The effect of U-50,488H tolerance-dependence and abstinence on the levels of dynorphin (1-13) in brain regions, spinal cord, pituitary gland and peripheral tissues of the rat.
Brain Res
; 600(1): 151-5, 1993 Jan 08.
Article
em En
| MEDLINE
| ID: mdl-8093675
ABSTRACT
Male Sprague-Dawley rats were rendered tolerant to and physically dependent on U-50,488H, a kappa-opiate agonist, by injecting 25 mg/kg of the drug intraperitoneally twice a day for 4 days. Two sets of rats were used. Rats labeled as tolerant-dependent were injected with U-50,488H (25 mg/kg) 1 h before sacrificing on day 5, whereas the abstinent rats were sacrificed on day 5 without the injection of U-50,488H. Of all the tissues on day 5 without the injection of U-50,488H. Of all the tissues examined, the pituitary gland had the highest level of dynorphin (1-13), whereas the heart had the lowest level. The levels of dynorphin (1-13) increased in the hypothalamus, hippocampus and pons/medulla of U-50,488H tolerant-dependent rats, whereas in abstinent rats the levels of dynorphin (1-13) were elevated only in the midbrain. The levels of dynorphin (1-13) in the pituitary gland of U-50,488H tolerant-dependent or abstinent rats were unchanged. In peripheral tissues, the levels of dynorphin (1-13) in the heart of U-50,488H tolerant-dependent rats were increased. In the abstinent rats they were elevated in the adrenals, spleen, and the heart but were decreased in the kidneys. Compared to morphine tolerant-dependent and abstinent rats, significant differences in the levels of dynorphin (1-13) in tissues of 50,488H tolerant-dependent and abstinent rats were observed and may explain many pharmacological differences in the mu- and kappa-opiate induced tolerance-dependence and abstinence processes.
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Base de dados:
MEDLINE
Assunto principal:
Fragmentos de Peptídeos
/
Hipófise
/
Pirrolidinas
/
Medula Espinal
/
Encéfalo
/
Dinorfinas
/
Analgésicos
Limite:
Animals
Idioma:
En
Ano de publicação:
1993
Tipo de documento:
Article