COCAINE DOWN-REGULATES BETA-ADRENERGIC RECEPTORS IN PREGNANT SHEEP MYOMETRIUM

Citation
Fl. Wang et al., COCAINE DOWN-REGULATES BETA-ADRENERGIC RECEPTORS IN PREGNANT SHEEP MYOMETRIUM, Reproductive toxicology, 10(2), 1996, pp. 119-123
Citations number
13
Categorie Soggetti
Reproductive Biology",Toxicology
Journal title
ISSN journal
08906238
Volume
10
Issue
2
Year of publication
1996
Pages
119 - 123
Database
ISI
SICI code
0890-6238(1996)10:2<119:CDBRIP>2.0.ZU;2-J
Abstract
Cocaine abuse is associated with premature labor, Although cocaine is known to competitively inhibit beta-adrenergic receptor binding, cocai ne's effect on receptor downregulation is uncertain, This study was de signed to determine the in vitro effect of cocaine on downregulation o f beta-adrenergic receptors in pregnant myometrium. Pregnant sheep myo metrium was incubated with either cocaine, isoproterenol, or a cocaine metabolite, benzoylecgonine. Membrane fractions were assayed for beta -adrenergic receptors using (I-125)-cyanopindolol and the beta(2)-adre nergic antagonist ICI 118,551. We found that cocaine (10(-6) to 10(-4) mol/L), but not benzoylecgonine, downregulated both beta(1)- and beta (2)-adrenergic receptors, but did not further augment receptor downreg ulation by isoproterenol. The 46% decrease in beta-adrenergic receptor s seen after exposure to cocaine was similar to the 53% decrease seen after isoproterenol, We hypothesize downregulation of beta-adrenergic receptors by cocaine may play a role in the association of cocaine abu se with premature labor.