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美国卫生研究院文献>The Journal of Physiology
>Distribution and properties of excitatory and inhibitory junction potentials in circular muscle of the guinea-pig stomach.
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Distribution and properties of excitatory and inhibitory junction potentials in circular muscle of the guinea-pig stomach.
In the presence of guanethidine (10(-6)-5 X 10(-6) M), transmural nerve stimulation evoked an excitatory junction potential (e.j.p.) in the fundus region and an inhibitory junction potential (i.j.p.) in the antrum region of the circular muscle of the guinea-pig stomach. The e.j.p. was blocked by atropine (over 2 X 10(-7) M) while the i.j.p. was blocked by apamin (10(-7) M) but not by adrenergic or cholinergic receptor antagonists. Therefore the i.j.p. may be non-adrenergic and non-cholinergic in nature. In the presence of atropine, nerve stimulation evoked the non-adrenergic, non-cholinergic i.j.p. in both regions of the stomach. In the antrum region, single stimuli enhanced the subsequent slow wave by 1.1-1.3 times, in comparison with that before the stimuli, and this effect was blocked by atropine (over 2 X 10(-7) M). The reversal potential for the e.j.p. was about -18 mV, while that for the i.j.p. was -87 mV in the atropinized fundus and -89 mV in the antrum region. In the fundus region, a pair of nerve stimulations with short intervals (1-4 s) reduced (depression) and with long intervals (5-20 s) enhanced (facilitation) the second e.j.p. or the i.j.p. After inhibition of acetylcholine esterase (AChE) by physostigmine or neostigmine, nerve stimulation evoked an enhanced e.j.p., and then produced a sustained depolarization with a duration of 3-5 s in the fundus region, while the amplitude of slow waves after nerve stimulation was further enhanced in the antrum region. These effects of anticholinesterases were blocked by atropine. Exogenously applied acetylcholine (ACh) depolarized the smooth muscle membrane; the threshold concentration of ACh was about 1000 times higher in the antrum region (10(-6) M) than in the fundus region (10(-9) M). It is concluded that in the guinea-pig stomach, regional differences in junction potentials may be due to different sensitivities of ACh receptor, and that nerve stimulation evokes a cholinergic e.j.p. in a high-sensitivity region (fundus) and a non-adrenergic, non-cholinergic i.j.p. in a low-sensitivity region (antrum).
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机译:在胍乙啶(10(-6)-5 X 10(-6)M)存在的情况下,经壁神经刺激引起眼底区域的兴奋性连接电位(ejp)和胃窦区域的抑制性连接电位(ijp)。豚鼠胃的环形肌肉。 e.j.p.阿托品(超过2 X 10(-7)M)被i.j.p.被阿帕明(10(-7)M)阻断,但未被肾上腺素或胆碱能受体拮抗剂阻断。因此,i.j.p。本质上可能是非肾上腺素和非胆碱能的。在存在阿托品的情况下,神经刺激引起了非肾上腺素,非胆碱能性腹泻。在胃的两个区域。在胃窦区域,单个刺激与随后刺激相比,将随后的慢波增强了1.1-1.3倍,并且这种作用被阿托品所阻断(超过2 X 10(-7)M)。 e.j.p.的反转潜力约为-18 mV,而i.j.p.在萎缩性眼底中为-87 mV,在胃窦区域中为-89 mV。在眼底区域,一对短间隔(1-4 s)的神经刺激减少(抑郁),长间隔(5-20 s)的神经刺激增强(促进)第二个e.j.p.或i.j.p.毒扁豆碱或新斯的明抑制乙酰胆碱酯酶(AChE)后,神经刺激引起增强的ejp,然后在眼底区域持续3-5 s的持续去极化,而神经刺激后慢波的振幅进一步增加。在胃窦区域增强。抗胆碱酯酶的这些作用被阿托品阻断。外用乙酰胆碱(ACh)使平滑肌膜去极化; ACh的阈值浓度在胃底区域(10(-6)M)比在眼底区域(10(-9)M)高约1000倍。结论是在豚鼠胃中,连接电位的区域差异可能是由于ACh受体的敏感性不同所致,并且神经刺激引起了胆碱能e.j.p.。在高敏感性区域(眼底)和非肾上腺素,非胆碱能性腹膜炎。在低灵敏度区域(胃窦)。
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