Influence of bromocriptine on the pressor responses to afferent nervous stimulation

The effects of intravenous bromocriptine were studied on the systolic pressor responses elicited by stimulation of afferent nerves (vagus, saphenous and superior laryngeal nerves) in urethane anaesthetized dogs. Bromocriptine alone decreased these pressor responses. Pretreatment with sulpiride failed to modify the depressor action of bromocriptine on the pressor responses to vagal stimulation. In contrast, sulpiride prevented bromocriptine-induced decrease in the pressor responses elicited by saphenous or laryngeal activation. These data confirm the potential antihypertensive properties of bromocriptine and show that this effect is only partly due to an activation of prejunctional dopaminergic receptors. They suggest that the mechanism of the antihypertensive action of bromocriptine may vary according to the level of blood pressure, the kind of arterial hypertension and the species.