Role of calcium in mediating the biphasic contraction of the rabbit urinary bladder.
Role of calcium in mediating the biphasic contraction of the rabbit urinary bladder.
复制标题
钙在介导兔膀胱双相收缩中的作用。
DOI：
10.1016/0306-3623(93)90238-s
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Levin,RM
中科院分区：
文献类型：
--
作者：
Zhao,Y;Wein,AJ;Levin,RM
1.膀胱对场刺激的反应本质上是双相的，包括初始阶段性收缩，随后是持续刺激持续时间的延长的强直阶段。2.阶段性反应由神经体液递质的释放介导，主要是乙酰胆碱（通过毒蕈碱受体刺激）和ATP（通过嘌呤能受体刺激）。紧张成分完全通过毒蕈碱受体刺激介导。3.本研究探讨了依赖于细胞外钙的阶段性和紧张性收缩反应，场刺激，氨甲酰胆碱，和ATP。研究结果如下：4.场刺激（2和32 Hz）和氨甲酰胆碱引起双相收缩反应，而ATP只引起相反应。5.无论是钙通道阻滞剂或钙fee EGTA介质对自发收缩或肌条的基础张力没有显着影响。6.钙通道拮抗剂地尔硫卓和维拉帕米以剂量依赖性方式抑制场刺激（2和32 Hz）引起的相位和紧张性反应。7.对于2和32 Hz刺激，抑制对场刺激的反应的强直相的ED 50 s显著低于抑制相反应的ED 50 s。8.在含有EGTA的无钙培养基中孵育，对场刺激的反应的强直相被抑制到比阶段性反应显著更大的程度。9.对氨甲酰胆碱刺激的反应的阶段性和紧张性成分均被抑制，并且遵循与场刺激的紧张性成分相似的时间过程。（250字处删节）
1. The response of the urinary bladder to field stimulation is biphasic in nature consisting of an initial phasic contraction followed by a prolonged tonic phase which lasts for the duration of the stimulation. 2. The phasic response is mediated by the release of neurohumoral transmitters, primarily acetylcholine (via muscarinic receptor stimulation) and ATP (via purinergic receptor stimulation). The tonic component is mediated entirely via muscarinic receptor stimulation. 3. The present study investigates the dependence on extracellular calcium of the phasic and tonic contractile responses to field stimulation, bethanechol, and ATP. The results can be summarized as follows: 4. Field stimulation (2 and 32 Hz) and bethanechol evoke a biphasic contractile response whereas ATP evokes only a phasic response. 5. There were no significant effects of either calcium channel blockers or calcium fee EGTA medium on either spontaneous contraction or basal tension of muscle strips. 6. The calcium channel antagonists diltiazem and verapamil inhibited both the phasic and tonic responses induced by field stimulation (both 2 and 32 Hz) in a dose dependent manner. 7. For both 2 and 32 Hz stimulation, the ED50 s for the inhibition of the tonic phases of the responses to field stimulation were significantly lower than the ED50s for the inhibition of the phasic responses. 8. The tonic phase of the responses to field stimulation were inhibited to a significantly greater degree than the phasic responses by incubation in calcium-free medium containing EGTA. 9. Both the phasic and tonic components of the response to bethanechol stimulation were inhibited equally, and followed a similar time course as the tonic component of field stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)