Regulation of L-type calcium channel current by somatostatin in guinea-pig gastric myocytes

Young Chul Kim, Jae Hoon Sim, Sang Jin Lee, Tong Mook Kang, Sungjoon Kim, Seung Ryul Kim, Sei Jin Youn, Sang Jeon Lee, Wen Xie Xu, Insuk So, Ki Whan Kim

Research output: Contribution to journalArticleResearchpeer-review

Abstract

To study the direct effect of somatostatin (SS) on calcium channel current (I Ba ) in guinea-pig gastric myocytes, I Ba was recorded by using whole-cell patch clamp technique in single smooth muscle cells. Nicardipine (I μM), a L-type Ca 2+ channel blocker, inhibited I Ba by 98±1.9% (n=5), however I Ba was decreased in a reversible manner by application of SS. The peak I Ba at 0 mV were decreased to 95 ± 1.1, 92±1.9, 82±4.0, 66±5.8, 10±2.9% at 10 -10 , 10 -9 , 10 -8 , 10 -7 , 10 -5 M of SS, respectively (n=3-6; mean± SEM). The steady-state activation and inactivation curves of I Ba as a function of membrane potentials were well fitted by a Boltzmann equation. Voltage of half-activation (V 0.5 ) was -12±0.5 mV in control and -11±1.9 mV in SS treated groups (respectively, n=5). The same values of half-inactivation were - 35 ± 1.4 mV and -35 ± 1.9 mV (respectively, n=5). There was no significant difference in activation and inactivation kinetics of I Ba by SS. Inhibitory effect of SS on I Ba was significantly reduced by either dialysis of intracellular solution with GDP β S, a non-hydrolysable G protein inhibitor, or pretreatment with pertussis toxin (PTX). SS also decreased contraction of guinea-pig gastric antral smooth muscle. In conclusion, SS decreases voltage-dependent L-type calcium channel current (VDCC L ) via PTX-sensitive signaling pathways in guinea-pig antral circular myocytes.

Original languageEnglish
Pages (from-to)103-108
Number of pages6
JournalKorean Journal of Physiology and Pharmacology
Volume9
Issue number2
StatePublished - 1 Apr 2005

Fingerprint

L-Type Calcium Channels
Somatostatin
Muscle Cells
Stomach
Guinea Pigs
Pertussis Toxin
Calcium Channels
Nicardipine
Dialysis Solutions
Patch-Clamp Techniques
GTP-Binding Proteins
Membrane Potentials
Smooth Muscle Myocytes
Smooth Muscle

Keywords

  • Calcium current
  • G-protein
  • Gastric myocytes
  • Somatostatin

Cite this

Kim, Y. C., Sim, J. H., Lee, S. J., Kang, T. M., Kim, S., Kim, S. R., ... Kim, K. W. (2005). Regulation of L-type calcium channel current by somatostatin in guinea-pig gastric myocytes. Korean Journal of Physiology and Pharmacology, 9(2), 103-108.
Kim, Young Chul ; Sim, Jae Hoon ; Lee, Sang Jin ; Kang, Tong Mook ; Kim, Sungjoon ; Kim, Seung Ryul ; Youn, Sei Jin ; Lee, Sang Jeon ; Xu, Wen Xie ; So, Insuk ; Kim, Ki Whan. / Regulation of L-type calcium channel current by somatostatin in guinea-pig gastric myocytes. In: Korean Journal of Physiology and Pharmacology. 2005 ; Vol. 9, No. 2. pp. 103-108.
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title = "Regulation of L-type calcium channel current by somatostatin in guinea-pig gastric myocytes",
abstract = "To study the direct effect of somatostatin (SS) on calcium channel current (I Ba ) in guinea-pig gastric myocytes, I Ba was recorded by using whole-cell patch clamp technique in single smooth muscle cells. Nicardipine (I μM), a L-type Ca 2+ channel blocker, inhibited I Ba by 98±1.9{\%} (n=5), however I Ba was decreased in a reversible manner by application of SS. The peak I Ba at 0 mV were decreased to 95 ± 1.1, 92±1.9, 82±4.0, 66±5.8, 10±2.9{\%} at 10 -10 , 10 -9 , 10 -8 , 10 -7 , 10 -5 M of SS, respectively (n=3-6; mean± SEM). The steady-state activation and inactivation curves of I Ba as a function of membrane potentials were well fitted by a Boltzmann equation. Voltage of half-activation (V 0.5 ) was -12±0.5 mV in control and -11±1.9 mV in SS treated groups (respectively, n=5). The same values of half-inactivation were - 35 ± 1.4 mV and -35 ± 1.9 mV (respectively, n=5). There was no significant difference in activation and inactivation kinetics of I Ba by SS. Inhibitory effect of SS on I Ba was significantly reduced by either dialysis of intracellular solution with GDP β S, a non-hydrolysable G protein inhibitor, or pretreatment with pertussis toxin (PTX). SS also decreased contraction of guinea-pig gastric antral smooth muscle. In conclusion, SS decreases voltage-dependent L-type calcium channel current (VDCC L ) via PTX-sensitive signaling pathways in guinea-pig antral circular myocytes.",
keywords = "Calcium current, G-protein, Gastric myocytes, Somatostatin",
author = "Kim, {Young Chul} and Sim, {Jae Hoon} and Lee, {Sang Jin} and Kang, {Tong Mook} and Sungjoon Kim and Kim, {Seung Ryul} and Youn, {Sei Jin} and Lee, {Sang Jeon} and Xu, {Wen Xie} and Insuk So and Kim, {Ki Whan}",
year = "2005",
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Kim, YC, Sim, JH, Lee, SJ, Kang, TM, Kim, S, Kim, SR, Youn, SJ, Lee, SJ, Xu, WX, So, I & Kim, KW 2005, 'Regulation of L-type calcium channel current by somatostatin in guinea-pig gastric myocytes', Korean Journal of Physiology and Pharmacology, vol. 9, no. 2, pp. 103-108.

Regulation of L-type calcium channel current by somatostatin in guinea-pig gastric myocytes. / Kim, Young Chul; Sim, Jae Hoon; Lee, Sang Jin; Kang, Tong Mook; Kim, Sungjoon; Kim, Seung Ryul; Youn, Sei Jin; Lee, Sang Jeon; Xu, Wen Xie; So, Insuk; Kim, Ki Whan.

In: Korean Journal of Physiology and Pharmacology, Vol. 9, No. 2, 01.04.2005, p. 103-108.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Regulation of L-type calcium channel current by somatostatin in guinea-pig gastric myocytes

AU - Kim, Young Chul

AU - Sim, Jae Hoon

AU - Lee, Sang Jin

AU - Kang, Tong Mook

AU - Kim, Sungjoon

AU - Kim, Seung Ryul

AU - Youn, Sei Jin

AU - Lee, Sang Jeon

AU - Xu, Wen Xie

AU - So, Insuk

AU - Kim, Ki Whan

PY - 2005/4/1

Y1 - 2005/4/1

N2 - To study the direct effect of somatostatin (SS) on calcium channel current (I Ba ) in guinea-pig gastric myocytes, I Ba was recorded by using whole-cell patch clamp technique in single smooth muscle cells. Nicardipine (I μM), a L-type Ca 2+ channel blocker, inhibited I Ba by 98±1.9% (n=5), however I Ba was decreased in a reversible manner by application of SS. The peak I Ba at 0 mV were decreased to 95 ± 1.1, 92±1.9, 82±4.0, 66±5.8, 10±2.9% at 10 -10 , 10 -9 , 10 -8 , 10 -7 , 10 -5 M of SS, respectively (n=3-6; mean± SEM). The steady-state activation and inactivation curves of I Ba as a function of membrane potentials were well fitted by a Boltzmann equation. Voltage of half-activation (V 0.5 ) was -12±0.5 mV in control and -11±1.9 mV in SS treated groups (respectively, n=5). The same values of half-inactivation were - 35 ± 1.4 mV and -35 ± 1.9 mV (respectively, n=5). There was no significant difference in activation and inactivation kinetics of I Ba by SS. Inhibitory effect of SS on I Ba was significantly reduced by either dialysis of intracellular solution with GDP β S, a non-hydrolysable G protein inhibitor, or pretreatment with pertussis toxin (PTX). SS also decreased contraction of guinea-pig gastric antral smooth muscle. In conclusion, SS decreases voltage-dependent L-type calcium channel current (VDCC L ) via PTX-sensitive signaling pathways in guinea-pig antral circular myocytes.

AB - To study the direct effect of somatostatin (SS) on calcium channel current (I Ba ) in guinea-pig gastric myocytes, I Ba was recorded by using whole-cell patch clamp technique in single smooth muscle cells. Nicardipine (I μM), a L-type Ca 2+ channel blocker, inhibited I Ba by 98±1.9% (n=5), however I Ba was decreased in a reversible manner by application of SS. The peak I Ba at 0 mV were decreased to 95 ± 1.1, 92±1.9, 82±4.0, 66±5.8, 10±2.9% at 10 -10 , 10 -9 , 10 -8 , 10 -7 , 10 -5 M of SS, respectively (n=3-6; mean± SEM). The steady-state activation and inactivation curves of I Ba as a function of membrane potentials were well fitted by a Boltzmann equation. Voltage of half-activation (V 0.5 ) was -12±0.5 mV in control and -11±1.9 mV in SS treated groups (respectively, n=5). The same values of half-inactivation were - 35 ± 1.4 mV and -35 ± 1.9 mV (respectively, n=5). There was no significant difference in activation and inactivation kinetics of I Ba by SS. Inhibitory effect of SS on I Ba was significantly reduced by either dialysis of intracellular solution with GDP β S, a non-hydrolysable G protein inhibitor, or pretreatment with pertussis toxin (PTX). SS also decreased contraction of guinea-pig gastric antral smooth muscle. In conclusion, SS decreases voltage-dependent L-type calcium channel current (VDCC L ) via PTX-sensitive signaling pathways in guinea-pig antral circular myocytes.

KW - Calcium current

KW - G-protein

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KW - Somatostatin

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