Development of tolerance to the excitatory effect of morphine and cross-tolerance to the inhibitory action of β-endorphin in the isolated rat vas deferens

J. Pablo Huidobro-Toro, H. Miranda, F. Huidobro

Resultado de la investigación: Article

5 Citas (Scopus)

Resumen

In the isolated rat vas deferens, morphine caused an increase in the neuromuscular twitch evoked by electrical stimulation. In rats chronically treated with morphine, the concentration of the opiate required to cause a 50% increase in the twitch was about 3 times larger than needed to elicit the same response in vasa from rats treated with a placebo. The simultaneous administration of naloxone plus morphine partially antagonized tolerance development by about 22%. Morphine tolerance was extended to other opiate- like alkaloids such as etonitazene and a derivative of azidomorphine (CAM). In contrast to the effects of morphine, β-endorphin inhibited neuromuscular transmission. Vasa from rats chronically treated with morphine were about 10 times less sensitive to the inhibitory effect of β-endorphin as compared to paired placebo treated controls. Chronic naloxone treatment in conjuction with morphine significantly reduced the cross-opiate tolerance by 66%. Present results suggest that morphine may interact at two different sites in the nerve terminals of the rat vas deferens.

Idioma originalEnglish
Páginas (desde-hasta)773-779
Número de páginas7
PublicaciónLife Sciences
Volumen28
N.º7
DOI
EstadoPublished - 16 feb 1981

Huella dactilar

Endorphins
Vas Deferens
Morphine
Rats
Opiate Alkaloids
Naloxone
Placebos
Computer aided manufacturing
Alkaloids
Electric Stimulation
Derivatives

ASJC Scopus subject areas

  • Pharmacology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)
  • Medicine(all)

Citar esto

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title = "Development of tolerance to the excitatory effect of morphine and cross-tolerance to the inhibitory action of β-endorphin in the isolated rat vas deferens",
abstract = "In the isolated rat vas deferens, morphine caused an increase in the neuromuscular twitch evoked by electrical stimulation. In rats chronically treated with morphine, the concentration of the opiate required to cause a 50{\%} increase in the twitch was about 3 times larger than needed to elicit the same response in vasa from rats treated with a placebo. The simultaneous administration of naloxone plus morphine partially antagonized tolerance development by about 22{\%}. Morphine tolerance was extended to other opiate- like alkaloids such as etonitazene and a derivative of azidomorphine (CAM). In contrast to the effects of morphine, β-endorphin inhibited neuromuscular transmission. Vasa from rats chronically treated with morphine were about 10 times less sensitive to the inhibitory effect of β-endorphin as compared to paired placebo treated controls. Chronic naloxone treatment in conjuction with morphine significantly reduced the cross-opiate tolerance by 66{\%}. Present results suggest that morphine may interact at two different sites in the nerve terminals of the rat vas deferens.",
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Development of tolerance to the excitatory effect of morphine and cross-tolerance to the inhibitory action of β-endorphin in the isolated rat vas deferens. / Pablo Huidobro-Toro, J.; Miranda, H.; Huidobro, F.

En: Life Sciences, Vol. 28, N.º 7, 16.02.1981, p. 773-779.

Resultado de la investigación: Article

TY - JOUR

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AU - Miranda, H.

AU - Huidobro, F.

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N2 - In the isolated rat vas deferens, morphine caused an increase in the neuromuscular twitch evoked by electrical stimulation. In rats chronically treated with morphine, the concentration of the opiate required to cause a 50% increase in the twitch was about 3 times larger than needed to elicit the same response in vasa from rats treated with a placebo. The simultaneous administration of naloxone plus morphine partially antagonized tolerance development by about 22%. Morphine tolerance was extended to other opiate- like alkaloids such as etonitazene and a derivative of azidomorphine (CAM). In contrast to the effects of morphine, β-endorphin inhibited neuromuscular transmission. Vasa from rats chronically treated with morphine were about 10 times less sensitive to the inhibitory effect of β-endorphin as compared to paired placebo treated controls. Chronic naloxone treatment in conjuction with morphine significantly reduced the cross-opiate tolerance by 66%. Present results suggest that morphine may interact at two different sites in the nerve terminals of the rat vas deferens.

AB - In the isolated rat vas deferens, morphine caused an increase in the neuromuscular twitch evoked by electrical stimulation. In rats chronically treated with morphine, the concentration of the opiate required to cause a 50% increase in the twitch was about 3 times larger than needed to elicit the same response in vasa from rats treated with a placebo. The simultaneous administration of naloxone plus morphine partially antagonized tolerance development by about 22%. Morphine tolerance was extended to other opiate- like alkaloids such as etonitazene and a derivative of azidomorphine (CAM). In contrast to the effects of morphine, β-endorphin inhibited neuromuscular transmission. Vasa from rats chronically treated with morphine were about 10 times less sensitive to the inhibitory effect of β-endorphin as compared to paired placebo treated controls. Chronic naloxone treatment in conjuction with morphine significantly reduced the cross-opiate tolerance by 66%. Present results suggest that morphine may interact at two different sites in the nerve terminals of the rat vas deferens.

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