Cocaine downregulates beta-adrenergic receptors in pregnant sheep myometrium

Academic Article

Abstract

  • 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 beta2-adrenergic antagonist ICI 118,551. We found that cocaine (10-6 to 10-4 mol/L), but not benzoylecgonine, downregulated both beta1- and beta2-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. Copyright © 1996 Elsevier Science Inc. All rights reserved.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Author List

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

  • 119
  • End Page

  • 123
  • Volume

  • 10
  • Issue

  • 2