Danilo P, Binah O, Hordof A
Department of Pharmacology, Columbia University, College of Physicians and Surgeons, New York, N.Y. 10032.
Dev Pharmacol Ther. 1993;20(3-4):231-8. doi: 10.1159/000457567.
We studied the effect of acetylcholine (ACh), 1 x 10(-8) to 5 x 10(-7) M, on electrophysiologic characteristics of the isolated (Langendorf), perfused fetal canine heart. ACh induced concentration-dependent decreases in sinoatrial (SA) rate and recovery from overdrive pacing and in atrioventricular (A-V) conduction. These effects of ACh were greater in mid-gestation than late-gestation hearts. The effects of ACh were potentiated by inhibition of acetylcholinesterase by neostigmine, 1 x 10(-7) M, in the late- but not the mid-gestation fetal heart. Decreasing the pH of the perfusion solution from 7.3 to 6.8 potentiated the response to ACh of SA rate and A-V conduction more in mid- than in late-gestation hearts. The response to ACh of the late-gestation fetal canine heart is more sensitive to cholinesterase inhibition whereas the response of the mid-gestation heart is more sensitive to the action of ACh in the presence of acidosis.
我们研究了浓度为1×10⁻⁸至5×10⁻⁷M的乙酰胆碱（ACh）对离体（Langendorf法）灌注的胎儿犬心脏电生理特性的影响。ACh可使窦房结（SA）率以及超速起搏后的恢复和房室（A-V）传导呈浓度依赖性降低。ACh对妊娠中期胎儿心脏的这些影响大于妊娠晚期胎儿心脏。在妊娠晚期而非中期胎儿心脏中，1×10⁻⁷M新斯的明抑制乙酰胆碱酯酶可增强ACh的作用。将灌注液的pH从7.3降至6.8时，妊娠中期胎儿心脏中SA率和A-V传导对ACh的反应增强程度大于妊娠晚期胎儿心脏。妊娠晚期胎儿犬心脏对ACh的反应对胆碱酯酶抑制更敏感，而妊娠中期心脏在酸中毒情况下对ACh的作用更敏感。
