Neural contribution to the effect of glucagon-like peptide-1-(7-36) amide on arterial blood pressure in rats

This study was designed to determine the contribution of the central nervou s system (CNS) to the effects of glucagon-like peptide-1-(7-36) amide (tGLP -1) on arterial blood pressure and heart rate in rats. Accordingly, intrace rebroventricular administration of the peptide produced an increase in card iovascular parameters, which was blocked by previous administration of exen din-(9-39) through the same route, but not when it was intravenously inject ed. Intravenous administration of tGLP-1 produced a significant increase in arterial blood pressure and heart rate, which was blocked by the previous intracerebroventricular or intravenous administration of exendin-(9-39). Bi lateral vagotomy blocked the stimulating effect of intracerebroventricular tGLP-1 administration on arterial blood pressure and heart rate. Also, bila teral vagotomy prevented the blocking effect of intracerebroventricular but not of intravenous exendin-(9-39) on cardiovascular parameters after intra venous administration of tGLP-1. These findings suggest that the action of tGLP-1 on cardiovascular parameters is under a dual control generated in th e CNS and in peripheral structures and that the neural information emerging in the brain is transmitted to the periphery through the vagus nerve.