Effects of natriuretic peptides on intracavernous pressure and blood pressure in conscious rats

Introduction. Natriuretic peptides activate particulate guanylyl cyclases and have been shown to induce penile erection in rats, rabbits, and humans. Aim. We investigated the effects of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) on intracavernous pressure (ICP) and systemic blood pressure (BP) in conscious, free-moving rats. Methods. ICP and BP were measured in male Sprague-Dawley rats after catheters were inserted into the crus corpus cavernosum and carotid artery, respectively. Naturiuretic peptides were given by intravenous bolus (3, 10, and 30 nmol/kg) or continous (0.1 and 1 nmol/kg/minute) administration. Main Outcome Measures. The number of animals with increasesin ICP were determined. Amplitudes and durations of ICP responses and changes in BP were also evaluated. Results. More animals had multiple transient increases of ICp in response to ANP and BNP than to CNP. The increases in ICP were transient and appeared to be an all or none response. ANP and BNP decreased BP more than CNP, especially with bolus administration. Conclusions. These findings show that in rats, erectile responses can be intiated by ANP, BNP and less effectively, by CNP. ANP and BNP have a high affinity for the natriuretic peptide receptor-A, suggesting that this receptoris involved in the responses.