Pharmacological analysis of acute morphine dependence in infant rats: close molecular relationship of head-shaking precipitated by opiate antagonists and cholinergic neurotransmission
Arch. med. res
; 27(2): 139-44, 1996. ilus
Artículo
en Inglés
| LILACS
| ID: lil-200305
Biblioteca responsable:
MX1.1
ABSTRACT
The influence of drugs affecting different neurotransmitter systems on an acute abstinence heanshaking (AHS) model induced by nalorphine or naloxone was studied in 9-day-old rat pups pretreated (3 h before) with morphine (10mg/kg, i.p.). One hour after the injection of nalorphine (10 mg/kg, i.p.) AHS was stopped by a second dose of morphine (10 mg/kg, i.p.) and reinitiated 1 h later by a higher dose of nalorphine (20 mg/kg, i.p.). In other groups AHS was blocked by spiroperidol (0.1 mg/kg, i.p.), clonidine (0.01 mg/kg, i.p.) or scopolamine (50 mg/kg, i.p.). In these groups a second injection of nalorphine did not reinitiate AHS. In dose-effect curve experiments the AHS induced by naloxone or nalorphine was significantly reduced by previous injections of scopolamine, spiroperidol, metergoline or phentolamine in the corresponding groups. Scopolamine was the only antagonist which displaced the AHS dose-effect curves to the right without affecting the maximal response. Since no common receptors exist for a direct competitive interaction between opiate antagonists and scopolamine, these experiments suggest that a direct molecular relationship exists between the tissue concentration of nalorphine (or naloxone) and the endogenous ACh release during abstinence. Thus, the AHS model in 9-day-old rats clearly differentiates specific from non-specific blockade of the abstinence syndrome, and confirms a distinct or primary role of cholinergic neurotransmission in morphine abstinence
Buscar en Google
Colección:
Bases de datos internacionales
Base de datos:
LILACS
Asunto principal:
Parasimpaticomiméticos
/
Escopolamina
/
Ratas Wistar
/
Neurotransmisores
/
Morfina
/
Dependencia de Morfina
Límite:
Animales
Idioma:
Inglés
Revista:
Arch. med. res
Asunto de la revista:
Medicina
Año:
1996
Tipo del documento:
Artículo