Pharmacological characterization of an opioid receptor in the ciliate Tetrahymena.
J Eukaryot Microbiol
; 40(6): 800-4, 1993.
Article
em En
| MEDLINE
| ID: mdl-7904878
ABSTRACT
A pharmacological characterization has been performed of the opioid receptor involved in modulation of phagocytosis in the protozoan ciliate Tetrahymena. Studies on inhibition of phagocytosis by mammalian prototypic opioid agonists revealed that morphine and beta-endorphin have the highest intrinsic activity, whereas all the other opioids tested can only be considered partial agonists. However, morphine (a mu-receptor agonist) is twice as potent as beta-endorphin (a delta-receptor agonist). Furthermore, the sensitivity for the opioid antagonist naloxone, determined in the presence of morphine and beta-endorphin, is very similar to the sensitivity exhibited by mammalian tissues rich in mu-opioid receptors. We suggest that the opioid receptor coupled to phagocytosis in Tetrahymena is mu-like in some of its pharmacological characteristics and may serve as a model system for studies on opioid receptor function and evolution.
Buscar no Google
Base de dados:
MEDLINE
Assunto principal:
Fagocitose
/
Tetrahymena
/
Receptores Opioides
/
Entorpecentes
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
1993
Tipo de documento:
Article