S Yang1, J E Liu, A Z Zhang, M H Jiang. 1. Department of Pharmacology, School of Pharmacy, Shanghai Medical University, Shanghai 200032, China. mhjiang@shmu.edu.cn
Abstract
AIM: To investigate the effect of melittin (Mel) on isolated guinea pig atria. METHODS: The effect of Mel on the contraction and heart rate of isolated guinea pig atria at different concentrations was determined. RESULTS: Mel at a lower concentration (0.1-0.8 mumol.L-1) enhanced the contraction of left atria in a concentration-dependent manner; but at a higher concentration (1.6-12.8 mumol.L-1) it exerted an inhibitory effect. At 0.1-30 mumol.L-1 it was found to increase heart rate of right atria. In addition, verapamil (Ver) 0.3 mumol.L-1 was found to depress the effect of Mel. CONCLUSION: Mel possesses a biphasic effect on left atria and a positive chronotropic effect on right atria. Its mechanism might be related with Ca2+ channel.
AIM: To investigate the effect of melittin (Mel) on isolated guinea pig atria. METHODS: The effect of Mel on the contraction and heart rate of isolated guinea pig atria at different concentrations was determined. RESULTS: Mel at a lower concentration (0.1-0.8 mumol.L-1) enhanced the contraction of left atria in a concentration-dependent manner; but at a higher concentration (1.6-12.8 mumol.L-1) it exerted an inhibitory effect. At 0.1-30 mumol.L-1 it was found to increase heart rate of right atria. In addition, verapamil (Ver) 0.3 mumol.L-1 was found to depress the effect of Mel. CONCLUSION: Mel possesses a biphasic effect on left atria and a positive chronotropic effect on right atria. Its mechanism might be related with Ca2+ channel.