Chiba S
Eur J Pharmacol. 1976 Jul;38(1):89-94. doi: 10.1016/0014-2999(76)90204-1.
The isolated right atrium of the dog heart was perfused with arterial blood introduced from a carotid artery of a support dog. The selective administration of pentobarbital into the cannulated sinus node artery induced a negative inotropic effect without any significant change in chronotropism at relatively small doses. At higher doses, pentobarbital caused both negative chronotropic and inotropic effects. Even at that time, the negative chronotropic response to pentobarbital was much less than the negative inotropic response. Accordingly, pentobarbital could show a dissociation of electrical and mechanical activity in this preparation. On the other hand, either verapamil or manganese caused a negative chronotropic effect at the threshold dose for inducing a negative inotropic effect. It is suggested that the mode of cardiac action of pentobarbital may differ from calcium antagonists such as manganese or verapamil, although pentobarbital-induced effects may be associated with an impaired removal of calcium ion.
用从供血犬颈动脉引入的动脉血灌注犬心脏的离体右心房。向插管的窦房结动脉选择性给予戊巴比妥，在相对小剂量时可诱导负性肌力作用，而变时性无任何显著变化。在较高剂量时，戊巴比妥可引起负性变时性和负性肌力作用。即便在那时，戊巴比妥引起的负性变时性反应远小于负性肌力反应。因此，在该制剂中戊巴比妥可表现出电活动和机械活动的分离。另一方面，维拉帕米或锰在诱导负性肌力作用的阈剂量时引起负性变时性作用。提示戊巴比妥的心脏作用模式可能不同于锰或维拉帕米等钙拮抗剂，尽管戊巴比妥诱导的效应可能与钙离子清除受损有关。
