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Regional vasodilator actions of calcitonin gene-related peptide in conscious SHR
Insights
Calcitonin gene-related peptide (CGRP) is a potent vasodilator in spontaneously hypertensive rats (SHR). This peptide significantly lowers blood pressure and vascular resistance, suggesting a role in cardiovascular regulation.
Area of Science:
- Cardiovascular Physiology
- Pharmacology
Background:
- Hypertension is a significant risk factor for cardiovascular disease.
- The role of specific peptides in regulating blood pressure in hypertensive models requires further elucidation.
Purpose of the Study:
- To investigate the regional hemodynamic effects of Calcitonin Gene-Related Peptide (CGRP) in conscious, unrestrained spontaneously hypertensive rats (SHR).
- To determine if CGRP exhibits regional selectivity in its vasodilator effects.
Main Methods:
- Chronically instrumented conscious rats (SHR) with pulsed Doppler flow probes.
- Continuous measurement of renal, mesenteric, and hindquarter blood flow.
- Intravenous administration of CGRP at varying doses (0.1-5 micrograms/kg).
Main Results:
- CGRP induced a dose-dependent decrease in mean arterial pressure (up to -48 mmHg) and a marked tachycardia (up to 143 b/min).
- The depressor effect of CGRP was sustained for 3-5 minutes.
- CGRP significantly reduced vascular resistance across renal, mesenteric, and hindquarter vascular beds without regional selectivity.
Conclusions:
- CGRP acts as a potent vasodilator in conscious SHR.
- These findings suggest CGRP may play a physiological role in regulating cardiovascular function and blood pressure in hypertension.
Abstract:
In the present study the regional hemodynamic effects of CGRP were examined in conscious unrestrained spontaneously hypertensive rats (SHR). The animals were chronically instrumented with miniaturized pulsed Doppler flow probes to allow continuous measurement of renal, mesenteric and hindquarter blood flow. Bolus intravenous injection of CGRP (0.1-5 micrograms/kg) produced a dose-dependent fall in mean arterial pressure (maximal change = -48 +/- 5 mmHg) which was accompanied by a marked tachycardia (maximal change = 143 +/- 16 b/min). Depressor responses to CGRP were sustained for approximately 3-5 min. CGRP markedly reduced regional vascular resistance in all three vascular beds. No regional-selective vasodilator response was observed. These data indicate that CGRP is a potent vasodilator peptide in conscious SHR. The study suggests further that CGRP may contribute to the physiologic regulation of cardiovascular function.