title: Stimulation of cannabinoid receptor agonist 2-arachidonylglycerol by chronic ethanol and its modulation by specific neuromodulators in cerebellar granule neurons.
abstract: In an earlier study, we reported that chronic ethanol (EtOH) stimulates the formation of anandamide in human SK-N-SH cells. In the present study, we investigated the effect of chronic EtOH on the formation of yet another cannabinoid receptor (CB1) agonist, 2-arachidonylglycerol (2-AG), in cerebellar granule neurons (CGNs). The formation of 2-[(3)H]AG without any stimulation was more pronounced in the older cultures than in younger cultures. Exposure of CGNs to EtOH led to a significant increase in the level of 2-[(3)H]AG (P<0.05). Incubation with the anandamidehydrolase inhibitor phenylmethylsulfonyl fluoride and EtOH did result in an additive increase in 2-[(3)H]AG, but did not with E-6-(bromomethylene)tetrahydro-3-(1-naphthelenyl)-2H-pyran-2-one. The formation of 2-[(3)H]AG was enhanced by ionomycin in both the control and EtOH-exposed CGNs, and the ionomycin-stimulated 2-[(3)H]AG synthesis was inhibited by the intracellular chelating agent 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. Further, glutamate increased the formation of 2-[(3)H]AG only in control CGNs. MK-801 inhibited the EtOH-induced 2-[(3)H]AG synthesis, suggesting the participation of intracellular Ca(2+) in EtOH-induced 2-[(3)H]AG synthesis. The dopamine receptor (D2) agonist did not modify the 2-AG synthesis in either the control or EtOH-exposed CGNs. However, the D2 receptor antagonist inhibited the EtOH-induced formation of 2-[(3)H]AG. The EtOH-induced 2-[(3)H]AG formation was inhibited by SR141716A and pertussis toxin, suggesting the CB1 receptor- and Gi/o-protein-mediated regulation of 2-AG. The observed increase in 2-AG level in CGNs is possibly a mechanism for neuronal adaptation to the continuous presence of EtOH. These findings indicate that some of the pharmacological actions of EtOH may involve alterations in the endocannabinoid signaling system.
authors: New York State Psychiatric Institute, Nathan S. Kline Institue for Psychiatric Research, Orangeburg, 10962, USA.
authors: B S
authors: BS
authors: Basavarajappa
authors: M
authors: M
authors: Saito
authors: T B
authors: TB
authors: Cooper
authors: B L
authors: BL
authors: Hungund
mesh_terms: D000818:Animals; D001095:Arachidonic Acids; D002118:Calcium / Q000494:pharmacology; D063385:Cannabinoid Receptor Modulators; D002478:Cells, Cultured; D002531:Cerebellum / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D004305:Dose-Response Relationship, Drug; D063388:Endocannabinoids; D000431:Ethanol / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D005989:Glycerides / Q000096:biosynthesis* / Q000737:chemistry; D009474:Neurons / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000819:agonists* / Q000037:antagonists & inhibitors; D013997:Time Factors; D014316:Tritium
chemical_list: D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D005989:Glycerides; D018377:Neurotransmitter Agents; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D014316:Tritium; D000431:Ethanol; C094503:glyceryl 2-arachidonate; D019204:GTP-Binding Proteins; D002118:Calcium