Effect of calcitonin gene-related peptide combined with norepinephrine on L-type calcium current in rat ventricular myocytes / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of calcitonin gene-related peptide (CGRP) combined with norepinephrine (NE) on L-type calcium current (LCa-l) in rat ventricular myocytes. Methods Ventricular myocytes were isolated from SD rats (weighing 260-280 g) by retrograde perfusion of the heart via the aorta with an enzyme-containing solution as previously described. Whole-cell patch-clamp recording was made using Axopatch 200B amplifier. The cells were perfused for 1 min with Tyrode solution containing CGRP 1 × 10-7 mol/L (group CGRP) , NE 1 × 10-6 mol/L (group NE), or CGRP 1 × 10-7 mol/L + NE 1 × 10-6 mol/L (group CN) and again washed with Tyrode solution. ICa-L was recorded 1 min before and 1 min after the cells were perfused and 1 min after the cells were washed. I-V curve of ICa-L was made after the cells were perfused with solution containing CGRP or NE alone. Results CGRP significantly inhibited the peak of ICa-L, while NE significantly promoted the peak of ICa-L(P < 0.05) . The peak of ICa-L was significantly decreased 1 min after the cells were perfused in group CGRP,while increased 1 min after the cells were perfused in group NE compared with group CN ( P < 0.05). CGRP made the I-V curve of ICa-L move up-ward, while NE made the I-V curve of ICa-L move down-ward. Conclusion CGRP can weaken the promotion of ICa-L induced by NE in rat ventricular myocytes.