Cardiac actions of central but not peripheral urotensin II are prevented by β-adrenoceptor blockade

Abstract

Urotensin II (UII) is a highly conserved peptide that has potent cardiovascular actions following central and systemic administration. To determine whether the cardiovascular actions of UII are mediated via β-adrenoceptors, we examined the effect of intravenous (IV) propranolol on the responses to intracerebroventricular (ICV) and IV administration of UII in conscious sheep. Sheep were surgically instrumented with ICV guide tubes and flow probes or cardiac sympathetic nerve recording electrodes. ICV UII (0.2 nmol/kg over 1 h) caused prolonged increases in heart rate (HR; 33 ± 11 beats/min; P < 0.01), dF/dt (581 ± 83 L/min/s; P < 0.001) and cardiac output (2.3 ± 0.4 L/min; P < 0.001), accompa..