Effects of endogenous and exogenous nitric oxide on electrical responses of circular smooth muscle isolated from the guinea-pig stomach antrum
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- Nakamura Eri
- Department of Physiology, Nagoya City University Medical School
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- Lee Kyu Pil
- Department of Physiology and Biophysics, Seoul National University College of Medicine
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- So Insuk
- Department of Physiology and Biophysics, Seoul National University College of Medicine
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- Kim Ki Whan
- Department of Physiology and Biophysics, Seoul National University College of Medicine
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- Suzuki Hikaru
- Department of Physiology, Nagoya City University Medical School
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抄録
The effects of endogenous and exogenous nitric oxide (NO) on electrical activity were investigated in circular smooth muscle preparations isolated from the guinea-pig stomach antrum. The actions of endogenous NO were evaluated from the effects of inhibition of NO synthesis by Nω-nitro-L-arginine (nitroarginine), while those of exogenous NO were assessed from the effects of SIN-1, an NO donor. Antral circular smooth muscle generated slow potentials periodically at a frequency of about 1 cycle per min (cpm), and unitary potentials were also generated in a random fashion in the interval between slow potentials. Application of nitroarginine (10-5 M) increased the frequency of slow potentials, with no significant alteration of the resting membrane potential and amplitude of slow potentials. Frequency analysis of unitary potentials revealed that nitroarginine also increased the spectral density at 0.01-1 Hz frequency. The refractory period for the generation of slow potentials evoked by depolarizing pulses was about 10 s, but was decreased to 6 s by nitroarginine. In the presence of nitroarginine, SIN-1 (10-9-10-7 M) reduced the amplitude and frequency of slow potentials: low concentrations (<10-8 M) reduced only the frequency of slow potentials, while higher concentrations (10-8-10-7 M) reduced both the amplitude and frequency of slow potentials, in a concentration-dependent manner, before abolishing the slow potentials. The power spectrum of the unitary potentials indicated that SIN-1 (>10-8 M) reduced the spectral density at 0.01-1 Hz frequency. The refractory period for the generation of slow potentials was increased again to about 10 s by SIN-1. Thus, the excitatory effects of nitroarginine could be antagonized by SIN-1, suggesting that the inhibitory effects of endogenous NO are comparable to those of exogenous NO produced by SIN-1. The results also suggested that the effects of NO on smooth muscle are insignificant and NO selectively inhibits the activity of intramuscular interstitial cells of Cajal (ICC-IM).<br>
収録刊行物
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- Journal of Smooth Muscle Research
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Journal of Smooth Muscle Research 40 (4/5), 183-198, 2004
日本平滑筋学会
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詳細情報 詳細情報について
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- CRID
- 1390282680032747904
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- NII論文ID
- 110002952051
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- NII書誌ID
- AN10364204
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- ISSN
- 18848796
- 09168737
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- PubMed
- 15655306
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- 本文言語コード
- en
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- データソース種別
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- JaLC
- Crossref
- PubMed
- CiNii Articles
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- 抄録ライセンスフラグ
- 使用不可