Pharmacological evaluation of benzotriazole derivatives structurally related to trazodone

Abstract

Thirteen [(aryl/heteroaryl-piperazinyl)alkyl]benzotriazoles were prepared as potential trazodone- and buspirone-like drugs. The synthesized compounds displayed from moderate to good affinity to the serotonin 5-HT1A receptor and only modest or poor affinity to the dopamine D2 receptor, similar to buspirone. The introduction of substituents on the benzotriazole ring did not improve the affinity to the 5-HT1A receptor, compared to the previously described unsubstituted derivatives. In a general pharmacological screening, which concerned only three of these compounds so far (5, 7 and 13), several in vitro and in vivo activities were observed.The guinea pig ileum contractions, induced either electrically or by several agonists, were strongly inhibited; at higher concentrations also the spontaneous tone of the guinea pig trachea was reduced. Compound 13 exhibited good analgesic activity in mice in the formalin-induced algesia and in the writhing test. The same at 30 mg kg−1 p.o. also displayed antihypertensive activity probably related to calcium channel blockade and adrenergic α1 antagonism. In binding assays, 13 showed a IC50=580 nM for displacing [3H]prazosin from α1 receptor.Finally, compound 5 (and, to a minor extent, compound 13) protected mice against potassium cyanide induced hypoxia.