烟酰胺对心脏收缩力和缓慢内向电流的影响。
Effects of nicotinamide on cardiac contraction force and slow inward current.
作者信息
Mao X M, Li D M, Zhou C M, Wang X W, Zhang K J
机构信息
Department of Pharmacology, Xinjiang Medical College, Urümqi, China.
出版信息
Zhongguo Yao Li Xue Bao. 1993 Nov;14(6):514-6.
The effects of nicotinamide (Nic) on cardiac contraction force and on slow inward current (Isi) in guinea pigs were studied with atrial strips and voltage clamp techniques. Verapamil (Ver), MnCl2, nifedipine (Nif), and propranolol (Pro) depressed markedly the positive inotropic effect induced by Nic in a noncompetitive manner. The pD2 values of Ver, MnCl2, Nif, and Pro were 6.19, 3.41, 5.00, and 6.43, respectively. The action of Nic was reduced by a low Ca2+ Tyrode solution and disappeared in a Ca(2+)-free solution. Nic 33 mmol.L-1 elevated the Isi from 6.5 +/- 1.3 microA to 10.3 +/- 2.2 microA. The results suggest that Nic promotes the Ca2+ influx and its site of action is different from that of both Pro and the calcium antagonists.
采用心房肌条和电压钳技术研究了烟酰胺（Nic）对豚鼠心脏收缩力和慢内向电流（Isi）的影响。维拉帕米（Ver）、氯化锰（MnCl2）、硝苯地平（Nif）和普萘洛尔（Pro）以非竞争性方式显著抑制了Nic诱导的正性肌力作用。Ver、MnCl2、Nif和Pro的pD2值分别为6.19、3.41、5.00和6.43。低钙台氏液可降低Nic的作用，无钙溶液中其作用消失。33 mmol.L-1的Nic使Isi从6.5±1.3 μA升高至10.3±2.2 μA。结果提示，Nic促进Ca2+内流，其作用部位与Pro和钙拮抗剂均不同。
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