Teramoto N, Hirst G D S
Department of Zoology, University of Melbourne, Victoria, Australia.
J Physiol. 2003 Jul 1;550(Pt 1):181-9. doi: 10.1113/jphysiol.2003.043273.
Intracellular recordings were made from isolated bundles of the circular muscle layer of guinea-pig gastric antrum and the responses evoked by stimulating nitrergic nerve fibres were examined. Nitrergic inhibitory junction potentials (nitrergic-IJPs), evoked by trains of stimuli, had small amplitudes and were associated with a reduction in the rate of occurrence and amplitude of spontaneously occurring depolarizing potentials, termed unitary potentials. Nitrergic-IJPs were abolished either by membrane hyperpolarization or by 4, 4'-diisothiocyano-2, 2'-stilbene disulfonic acid (DIDS); both of these abolished the discharge of unitary potentials. Membrane depolarization increased the rate of discharge of unitary potentials so that they summed to give rise to are generative potential. Nitrergic nerve stimulation abolished regenerative potentials; this inhibition did not result from a change in threshold for the initiation of regenerative potentials,rather it occurred at some stage after the gating process. Inhibitory nitrergic nerve responses were blocked by L-nitroarginine (NOLA) and oxadiazolo quinoxalin-l-one (ODQ), an inhibitor of soluble guanylate cyclase. The observations suggest that the inhibition of regenerative potentials results from an interaction between an inhibitory and an excitatory metabotropic pathway.
从豚鼠胃窦环形肌层的分离束进行细胞内记录，并检测刺激氮能神经纤维所诱发的反应。由一系列刺激诱发的氮能抑制性接头电位（氮能-IJPs）振幅较小，且与自发出现的去极化电位（称为单位电位）的发生率和振幅降低有关。氮能-IJPs可通过膜超极化或4,4'-二异硫氰基-2,2'-芪二磺酸（DIDS）消除；这两者都消除了单位电位的发放。膜去极化增加了单位电位的发放率，使其总和产生一个再生电位。氮能神经刺激消除了再生电位；这种抑制并非源于再生电位起始阈值的变化，而是发生在门控过程后的某个阶段。抑制性氮能神经反应被L-硝基精氨酸（NOLA）和可溶性鸟苷酸环化酶抑制剂恶二唑并喹喔啉-1-酮（ODQ）阻断。这些观察结果表明，再生电位的抑制是由抑制性和兴奋性代谢途径之间的相互作用引起的。
