Effects of Chronic Alcohol Exposure on the Modulation of Ischemia-Induced Glutamate Release via Cannabinoid Receptors in the Dorsal Hippocampus.
BACKGROUND
Chronic alcohol consumption is a critical contributing factor to ischemic stroke, as it enhances ischemia-induced glutamate release, leading to more severe excitotoxicity and brain damage. But the neural mechanisms underlying this phenomenon are poorly understood.


METHODS
We evaluated the effects of chronic alcohol exposure on the modulation of ischemia-induced glutamate release via CB1 and CB2 cannabinoid receptors during middle cerebral artery occlusion, using in vivo microdialysis coupled with high-performance liquid chromatography, in alcohol-naïve rats or rats after 1 or 30 days of withdrawal from chronic ethanol intake (6% v/v for 14 days).


RESULTS
Intra-dorsal hippocampus (DH) infusions of ACEA or JWH133, selective CB1 or CB2 receptor agonists, respectively, decreased glutamate release in the DH in alcohol-naïve rats in a dose-dependent manner. Such an effect was reversed by co-infusions of SR141716A or AM630, selective CB1 or CB2 receptor antagonists, respectively. After 30 days, but not 1 day of withdrawal, ischemia induced an enhancement in glutamate release in the DH, as compared with non-alcohol-treated control group. Intra-DH infusions of JWH133, but not ACEA, inhibited ischemia-induced glutamate release in the DH after 30 days of withdrawal. Finally, 1 day of withdrawal did not alter the protein level of CB1 or CB2 receptors in the DH, as compared to non-alcohol-treated control rats. Whereas 30 days of withdrawal robustly decreased the protein level of CB1 receptors, but failed to alter the protein level of CB2 receptors, in the DH, as compared to non-alcohol-treated control rats.


CONCLUSIONS
Together, these findings suggest that loss of expression/function of CB1 receptors, but not CB2 receptors in the DH, is correlated with the enhancement of ischemia-induced glutamate release after prolonged alcohol withdrawal.
Liaocheng Third People's Hospital, Liaocheng, Shandong, China.
Lei
L
Zheng
Liaocheng Third People's Hospital, Liaocheng, Shandong, China.
Xiaoda
X
Wu
Liaocheng Third People's Hospital, Liaocheng, Shandong, China.
Xiao
X
Dong
Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China.
Xinli
X
Ding
Liaocheng Third People's Hospital, Liaocheng, Shandong, China.
Cunfeng
C
Song
D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology; D002186:Cannabinoids / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage* / Q000494:pharmacology*; D018698:Glutamic Acid / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D020244:Infarction, Middle Cerebral Artery; D007511:Ischemia / Q000378:metabolism*; D008297:Male; D010880:Piperidines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D043885:Receptor, Cannabinoid, CB2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000077285:Rimonabant
D001095:Arachidonic Acids; D002186:Cannabinoids; D007211:Indoles; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; C119325:arachidonyl-2-chloroethylamide; D000431:Ethanol; D018698:Glutamic Acid; D000077285:Rimonabant; C432747:1,1-dimethylbutyl-1-deoxy-Delta(9)-THC; C094023:iodopravadoline
Alcohol; Cannabinoid Receptor; Glutamate; Hippocampus; Ischemia