Cardiovascular effects produced by microinjection of calcitonin gene-related peptide into the rat central amygdaloid nucleus

Abstract Recent studies have provided evidence for a dense localization of calcitonin gene-related peptide (CGRP) and its receptors within the central amygdaloid nucleus (Ce) in rat brain. Since this nucleus has been thought to play a role in central cardiovascular regulation, the present study examined the cardiovascular effects subsequent to the microinjection of CGRP into the Ce. Doses of 50–500 pmol of CGRP produced a significant elevation of 11–15% in systolic, diastolic and mean arterial pressures. Heart rate was significantly elevated by 16–18% by these doses of CGRP. The time course of the effects of CGRP revealed that onset of action occurred after 15–20 min, peak effects were seen at approximately 30–40 min after onset and the effects of the peptide usually lasted for at least 2 hr, after which time BP and HR values returned to baseline. The present study demonstrates that CGRP produces significant increases in both BP and HR when pmol doses of the peptide are injected into the Ce. It is suggested that in the Ce, CGRP plays a neuromodulatory role in cardiovascular function.