Electrophysiological effects of capsaicin on guinea pig papillary muscles.
- Author:
Qian LI
1
;
Yan-Ping CHENG
;
Rui-Rong HE
Author Information
1. Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017.
- Publication Type:Journal Article
- MeSH:
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester;
pharmacology;
Action Potentials;
drug effects;
Animals;
Biological Transport, Active;
Calcium Channel Agonists;
pharmacology;
Calcium Channels, L-Type;
Capsaicin;
pharmacology;
Female;
Guinea Pigs;
Male;
Microelectrodes;
Papillary Muscles;
physiology;
Receptors, Drug;
antagonists & inhibitors;
Ruthenium Red;
pharmacology
- From:
Acta Physiologica Sinica
2003;55(5):511-515
- CountryChina
- Language:English
-
Abstract:
The cardiac electrophysiological effects of capsaicin (CAP) were examined in guinea pig papillary muscles using intracellular microelectrode technique. The results obtained are as follows: (1) the duration of action potential (APD) in normal papillary muscles was decreased by CAP (30, 60, 120 micromol/L) in a concentration-dependent manner; (2) in partially depolarized papillary muscles, 60 micromol/L CAP not only reduced APD, but also decreased the amplitude of action potential, overshoot and maximal velocity of phase 0 depolarization; (3) pretreatment with L-type Ca(2+) channel agonist Bay K8644 (0.5 micromol/L) could completely block the effects of CAP (60 micromol/L); (4) pretreatment with ruthenium red (20 micromol/L), a vanilloid receptor (VR) blocker, did not affect the actions of capsaicin on papillary muscles. All these results suggest that the effects of CAP on papillary muscles are likely due to a decrease in calcium influx which is not mediated by VR.
