Structure-activity requirements for hypotension and alpha-adrenergic receptor blockade by analogues of atropine
European Journal of Pharmacology
E H CantorS Spector
The hypotensive action of various antimuscarinic compounds structurally related to atropine was studied in conscious, unanesthetized rats. The alpha-adrenolytic activity of these agents was assessed both in vivo (blockade of norepinephrine-induced pressor response) and in vitro (displacement of [3H]WB-4101 binding). Benztropine, homatropine and hyoscyamine caused hypotension and produced alpha-adrenergic receptor blockade similar to atropine. Other analogues were either inactive (atroscine, scopolamine, tropic acid and tropine) or evoked nonspecific changes in blood pressure and lacked alpha-adrenolytic activity (benactyzine, eucatropine, methylatropine, methylhomatropine and methylscopolamine). Based on these data, we propose the following structure-activity relationship for hypotension and alpha-adrenolytic activity: (a) the tropine moiety is inactive unless it is attached to another group by an ester linkage, (b) chemical modification of the tropine moiety, including quaternization, decreases potency, (c) the d-stereoisomer appears to be more potent than the corresponding 1-form.
Adrenergic receptor trafficking is an active physiological process where adrenergic receptors are relocated from one region of the cell to another or from one type of cell to another. Discover the latest research on adrenergic receptor trafficking here.