- 作者: cheng-I Lin Ming-Yu Yiu Hwong-Ru Hwang Chin-Lun Lin Kuan-Yii Chen
- 作者服務機構: Institute of Pharmacology and Department of Blomedical Englneering, National Defense Medical center, Taipei, Taiwan, ROC
- 中文摘要: --
- 英文摘要: We studied the role of acetylcholine (ACh) and calciumoverload in the induction of atrial flutter or atrial fibrilla-tion (AF)in right atria from 34 normal male Syrian ham-sters(F1B)and 33 cardiomyopathic Syrian hamsters(BIO 14.6) associated with focal myocardial necrosis.Action potential (AP) was recorded with conventionalmicroelectrode techniques and twitch force by a trans-ducer. ACh (0.1, 1 and 10 μM)induced high-frequencyAF(around 33 Hz) along with tension oscillations andcontracture in 7 of 12 norma∣hamster atria. These effectsof ACh were abolished by tetrodotoxin or quinidine aswell as by atropine. In contrast, ACh induced AF only in 1of 12 myopathic atria. In both normal and myopathicatria, ACh induced similar changes in AP duration, spon-taneous rate and force. The effects of calcium overloadwere tested by means of a high [Ca ] (8.1 mM) low[K ] (1mM) solution in another series of experiments.This solution also induced incidence of AF higher in nor-mal (10/12) than in myopathic atria (4/12). The calciumload was also increased by high-frequency pacing (32 Hzfor 3 or 30 s): AF occurred in normal atria (5/8), but not inmyopathic atria (0/8). Measurement of the refractoryperiod revealed a longer refractory period in myopathicthan in control atria. We concluded that the lower inci-dence of AF in myopathic atria was probably due to theirlonger refractory period and the associated focal myo-cardial necrosis which then hindered the establishmentof such a reentrant rhythm.
- 中文關鍵字: --
- 英文關鍵字: Acetylcholine. Hamster atria. arrhythmia, supraventricular. calcium overload. membrane Potential. Necrosis