Receptor selectivity of icv morphine in the rat cold water tail-flick test.
Drug Alcohol Depend
; 35(3): 197-202, 1994 Jun.
Article
em En
| MEDLINE
| ID: mdl-7956748
ABSTRACT
The cold water tail-flick test in the rat is somewhat unique in that it is sensitive to the analgesic effects of delta- and kappa- in addition to mu-opioid agonists. The present study was designed to test whether a component of morphine-induced analgesia in this test might be mediated by delta- or kappa-opioid receptors. Morphine was administered icv in combination with the non-selective opioid antagonist naloxone (NLX), as well as the mu-, delta- and kappa-selective antagonists, D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr (CTAP), naltrindole (NTI) and norbinaltorphimine (norBNI), respectively. Morphine induced analgesia in a dose related manner. Administration of NLX (1-10 micrograms) or CTAP (1 microgram) antagonized morphine in a competitive fashion. Neither NTI (1-10 micrograms) nor norBNI (0.1 microgram) had any effect on the morphine dose-effect curve. Thus, morphine appeared to be a selective mu agonist in the cold water tail-flick test, at least by the icv route.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Encéfalo
/
Limiar da Dor
/
Receptores Opioides
/
Morfina
Limite:
Animals
Idioma:
En
Revista:
Drug Alcohol Depend
Ano de publicação:
1994
Tipo de documento:
Article