Effect of chronic opioid treatment on phagocytosis in Tetrahymena.
Enviado por Walter Silva el
Título | Effect of chronic opioid treatment on phagocytosis in Tetrahymena. |
Publication Type | Journal Article |
Year of Publication | 1990 |
Autores | Salaman, A, Roman, M, Renaud, FL, Silva, WI |
Journal | Neuropeptides |
Volume | 16 |
Issue | 3 |
Pagination | 115-20 |
Date Published | 1990 Jul |
ISSN | 0143-4179 |
Palabras clave | Animals, Drug Tolerance, Enkephalin, Methionine, Morphine, Naloxone, Phagocytosis, Tetrahymena, Time Factors |
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. |
Alternate Journal | Neuropeptides |
PubMed ID | 2082199 |
Grant List | RR-08102 / RR / NCRR NIH HHS / United States |