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author:("luck, Janos")
1.  The Biological Effect of Contralateral Forepaw Stimulation in Rat Focal Cerebral Ischemia: A Multispectral Optical Imaging Study 
Our group has already published the possible neuroprotective effect of contralateral forepaw stimulation in temporary focal ischemia in a study. However, the background is still unclear. In the present study we investigated the possible mechanism by monitoring focal ischemia with multispectral [laser speckle, imaging of intrinsic signals (OIS)] imaging. Sprague–Dawley rats were prepared using 1.2% isoflurane anesthesia. The middle cerebral artery was occluded by photothrombosis (4 mW) and the common carotid artery was ligated permanently. Physiological variables were constantly monitored during the experiment. A 6 × 6 mm area centered 3 mm posterior and 4 mm lateral to Bregma was thinned for laser speckle and OIS imaging. Nine circular regions of interests (0.3 mm in diameter) were evenly spaced on the speckle contrast image for the analysis of peri-infarct flow transients, blood flow, and metabolic changes. Both the sham (n = 7) and forepaw-stimulated animals (n = 7) underwent neurological examinations 24 h after ischemia at which point all animals were sacrificed and the infarct size was determined by triphenyltetrazolium chloride. The physiological variables were in normal range and the experimental protocol did not cause significant differences between groups. Both the neurological scores (sham: 3.6 ± 1.7, stimulated: 4.3 ± 1.4) and the infarct volume (sham: 124 ± 39 mm3, stimulated: 147 ± 47 mm3) did not show significant differences between groups. The forepaw stimulation did not increase the intra-ischemic flow neither over the penumbral or the peri-ischemic area. However, the hemoglobin transients related metabolic load (CMRO2) was significantly lower (p < 0.001) while the averaged number of hyperemic flow transients were significantly (p = 0.013) higher in the forepaw (sham: 3.5 ± 2.2, stimulated: 7.0 ± 2.3) stimulated animals.
PMCID: PMC2922941  PMID: 20725601
optical imaging; focal cerebral ischemia; forepaw stimulation; middle cerebral artery occlusion; photothrombosis; speckle contrast; OIS; flow transients
2.  Acute functional recovery of cerebral blood flow after forebrain ischemia in rat 
After complete cerebral ischemia, the postischemic blood flow response to functional activation is severely attenuated for several hours. However, little is known about the spatial and temporal extent of the blood flow response in the acute postischemic period after incomplete cerebral ischemia. To investigate the relative cerebral blood flow (rCBF) response in the somatosensory cortex of rat to controlled vibrissae stimulation after transient incomplete ischemia (15-min bilateral common carotid artery occlusion + hypotension), we employed laser speckle imaging combined with statistical parametric mapping. We found that the ischemic insult had a significant impact on the baseline blood flow (P < 0.005) and the activation area in response to functional stimulation was significantly reduced after ischemia (P < 0.005). The maximum rCBF response in the activation area determined from the statistical analysis did not change significantly up to 3 h after ischemia (P > 0.1). However, the time when rCBF response reached its maximum was significantly delayed (P < 0.0001) from 2.4 ± 0.2 secs before ischemia to 3.6 ± 0.1 secs at 20 mins into reperfusion (P < 0.001); the delay was reduced gradually to 2.9 ± 0.2 secs after 3 h, which was still significantly greater than that observed before the insult (P = 0.04).
PMCID: PMC2771551  PMID: 18382471
cerebral blood flow; cerebral ischemia; functional activation; functional recovery; laser speckle imaging; statistical parametric map
3.  Alpha-chloralose is a Suitable Anesthetic for Chronic Focal Cerebral Ischemia Studies in the Rat: A comparative study 
Brain research  2007;1191:157-167.
α–chloralose is widely used as an anesthetic in studies of the cerebrovasculature because it provides robust metabolic and hemodynamic responses to functional stimulation. However, there have been no controlled studies of focal ischemia in the rat under α–chloralose anesthesia. Artificially ventilated rats were prepared using 1.2−1.5 % isoflurane anesthesia for filament occlusion of the right middle cerebral artery (MCA), and anesthesia was either switched to α–chloralose (60 mg/kg bolus, 30 mg/kg/hr; n=10) or was maintained on 1% isoflurane (n=10). Following temporary MCA occlusion EEG was monitored from a screw electrode and changes in cerebral blood flow (rCBF) measured with a laser Doppler probe placed over the ischemic cortex. This study shows that α–chloralose is a safe anesthetic for ischemia studies and provides excellent survival. Compared with isoflurane, the cortical and total infarct volumes are larger in the α–chloralose anesthetized animals, while the functional outcome at 72 hours is similar. The total duration of peri-infarct flow transients (PIFTs) is also significantly longer in α–chloralose anesthetized animals. The average amplitude of the flow transients showed a good correlation with the extent of edema in all animals as did the total duration of non-convulsive seizures (NCS) in the α–chloralose anesthetized animals.
PMCID: PMC2266075  PMID: 18096143
α–chloralose; edema; focal ischemia; isoflurane; non-convulsive seizures; peri-infarct flow transients

Results 1-3 (3)