Cannabinoid-induced delayed gastric emptying is selectively increased upon intermittent administration in the rat: role of CB1 receptors
Article first published online: 8 FEB 2011
© 2011 Blackwell Publishing Ltd
Neurogastroenterology & Motility
Volume 23, Issue 5, pages 457–e177, May 2011
How to Cite
Abalo, R., Cabezos, P. A., Vera, G., López-miranda, V., Herradón, E. and Martín-fontelles, M. I. (2011), Cannabinoid-induced delayed gastric emptying is selectively increased upon intermittent administration in the rat: role of CB1 receptors. Neurogastroenterology & Motility, 23: 457–e177. doi: 10.1111/j.1365-2982.2011.01677.x
- Issue published online: 11 APR 2011
- Article first published online: 8 FEB 2011
- Received: 30 July 2010 Accepted for publication: 10 January 2011
- gastrointestinal motility;
- intermittent administration;
Background Cannabinoids acutely administered depress central, cardiovascular and gastrointestinal functions. These effects might be modified upon repeated administration. Compared to the effects induced by daily administration, those induced by intermittent administration are less known. The effect of intermittent treatment with the CB1/CB2 cannabinoid agonist WIN55,212-2 (WIN) was studied in the rat.
Methods Male rats received saline, vehicle or WIN at 0.5 (low-WIN) or 5 (high-WIN) mg kg−1 week−1 for 4 weeks. WIN effects on the central nervous system (cannabinoid tetrad tests), cardiovascular function and gastrointestinal motor function were evaluated after the first and last doses, and, where appropriate, 1 week after the last dose. To determine the involvement of CB1 receptors in the chronic effect of WIN, the CB1 receptor antagonist/inverse agonist AM251 (1 mg kg−1) was used.
Key Results High- (but not low-) WIN induced the four signs of the cannabinoid tetrad, and reduced gastrointestinal motility, but did not alter cardiovascular parameters. Upon chronic intermittent administration, tolerance did not clearly develop to WIN effects. Quite the opposite, depression of gastric emptying was intensified. No effect was long-lasting. Repeated administration of AM251 was more efficacious than single administration to block WIN chronic central effects, but the opposite occurred regarding lower intestinal motility.
Conclusions & Inferences Upon intermittent administration, hypersensitization may develop to some effects (particularly delayed gastric emptying) induced by cannabinoid agonists. CB1 antagonists/inverse agonists may show different efficacy upon repeated or single administration to block cannabinoid-induced central and gastrointestinal effects. Thus, cannabinoid effects are dependent on the pattern of drug administration.