T. Durbin, L. Rosenthal, K. Mcarthur
Jun 1, 1982
Citations
0
Influential Citations
57
Citations
Quality indicators
Journal
Gastroenterology
Abstract
Abstract The effects of clonidine and lidamidine on ion transport in the intestine of the rabbit were determined. In the ileum both clonidine (10 −6 M) and lidamidine (10 −3 M) (a) decreased the short circuit current (−1.9 ± 0.3 and −2.0 ± 0.4 μEq/h · cm 2 , respectively) and potential difference; (b) increased net sodium absorption (2.0 ± 0.6 and 1.8 ± 0.4 μEq/ h · cm 2 ) and chloride absorption (3.4 ± 0.5 and 3.4 ± 0.6 μEq/h · cm 2 ); and (c) increased tissue conductance (8.7 ± 1.7 and 10.0 ± 1.6 mmho/cm 2 ). The increase in net sodium and chloride absorption was primarily due to an increase in mucosal-to-serosal movement of the ions and a decrease in serosal-tomucosal movement of chloride. The action of clonidine on the short circuit current was quantitatively similar to the action of epinephrine. Both were readily reversed by yohimbine, a specific α 2 -adrenergic antagonist. Further, methoxamine, an α 1 -adrenergic agonist has no effect on the short circuit current up to the concentration of 10 −5 M; and prazosin, an α 1 -adrenergic antagonist, did not affect the change of the short circuit current induced by epinephrine. The results indicate the presence of α 2 -adrenergic receptors on the intestine and suggest that α 2 -adrenergic stimulation may account for the effect of epinephrine on ion transport. Lidamidine was studied because it is structurally related to clonidine and has many similar actions. Yohimbine transiently reversed the effect of lidamidine. α 1 -Adrenergic or dopaminergic antagonists did not reverse the efect of lidamidine, suggesting that it may affect α 2 -adrenergic receptors. The results indicate that both clonidine and lidamidine stimulate electrolyte absorption and may be clinically useful.