ABSTRACT
This study is to investigate the effect of gamma-hydroxybutyric acid receptor (GHBR) on focal cerebral ischemia-reperfusion injury in rats and its mechanism. NCS-356 (the agonist of GHBR) and NCS-382 (the antagonist of GHBR) were adopted as the tool medicine. The ripe male Sprague-Dawley rats weighing 240 - 280 g were randomly divided into seven groups: sham operation group (sham), ischemia-reperfusion group (Isc/R), NCS-356 160 microg x kg(-1) group (N1), NCS-356 320 microg x kg(-1) group (N2), NCS-356 640 microg x kg(-1) group (N3), NCS-382 640 microg x kg(-1) + NCS-356 640 microg x kg(-1) group (NCS-382 + N3), and nimodipine (Nim) 600 microg x kg(-1) group. The middle cerebral artery occlusion (MCAO) model referring to Longa's method with modifications was adopted. The effect of GHBR on behavioral consequence of MCAO rats was studied after 2 h of ischemia-reperfusion. After 24 h of ischemia-reperfusion, part of animals were used to measure the cerebral infarction volume by TTC staining; ischemic cortex of another part of animals were used to measure the content of intracellular free calcium by flow cytometry, the tNOS, iNOS activity and the content of NO by spectrophotometric method, the content of cGMP by radioimmunoassay. The neurological function score and infarction volume rate in Isc/R group rats increased significantly than that in sham group; The content of intracellular calcium ([Ca2+]) of cortex neuron and cGMP, the activities of tNOS and iNOS, and the content of NO in Isc/R group were higher than that in sham group obviously (P < 0.01); These consequence we mentioned of N1, N2, N3 and Nim group were lower than that of Isc/R. NCS-382 + N3 group could significantly antagonize the above effect of N3. Thus, NCS-356 has protective effects against ischemia-reperfusion brain injury by activating GHBR. The neuroprotective effect of GHBR is related with decreasing the content of [Ca2+]i, NO, cGMP and tNOS, iNOS activity in MCAO rats.
Subject(s)
Animals , Male , Rats , Benzocycloheptenes , Pharmacology , Calcium , Metabolism , Cerebral Cortex , Metabolism , Cerebral Infarction , Pathology , Cyclic GMP , Metabolism , Infarction, Middle Cerebral Artery , Neuroprotective Agents , Pharmacology , Nitric Oxide , Metabolism , Nitric Oxide Synthase , Metabolism , Nitric Oxide Synthase Type II , Metabolism , Random Allocation , Rats, Sprague-Dawley , Receptors, Cell Surface , Metabolism , Reperfusion Injury , Metabolism , PathologyABSTRACT
<p><b>AIM</b>To investigate the effects of melatonin (MT) on histology and behavioral tests during global cerebral ischemia-reperfusion in gerbils.</p><p><b>METHODS</b>Global cerebral ischemia was induced by occluding the bilateral common carotid arteries for 10 min in gerbils. Three doses of MT were administrated intraperitoneally 30 min prior to the onset of ischemia. Locomotor activity was measured by using the open field method 3 and 7 days after the ischemic episode. T maze test was carried out 4, 5 and 6 days after ischemia to assess the working memory of gerbils. Neuronal damage was assessed in CA1 pyramidal layer of gerbil hippocampus and evaluated 7 days after ischemia.</p><p><b>RESULTS</b>MT significantly reversed the locomotor activity increases, ameliorated learning and working memory deficit, and reduced the extent of CA1 hippocampal pyramidal cells injury after transient global cerebral ischemia in the Mongolian gerbil.</p><p><b>CONCLUSION</b>MT provides significantly protective effect against both histological and behavioral consequences of global cerebral ischemia-reperfusion injury in gerbils.</p>
Subject(s)
Animals , Female , Male , Brain Ischemia , Gerbillinae , Hippocampus , Pathology , Learning , Melatonin , Pharmacology , Therapeutic Uses , Memory , Motor Activity , Neurons , Pathology , Neuroprotective Agents , Pharmacology , Therapeutic Uses , Random Allocation , Reperfusion InjuryABSTRACT
In formalin pain model, the effect of propofol on Fos expression in the spinal cord was examined by means of c -fos oncogene immunohistochemistry and NADPH-d histochemistry. Fos-like immunoreactive (FLI) neurons were mainly found in the ipsilateral dorsal horn after injection of formalin, some of which were FLI/NOS double-labeled neurons. Most of the FLI or FLI/NOS double-labeled neurons were observed in the medial part of lamina and the outer lamina . Before or after injection of formain, i.p. injection of propofol significantly decreased the number of FLI and FLI/NOS double-labeled neurons in all laminae (P<0.05 or P<0.01). By single i.p. injection of propofol or normal saline, few FLI neurons were found in the spinal cord. The results suggest that the antinociceptive function of propofol is possibly involved in the depression of the NOS neurons in the spinal cord.
Subject(s)
Animals , Female , Male , Rats , Formaldehyde , Neurons , Metabolism , Nitric Oxide Synthase , Metabolism , Pain , Metabolism , Propofol , Pharmacology , Proto-Oncogene Proteins c-fos , Rats, Sprague-Dawley , Spinal Cord , MetabolismABSTRACT
Objective To observe the effect of circadian rhythm on hypnotic median effective dose( ED50) of ketamine. Methods Sixty mice were randomly divided into 4 groups which had 15 mice in each group. They were intraperitoneally injected with ketamine at different times of 2 Am,8 Am,2 Pm and 8 Pm, respectively. Righting reflex was recorded and the value of ED50 was measured with sequential experimental method. Results The hypnotic ED50 of ketamine at 2 Am was(54.57?0.82) mg/kg, with 95% confidence limit of ED50 38.06-78.22 mg/kg;ED50 was(49. 27?0. 12) mg/kg at 8 Am, with 95% confidence limit of ED50 40. 21-60. 37 mg/kg;ED50 at 2 Pm was (42.28?0.21) mg/kg, with 95% confidence limit 37.35 - 47 83 mg/kg;and ED50 at 8 Pm was(57.42?0.14) mg/kg, with 95% confidence limit 37.51-73 72 mg/kg,respectively. The ED50 were significant different at 2 Pm and 8 Pm. However, there were no significant difference in ED50 value among other groups. Conclusion The hypnotic effect of ketamine has circadian rhythm - dependent.