Prolonged glucocorticoid treatment decreases cannabinoid CB1 receptor density in the hippocampus
✍ Scribed by Matthew N. Hill; Erica J. Carrier; W.-S. Vanessa Ho; Leyu Shi; Sachin Patel; Boris B. Gorzalka; Cecilia J. Hillard
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 195 KB
- Volume
- 18
- Category
- Article
- ISSN
- 1050-9631
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✦ Synopsis
Experimental studies indicate a bidirectional, functional relationship between glucocorticoids and the endocannabinoid system; however, the effects of repeated glucocorticoid treatment on the endocannabinoid system have not been examined. In this study, we treated male rats with either a single dose or a 21-day course of treatment with corticosterone (20 mg/kg) and measured hippocampal cannabinoid CB 1 receptor expression and endocannabinoid content. The 21-day, but not the single, administration of corticosterone significantly reduced both the binding site density and amount of protein of the hippocampal cannabinoid CB 1 receptor without affecting affinity for the CB 1 receptor agonist, [ 3 H]CP55940. With regard to hippocampal endocannabinoid content, acute corticosterone treatment resulted in a significant reduction in anandamide but did not affect 2-arachidonylglycerol, while repeated corticosterone treatment did not alter content of either anandamide or 2-arachidonylglycerol. These data support the hypothesis that the cannabinoid CB 1 receptor is under negative regulation by glucocorticoids in the hippocampus, and suggest that hippocampal cannabinoid CB 1 receptor signaling could be reduced under conditions associated with hypersecretion of glucocorticoids, such as chronic stress. V V