An analysis of inhibitory junction potentials in the guinea-pig proximal colon
An analysis of inhibitory junction potentials in the guinea-pig proximal colon
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DOI：
10.1113/jphysiol.2004.065052
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发表时间：
2004-08-01
影响因子：
5.5
通讯作者：
Edwards, FR
中科院分区：
文献类型：
--
作者：
Hirst, GDS;Bywater, RAR;Edwards, FR
从豚鼠近端结肠的环形肌层的薄片或孤立束进行细胞内记录，并分析刺激抑制性神经纤维引起的反应。抑制性连接电位（IJPs）是由单一刺激诱发的，由两个成分组成，根据其药理学特性、时间特性和电压敏感性可将其分离。最初的成分，这是取消由apamin和吡哆醛磷酸-6-偶氮苯基-2 '，4'-二磺酸（PPADS）的幅度降低，有一个简短的时间过程：其幅度改变时，外部浓度的钾离子（[K+]（O））的变化。IJP的第二成分比第一成分起效慢，可被L-硝基精氨酸（NOLA）和可溶性鸟苷酸环化酶抑制剂恶二唑喹喔啉酮（ODQ）消除，其振幅几乎不受[K+]（o）变化的影响，当环层膜电位超极化时，其振幅增加。观察结果表明，初始组件的IJP的结果从ATP的释放，触发增加膜电导K+和第二个组件的结果从释放一氧化氮，抑制背景内向电流。
Intracellular recordings were made from either sheets or isolated bundles of the circular muscle layer of guinea-pig proximal colon and the responses evoked by stimulating inhibitory nerve fibres were analysed. Inhibitory junction potentials (IJPs), evoked by single stimuli, had two components which could be separated on their pharmacological and temporal characteristics and their voltage sensitivities. The initial component, which was abolished by apamin and reduced in amplitude by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), had a brief time course: its amplitude was changed when the external concentration of potassium ions ([K+](o)) was changed. The second component of the IJP had a slower onset than the first component, was abolished by L-nitroarginine (NOLA) and oxadiazolo quinoxalin-lone (ODQ), an inhibitor of soluble guanylate cyclase: its amplitude was little affected by changing [K+](o) and was increased when the membrane potential of the circular layer was hyperpolarized. The observations suggest that the initial component of the IJP results from the release of ATP which triggers an increase in membrane conductance to K+ and that the second component results from the release of nitric oxide which suppresses a background inward current.