Kerr K P, Stevenson J E, Mitchelson F
Victorian College of Pharmacy, Monash University, School of Pharmacology, Parkville, Victoria, Australia.
J Pharm Pharmacol. 1995 Dec;47(12A):1002-6. doi: 10.1111/j.2042-7158.1995.tb03286.x.
The relative potencies of several nicotinic cholinoceptor antagonists in producing tetanic fade and reduction of striated muscle contraction were investigated in the isolated guinea-pig oesophagus as well as the guinea-pig and rat phrenic nerve-diaphragm preparations. Contractile smooth muscle responses to vagal stimulation, which involves ganglionic activation, were also measured simultaneously with striated muscle responses in the oesophagus. The relative potency for inhibiting the response of oesophageal smooth muscle to vagal stimulation (20 Hz) was trimetaphan > mecamylamine > hexamethonium > tubocurarine > pancuronium. For oesophageal striated muscle, production of tetanic fade at 100 Hz and reduction in peak tetanic tension at 20 or 100 Hz showed a similar relative potency; pancuronium > tubocurarine > mecamylamine > trimetaphan > hexamethonium and similar results were obtained in the guinea-pig diaphragm for the antagonists investigated (pancuronium, tubocurarine and mecamylamine). In the rat phrenic nerve-diaphragm preparation, production of tetanic fade at 50 Hz and reduction in twitch or tetanic tension all showed the relative potency; tubocurarine > pancuronium > mecamylamine > trimetaphan > hexamethonium. These findings indicate differences in the nicotinic cholinoceptor subtypes involved in vagal ganglionic responses and those in tetanic fade.
在离体豚鼠食管以及豚鼠和大鼠膈神经 - 膈肌标本中，研究了几种烟碱型胆碱受体拮抗剂在产生强直衰减和降低横纹肌收缩方面的相对效力。同时还测量了食管中对迷走神经刺激（涉及神经节激活）的收缩性平滑肌反应以及横纹肌反应。抑制食管平滑肌对迷走神经刺激（20Hz）反应的相对效力为：阿方那特＞美加明＞六甲铵＞筒箭毒碱＞泮库溴铵。对于食管横纹肌，在100Hz时产生强直衰减以及在20或100Hz时降低强直峰值张力显示出相似的相对效力；泮库溴铵＞筒箭毒碱＞美加明＞阿方那特＞六甲铵，在所研究的拮抗剂（泮库溴铵、筒箭毒碱和美加明）方面，豚鼠膈肌也得到了类似结果。在大鼠膈神经 - 膈肌标本中，50Hz时产生强直衰减以及单收缩或强直张力降低均显示出相对效力：筒箭毒碱＞泮库溴铵＞美加明＞阿方那特＞六甲铵。这些发现表明，参与迷走神经节反应的烟碱型胆碱受体亚型与产生强直衰减的亚型有所不同。
