Pretreatment with electroacupuncture induces rapid tolerance to focal cerebral ischemia through regulation of endocannabinoid system.
OBJECTIVE
Our previous study demonstrated that pretreatment with electroacupuncture (EA) induces rapid tolerance to focal cerebral ischemia. The present study was aimed to investigate the involvement of the endocannabinoid system in the early neuroprotection conferred by EA pretreatment in the animal model of focal cerebral ischemia.


METHODS
Two hours after the end of EA pretreatment, focal cerebral ischemia was induced by middle cerebral artery occlusion for 120 minutes in male Sprague-Dawley rats or male C57BL/6 mice. The neurobehavioral scores, infarction volumes, and neuronal apoptosis were evaluated at 24 hours or 7 days after reperfusion in the presence or absence of AM251 (a selective cannabinoid receptor type 1 [CB1] receptor antagonist) or CB1 short interfering RNA. The expression of CB1 receptor and the content of endocannabinoids in the brains were also investigated.


RESULTS
EA pretreatment reduced infarct size, improved neurological outcome, and inhibited neuronal apoptosis at 24 hours or 7 days after reperfusion. The beneficial effects were abolished by AM251. CB1 knockdown by CB1 short interfering RNA attenuated EA pretreatment-induced neuroprotection. EA pretreatment upregulated the neuronal expression of CB1 receptor in the rat brains and elevated the brain tissue content of the endocannabinoid 2-arachidonylglycerol and N-arach-idonoylethanolamine-anandamide. Pretreatment with 2-arachidonylglycerol and N-arach-idonoylethanolamine-anandamide also reduced infarct size and improved neurological outcome.


CONCLUSIONS
We conclude that pretreatment with EA increases the production of endocannabinoid 2-arachidonylglycerol and N-arach-idonoylethanolamine-anandamide, which elicits protective effects against transient cerebral ischemia through CB1 receptors. These results suggest a novel mechanism of EA pretreatment-induced rapid tolerance to focal cerebral ischemia.
Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China.
Qiang
Q
Wang
Ye
Y
Peng
Shaoyang
S
Chen
Xingchun
X
Gou
Bo
B
Hu
Juan
J
Du
Yan
Y
Lu
Lize
L
Xiong
D015669:Acupuncture Points; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001923:Brain Chemistry / Q000235:genetics / Q000502:physiology; D002545:Brain Ischemia / Q000503:physiopathology* / Q000523:psychology / Q000628:therapy*; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism / Q000502:physiology*; D002544:Cerebral Infarction / Q000473:pathology; D002851:Chromatography, High Pressure Liquid; D015671:Electroacupuncture; D063388:Endocannabinoids; D020287:In Situ Nick-End Labeling; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018696:Neuroprotective Agents / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D043884:Receptor, Cannabinoid, CB1 / Q000187:drug effects / Q000502:physiology
D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D018696:Neuroprotective Agents; D010880:Piperidines; D011720:Pyrazoles; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D043884:Receptor, Cannabinoid, CB1; C103505:AM 251