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KMID : 0377220000250020022
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Medical Journal of Chosun Univercity
2000 Volume.25 No. 2 p.22 ~ p.28
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Effects of Imipramine on A-type K^+ Current in Murine Proximal Colon
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Yoon Hong
Choi Hyun-Dong
Lee Jeong-Hoe
Cho Cheol-Hee
Kim Gi-Sig
Shin Moo-Kyoung
Yeum Cheol-Ho
Yoon Pyung-Jin
Jun Jae-Yeoul
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Abstract
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To investigate of effects of imipramine, an antidepressant agent, on delayed rectifier K+ currents in murine proximal colonic smooth muscle cells, A-type delayed rectifier K+ currents were recorded from isolated cells using the standard whole-cell configuration. Depolarizing test pulses between -80 mV and +30 mV with 10 mV increment from the holding potential of -80 mV activated voltage-dependent outward K+ currents that peaked within 50 ms followed slow decreasing sustained currents. Early peak currents were inhibited by the application of 4-AP, whereas sustained currents were inhibited by the application of TEA. Bath application of imipramine inhibited the 4-AP sensitive A-type K+ currents, dose-dependently. But, half-inactivation potential and half-recovery time were not changed by imipramine. The imipramine-induced inhibition was not changed when 1 mM guanosine 5-O-(2-thiodiphosphate) (GDPβS) was in the pipette. Also, in the presence of chelerythrine, a protein kinase C inhibitor, imipramine-induced inhibition was not changed. These results suggest that imipramine inhibits A-type delayed rectifier K+ currents by G-protein and protein kinase C- independent manner.
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KEYWORD
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imipramine
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