Imidazoline Receptors A New Concept in Central Regulation of the Arterial Blood Pressure

Clonidine-like antihypertensive substances bind to nonadrenergic imidazoline specific sites within the nucleus reticularis lateralis (NRL), their medullary privileged site of action. Rilmenidine, a new central antihypertensive agent, was tested in the anesthetized rabbit. For the same hypotensive effect, cumulative doses given intracisternally proved 50 times more active than of those given systemically. Idazoxan, an α 2 -adrenergic antagonist structurally related to the imidazolines, given centrally as pretreatment proved more potent in preventing the hypotensive effects than the same molar dose of yohimbine