Neurochemical and Neuropharmacological Investigations with Four Ergot Derivatives: Bromocriptine, Dihydroergotoxine, CF 25-397 and CM 29-712

Abstract

Neurochemical and neuropharmacological investigations with four ergot derivatives reveal differential pharmacodynamic effects of these compounds. Bromocriptine and CM 29–712 showed actions typical of postsynaptic dopamine receptor stimulants, in particular in the extrapyramidal system. CM 29–712 proved to be more potent than bromocriptine, with an early onset of action. CF 25–397 and dihydroergotoxine, while not showing all actions typical of central dopamine agonists, appeared to exert some of their effects by means of a stimulation of central serotoninergic sites. In the rat sleep-wakefulness cycle and in reserpine-induced ponto-geniculo-occipital waves in the cat, they mimicked the effects of 5-hydroxytryptophan. In the latter test, CF 25–397 proved to be particularly potent. In addition, bromocriptine, dihydroergotoxine and CM 29–712 showed neurochemical effects consistent with central α-adrenergic blockade or an enhanced impulse flow in central noradrenergic neurons.