Cocaine downregulates beta-adrenergic receptors in pregnant sheep myometrium.

Journal Article

Cocaine abuse is associated with premature labor. Although cocaine is known to competitively inhibit beta-adrenergic receptor binding, cocaine's effect on receptor downregulation is uncertain. This study was designed to determine the in vitro effect of cocaine on downregulation of beta-adrenergic receptors in pregnant myometrium. Pregnant sheep myometrium was incubated with either cocaine, isoproterenol, or a cocaine metabolite, benzoylecgonine. Membrane fractions were assayed for beta-adrenergic receptors using (125I)-cyanopindolol and the beta 2-adrenergic 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 downregulation by isoproterenol. The 46% decrease in beta-adrenergic receptors 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 abuse with premature labor.

Full Text

Duke Authors

Cited Authors

  • Wang, FL; Gauvin, JM; Dombrowski, MP; Smith, YR; Christopher, KA; Hurd, WW

Published Date

  • March 1996

Published In

Volume / Issue

  • 10 / 2

Start / End Page

  • 119 - 123

PubMed ID

  • 8919608

Electronic International Standard Serial Number (EISSN)

  • 1873-1708

International Standard Serial Number (ISSN)

  • 0890-6238

Digital Object Identifier (DOI)

  • 10.1016/0890-6238(95)02053-5

Language

  • eng