Zhang Y, Gu S Z, Hao Y C, Song L L, Guo S M, Lu S G
Department of Physiology, Hebei Medical University, Shijiazhuang, China.
Zhongguo Yao Li Xue Bao. 1996 Sep;17(5):439-41.
To study the effects of sodium pentobarbital (SP) on the action potential (AP) and contraction of guinea pig papillary muscle.
Using conventional glass microelectrode and mechanical recording of myocardium contraction.
SP (> or = 10 mumol.L-1) prolonged the AP duration (APD) and effective refractory period (ERP), while amplitude (APA) and Vmax of phase 0 showed no changes. The effects of SP were abolished by pretreatment with cromakalim, an agonist of ATP-sensitive K+ channel. The maximal isometric tension (Pmax) and velocity of tension development (dT/dt) were decreased to 51% and 48% of control, respectively. The first postrest beat (B1) and second postrest beat (B2) were also depressed.
SP affected the action potential by reducing activities of the K+ channels and reduced the contraction of guinea pig myocardium.
研究戊巴比妥钠（SP）对豚鼠乳头肌动作电位（AP）及收缩的影响。
采用常规玻璃微电极并进行心肌收缩的机械记录。
SP（≥10μmol·L-1）可延长动作电位时程（APD）和有效不应期（ERP），而0期振幅（APA）和最大除极速度（Vmax）无变化。ATP敏感性钾通道激动剂克罗卡林预处理可消除SP的作用。最大等长张力（Pmax）和张力发展速度（dT/dt）分别降至对照的51%和48%。静息后第一个搏动（B1）和第二个搏动（B2）也受到抑制。
SP通过降低钾通道活性影响动作电位，并降低豚鼠心肌收缩力。
