A series of pyridinyltetrahydropyridine derivatives was synthesized and evaluated as adrenoceptor and tetrabenazine antagonists. 4-(3-Fluoro-2-pyridinyl)-1, 2, 5, 6- tetrahydropyridine proved to be the most potent and selective cyp-adrenoceptor antagonist of the series as measured in vitro by displacement of [3H] clonidine and [3H] prazosin from membrane binding sites of calf cerebral cortex and by antagonism of the effects of ...