Inhibition of hippocampal acetylcholine release after acute and repeated Δ9-tetrahydrocannabinol in rats
1998; Elsevier BV; Volume: 809; Issue: 1 Linguagem: Inglês
10.1016/s0006-8993(98)00738-0
ISSN1872-6240
AutoresGiovanna Carta, Felice Nava, G L Gessa,
Tópico(s)Sleep and Wakefulness Research
ResumoThe effects of acute and repeated administration of Δ9-tetrahydrocannabinol (Δ9-THC), the psychoactive principle of marijuana, on acetylcholine release in the hippocampus was studied in freely moving rats by microdialysis. The acute intraperitoneal (i.p.) administration of Δ9-THC at the doses of 2.5 and 5 mg/kg reduced acetylcholine release by about 25% and 45%, respectively. A dose of 7.5 mg/kg produced no further reduction. Δ9-THC effects were antagonized by the cannabinoid CB1 antagonist SR141716A at the i.p. dose of 1 mg/kg, per se ineffective in modifying acetylcholine concentrations. After a repeated exposure (twice daily for up to seven days) to Δ9-THC (7.5 mg/kg, i.p.) or vehicle (0.3 ml/kg, i.p.), the inhibitory effect of Δ9-THC (2.5 and 5 mg/kg, i.p) on acetylcholine release was not reduced. The results confirm previous observations that cannabinoids inhibit acetylcholine release through cannabinoid CB1 receptors, and indicate that no tolerance to this effects develops after a repeated Δ9-THC administration.
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