Peripheral versus central effect of intravenous moxonidine on rat carotid sinus baroreflex-mediated sympathetic arterial pressure regulation

Moxonidine is a centrally acting antihypertensive agent with a selectivity to I1-imidazoline receptors higher than that to α2-adrenergic receptors. The present study aimed to quantify a peripheral effect of moxonidine on carotid sinus baroreflex-mediated sympathetic arterial pressure (AP) regulation separately from its central effect. In eight anesthetized Wistar rats, changes in efferent sympathetic nerve activity (SNA) and AP in response to a carotid sinus pressure input were compared before and during an intravenous administration of moxonidine (100μgkg−1 bolus followed by a continuous infusion at 200μg·kg−1·h−1). Moxonidine significantly narrowed the range of the AP response (55.3±5.8 to 39.1±6.1mmHg, P