Skip to main content
Catecholamine Stimulation of Ion Transport in the Toad Urinary Bladder
Biochimica et Biophysica Acta (BBA) - Biomembranes (1988)
  • Carl L. Thurman, University of Northern Iowa
  • J. T. Higgins, The Medical College of Ohio
We have observed that serosal catecholamines increase the amplitude of the short-circuit current (Isc) in the toad urinary bladder by as much as 450%. Chemical sympathectomy with 106 M 6-hydroxydopamine and the sympathomimetic effects of 10−5 M tyramine indicate a reservoir of amines in the serosal stroma of the tissue. The urinary epithelium from the toad responds to six adrenoceptor agonists: (−)-epinephrine, (−)-norepinephrine, (−)-phenylephrine, clonidine, methoxamine and oxymetazoline. The α2-adrenoceptor agonist clonidine is most potent for stimulatingIsc. Some agonists were found to diminish Isc. Apparently this is related to a simultaneous increase in the transepithelial flux of both chloride and sodium. The Iscresponse to the catecholamines is also inhibited by several adrenoceptor antagonists. The α2-adrenoceptor antagonist yohimbine is more effective than the α1-antagonist prazosin for blocking the stimulation of epithelial transport. As a result of these studies, we have tentatively classified the serosal adrenoceptor of the toad urinary bladder asα2.
  • Catecholamine,
  • Short circuit current,
  • Epithelial transport,
  • α2-Adrenoceptor,
  • Sodium ion transport,
  • Chloride ion transport
Publication Date
November 3, 1988
Citation Information
Carl L. Thurman and J. T. Higgins. "Catecholamine Stimulation of Ion Transport in the Toad Urinary Bladder" Biochimica et Biophysica Acta (BBA) - Biomembranes Vol. 945 Iss. 1 (1988) p. 81 - 91
Available at: