Acute delta9-tetrahydrocannabinol exposure facilitates quinpirole-induced hyperlocomotion.
The endogenous cannabinoid system works as a feedback signal controlling dopamine-induced facilitation of motor behaviors. The present study explored whether a single acute stimulation of CB1 cannabinoid receptors with (-)-Delta9-tetrahydrocannabinol (THC, 5 mg kg(-1) i.p.) results in modifications in the sensitivity to the acute behavioral effects of the dopamine D2/D3 receptor agonist quinpirole (0.025, 0.25 and 1 mg kg(-1), s.c.) 24 h after THC administration. Cannabinoid pretreatment increased the sensitivity to quinpirole-induced hyperlocomotion 24 h after its administration. The data indicated that THC induced a desensitization of cannabinoid receptors, as revealed by a reduction in CB1 receptor-agonist induced GTP-gamma-S incorporation in striatal membranes. These results might be relevant for understanding the effect of cannabinoid exposure in dopamine-related neuropsychiatric disorders.
Gorriti
Miguel Angel
MA
Instituto Universitario de Drogodependencias, Departamento de Psicobiología, Facultad de Psicología, Universidad Complutense de Madrid, Spain.
Ferrer
Belén
B
del Arco
Ignacio
I
Bermúdez-Silva
Francisco Javier
FJ
de Diego
Yolanda
Y
Fernandez-Espejo
Emilio
E
Navarro
Miguel
M
Rodríguez de Fonseca
Fernando
F
D000818:Animals; D004305:Dose-Response Relationship, Drug; D013759:Dronabinol / Q000008:administration & dosage*; D004357:Drug Synergism; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D019257:Quinpirole / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists / Q000502:physiology
D043884:Receptor, Cannabinoid, CB1; D019257:Quinpirole; D013759:Dronabinol