Effects of terbutaline on peripheral vascular resistance and arterial compliance

In a double blind, randomized placebo-controlled crossover study we characterized how terbutaline affects the mean and short-term fluctuations of peripheral vascular resistance and arterial compliance. The study was carried out in six young and healthy male subjects in the supine and upright positions by recording continuously electrocardiography and finger arterial blood pressure. On average, large intravenous terbutaline doses reduce maximally by 50% the mean systolic-diastolic pressure decay time (windkessel time), by 30% the mean vascular resistance, and by 20% the mean arterial compliance. Terbutaline reduces differently the beat-to-beat variability of peripheral vascular resistance and arterial compliance. The effects can be explained by beta-adrenoceptor activation that mediates smooth muscle relaxation in small resistance arteries and large conduit arteries. Differences between vascular resistance and compliance lowering actions could be explained by differences in the beta-adrenoceptor-mediated vascular relaxation and sympathetically mediated vascular contraction between small and large arteries.