Effect of Alpha and Beta blockers on the hydrosmotic response of the isolated skin of the toad Bufo arenarum to adrenaline, vasopressin and angiostensin II

Abstract

Effect of Alpha and Beta blockers on the hydrosmotic response of the isolated skin of the toad Bufo arenarum to adrenaline, vasopressin and angiostensin II?. The hydrosmotiec effect of epinephrine (E), vasopressin (VP) and angiotensin II (AT) were measured gravimetrically in untreated and phentolamine ?or propranolol? treated toad skin. The existence of autoinhibition for high doses of E, previously reported to exist in frog skin, was confirmed in toad skin in the present series of experiments. Beta-adrenergic blocking agents significantly inhibit the hydrosmotic effect of submaximal doses of E, but it was found that, in contrast to previous reports, phentolamine also blocks such effects. No explanation exists as yet for this observation. Neither alpha-nor beta-blockers affect the response to VP or AT, showing that different receptors exist in toad skin for catecholamine and peptide hormones.