rate of rise of stretch, and presumably the changing levels of the generator potential. Thus in the present neurons the resting potential and the excitability level of the cell soma can be set and controlled over a wide range by local events within the dendrites. 3. Whenever stretch reduces the resting membrane potential, measured in the relaxed state in the cell body, by 8 to 12 mv. in slow cells and by 17 to 22 mv. in fast cells, conducted impulses are initiated. It is thought that in slow cells conducted impulses are initiated in the dendrites while in fast cells they arise in the cell body or near to it. In fresh preparations the speed of stretch does not appreciably influence the membrane threshold for discharges, while during developing fatigue the firing level is higher when extension is gradual. 4. Some of the specific neuron characteristics are: Fast receptor cells have a relatively high threshold to stretch. During prolonged stretch the depolarization of the cell soma is not well maintained, presumably due to a decline in the generator potential, resulting in cessation of discharges in less than a minute. This appears to be the basis of the relatively rapid adaptation. A residual subthreshold depolarization can persist for many minutes of stretch. Slow cells which resemble the sensory fibers of vertebrate spindles are excited by weak stretch. Their discharge rate remains remarkably constant for long periods. It is concluded that, once threshold excitation is reached, the generator potential within slow cell dendrites is well maintained for the duration of stretch. Possible reasons for differences in discharge properties between fast and slow cells are discussed. 5. If stretch of receptor cells is gradually continued above threshold, the discharge frequency first increases over a considerable range without an appreciable change in the firing level for discharges. Beyond that range the membrane threshold for conducted responses of the cell soma rises, the impulses become smaller, and partial conduction in the soma-axon boundary region occurs. At a critical depolarization level which may be maintained for many minutes, all conduction ceases. These overstretch phenomena are reversible and resemble cathodal block. 6. The following general scheme of excitation is proposed: stretch deformation of dendritic terminals → generator potential → electrotonic spread toward the cell soma (prepotential) → dendrite-soma impulse → axon impulse. 7. Following release of stretch a transient hyperpolarization of slow receptor cells was seen. This off effect is influenced by the speed of relaxation. 8. Membrane potential changes recorded in the cell bodies serve as very sensitive detectors of activity within the receptor muscle bundles, indicating the extent and time course of contractile events.
Ayurveda, the traditional Indian system of medicine has given great emphasis to the promotion of health. Rasayana is one of the eight branches of Ayurveda which refers to rejuvenant therapy. It has been reported that rasayanas have immuno-modulatory, antioxidant and antitumor functions, however, the genotoxic potential and modulation of DNA repair of many rasayanas have not been evaluated.
The present study assessed the role of Brahmarasayana (BR) on Ethyl methanesulfonate (EMS)-and Methyl methanesulfonate (MMS)-induced genotoxicity and DNA repair in in vivo mouse test system. The mice were orally fed with BR (5 g or 8 mg / day) for two months and 24 h later EMS or MMS was given intraperitoneally. The genotoxicity was analyzed by chromosomal aberrations, sperm count, and sperm abnormalities.
The results have revealed that BR did not induce significant chromosomal aberrations when compared to that of the control animals (p >0.05). On the other hand, the frequencies of chromosomal aberrations induced by EMS (240 mg / kg body weight) or MMS (125 mg / kg body weight) were significantly higher (p<0.05) to that of the control group. The treatment of BR for 60 days and single dose of EMS or MMS on day 61, resulted in significant (p <0.05) reduction in the frequency of chromosomal aberrations in comparison to EMS or MMS treatment alone, indicating a protective effect of BR. Constitutive base excision repair capacity was also increased in BR treated animals.
The effect of BR, as it relates to antioxidant activity was not evident in liver tissue however rasayana treatment was observed to increase constitutive DNA base excision repair and reduce clastogenicity. Whilst, the molecular mechanisms of such repair need further exploration, this is the first report to demonstrate these effects and provides further evidence for the role of brahmarasayana in the possible improvement of quality of life.
DNA damage and repair; Anti clastogenicity; Rasayana
The fine structure of a physiologically identified motor neuron in the segmental ganglion of the leech central nervous system and the morphology of synapses on it were studied after injection of the fluorescent dye Procion yellow as a marker. The injected cell and its processes within the neuropil were located in thick or thin sections with fluorescence optics after initial fixation with glutaraldehyde and brief treatment with osmium tetroxide. The same or adjacent thin sections could then be examined in the electron microscope. Comparison with uninjected cells showed that the general features of the injected cell are retained although some organelles are distorted. The main features of the geometry of this neuron are the same from animal to animal: a single large process runs from the soma through the neuropil to bifurcate and enter the contralateral roots. Within the neuropil the main process gives off long branches (up to 150 µ), but these are greatly outnumbered by short branches and spines, one or a few microns in length, which were not appreciated in previous light microscope studies after injection of Procion yellow. Serial thin sections of selected areas along the main process within the neuropil showed that there are synapses on most of the shorter branches and spines; occasional synaptic contacts were also made on the main process itself and on longer branches. At least two morphologically distinct types of synapse could be recognized. A minimum estimate of the total number of synapses on the motor cell is 300, based on their occurrence in reconstructed segments.
Bracts of female cones of extant gymnosperm Ephedra (Joint fir) are either colorful and fleshy (section Ephedra), or dry-winged and membranous (section Alatae), or dry and coriaceous (section Asarca), which have played a crucial role in long-distance seed dispersal that is responsible for a wide distribution of the genus in semiarid and arid areas of Eurasia, North Africa, North America, and South America. Recent molecular systematic studies on Ephedra have suggested that the fleshy bracts in character evolution may be plesiomorphic relative to the dry, membranous and coriaceous bracts. However, little is known about when the fleshy bracts of Ephedra have made their debut in the geological past. Herein, we describe a novel, fleshy bract-bearing female cone macrofossil from the Early Cretaceous (ca. 120—125 Ma) Yixian Formation in Liaoning, northeastern China. This cone bears three ellipsoid seeds subtended by only one whorl of fleshy bracts. Each seed has a thin outer envelope and an inner integument that extends upward and passes through the opening of the outer envelope, forming a thin and straight micropylar tube. Such a syndrome shows the closest similarity to an extant triovulate species Ephedra intermedia in the section Ephedra, but the latter bears a whorl of terminal fertile bracts and more than one whorl of inferior sterile bracts, and a thick outer envelope. Hence, we establish a new fossil species Ephedra carnosa. Our discovery provides the first direct macrofossil evidence for the previous molecular systematics of Ephedra, implying that the origin of fleshy bracts in Ephedra should not have been later than that of the membranous and coriaceous bracts by at least the Early Cretaceous.
This article traces the history of the Khat which is an intoxicant and also a sexual depressant. The author establishes that its origion is Abyssinia and it is brought to Arabia where it is commonly used even by Muslims. If Khat is consumed in excess it may impair the health but moderate quantity is beneficial.