Effect of chronic opioid treatment on phagocytosis in Tetrahymena.
Neuropeptides
; 16(3): 115-20, 1990 Jul.
Article
em En
| MEDLINE
| ID: mdl-2082199
ABSTRACT
Opioid inhibition of phagocytosis in the protozoan ciliate Tetrahymena is antagonized by naloxone and this antagonism can be surmounted by increasing agonist concentration, which suggests a receptor-mediated mechanism. Desensitization of the opioid effect is time dependent in addition to concentration dependent. Chronic exposure to opioids results in the development of tolerance to the inhibitory effect of the agonists, and withdrawal of the latter results in a decrease in phagocytic capacity, which suggests that a state akin to dependence has been developed in these cells. Naloxone appears to behave as a partial agonist in tolerant cells, and there seems to exist cross-tolerance to mu and delta agonists.
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Base de dados:
MEDLINE
Assunto principal:
Fagocitose
/
Tetrahymena
/
Encefalina Metionina
/
Morfina
Limite:
Animals
Idioma:
En
Ano de publicação:
1990
Tipo de documento:
Article