Moreno M, Lopez-Moreno J A, Rodríguez de Fonseca F, Navarro M
Departamento de Psicobiologia, Facultad de Psicologia, Instituto Universitario de Drogodependencias, Universidad Complutense de Madrid, Spain.
Behav Pharmacol. 2005 Sep;16(5-6):441-6. doi: 10.1097/00008877-200509000-00017.
The present study investigated spontaneous and quinpirole-induced motor responses of in rats, following withdrawal from chronic treatment with the potent cannabinoid agonist HU-210. Withdrawal from chronic HU-210 (20 microg/kg daily, 14 days) produced a decrease in spontaneous activity at 1 and 2 days and enhanced the hyperactivity induced by acute administration of the dopamine D2 agonist quinpirole (0.5 mg/kg) at 4 days after the end of HU-210 treatment. Administration of quinpirole on day 4 of withdrawal from chronic HU-210 enhanced stereotyped responses and induced jumping behaviour. These results suggest that withdrawal from chronic exposure to cannabinoid agonists could induce a time-dependent alteration in dopamine D2 psychomotor function, leading to a behavioural disorganization, comparable to acute psychotic episodes after continuous cannabinoids.
