Time course of the increase in the myocardial slow inward current after a photochemically generated concentration jump of intracellular cAMP.
Time course of the increase in the myocardial slow inward current after a photochemically generated concentration jump of intracellular cAMP.
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光化学产生的细胞内 cAMP 浓度跳跃后心肌缓慢内向电流增加的时间过程。
DOI：
10.1073/pnas.80.8.2395
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发表时间：
1983
影响因子：
11.1
通讯作者：
Lester,HA
中科院分区：
文献类型：
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作者：
Nargeot,J;Nerbonne,JM;Engels,J;Lester,HA
将牛蛙心脏的电压钳位心房小梁暴露于cAMP和cGMP的膜渗透性光解邻硝基苄基酯。紫外线闪光产生细胞内cAMP或cGMP浓度跳跃。使用cAMP衍生物，闪光导致缓慢内向电流（Isi）增加，产生加宽的动作电位。在闪光后10-30秒，Isi达到最大值，并在接下来的60-300秒内下降。在150 msec内可观察到第一次增加;该值是仪器施加的上限。闪光的反应持续时间较长，在较高的药物浓度和磷酸二酯酶抑制剂罂粟碱的存在下，闪光的影响发展和下降速度在较高的温度。虽然Isi的幅度增加，但其波形和电压灵敏度不受影响。细胞内cAMP浓度跃变不影响毒蕈碱K+电导。未观察到cGMP浓度跳跃效应。数据证实（i）cAMP调节Isi和（ii）在先前研究中观察到的应用β-激动剂和正性肌力作用开始之间的5- 10秒延迟，已正确归因于cAMP和蛋白激酶之间相互作用之前的事件。
Voltage-clamped atrial trabeculae from bullfrog hearts were exposed to membrane-permeant photolyzable o-nitrobenzyl esters of cAMP and cGMP. UV flashes produced intracellular concentration jumps of cAMP or cGMP. With the cAMP derivative, flashes resulted in an increased slow inward current (Isi), producing a broadened action potential. The Isi reached a maximum 10-30 sec after the flash and decreased over the next 60-300 sec. The first increases were observable within 150 msec; this value is an upper limit imposed by the instrumentation. Responses to flashes lasted longer at higher drug concentrations and in the presence of the phosphodiesterase inhibitor papaverine; effects of flashes developed and decreased faster at higher temperature. Although the amplitude of the Isi was increased, its waveform and voltage sensitivity were not affected. Intracellular concentration jumps of cAMP failed to affect the muscarinic K+ conductance. There were no observable effects of cGMP concentration jumps. The data confirm (i) that cAMP regulates the Isi and (ii) that the 5- to 10-sec delay between application of beta-agonists and the onset of positive inotropic effects, observed in previous studies, has been correctly ascribed to events prior to the interaction between cAMP and protein kinase.
瓦瑟曼
影响因子：
--
作者：
Julien Rouzot;Julien Ferry;Marie
通讯作者：
Marie