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5-Hydroxytryptamine enhances L-type calcium current in norepinephrine-induced hypertrophic ventricular myocytes.
Acta Pharmacol Sin. 2002 Jun; 23(6):523-8.AP

Abstract

AIM

To study the effects of 5-hydroxytryptamine (5-HT) on L-type calcium current (ICa) in norepinephrine (NE)-induced hypertrophic ventricular myocytes.

METHODS

Left ventricular hypertrophy was induced by injecting NE intraperitoneally in rats. The single myocytes were isolated enzymatically from left ventricle. ICa was recorded with the whole-cell configuration of the patch-cl amp technique.

RESULTS

(1) The ratio of left heart weight to body weight (LHW/BW) was higher (P < 0.01) in the NE-treated rats compared with the control rats on d 15. LHW/BW was increased 31.8 % in NE-treated rats. (2) ICa was larger in hypertrophic cells than that in normal cells (4.5 p A/pF +/- 0.5 pA/pF vs 3.5 pA/pF +/- 0.3 pA/pF, respectively, at testing potential of 0 mV; P < 0.01). (3) 5-HT (1, 10 micromol/L) increased ICa and decreased the peak current potential from 0 mV to -10 mV in both myocytes. The augmentation of ICa induced by 5-HT was larger in hypertrophic ones. (4) 5-HT did not markedly influence the steady-state activation kinetics. However, 5-HT shifted steady-state inactivation curve with half inactivation voltage V 1/2 changing from -39.5 mV +/- 1.8 mV to -27.8 mV +/- 1.7 m V (P < 0.05), while not changing the voltage responsiveness of calcium channel (slope factor k was not changed markedly).

CONCLUSION

5 -HT increased ICa in ventricular myocytes by changing the kinetics of steady-st ate inactivation. A larger alteration of ICa induced by 5-HT i n hypertrophic ventricular myocytes suggests that 5-HT be more prone to induce arrhythmia in hypertrophic heart than in normal one.

Links

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Authors+Show Affiliations

Zhao MG
Department of Pharmacology, The Fourth Military Medical University, Xi-an 710032, China. mgzhao@hotmail.com
Mei QB
No affiliation info available
Zhang YF
No affiliation info available
Xiong XY
No affiliation info available
Lu BH
No affiliation info available
Xing B
No affiliation info available
Zhao DH
No affiliation info available

MeSH

AnimalsCalcium Channels, L-TypeCell SeparationElectrophysiologyHypertrophy, Left VentricularMaleMyocytes, CardiacNorepinephrinePatch-Clamp TechniquesRatsRats, Sprague-DawleySerotonin

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12060526

Citation

Zhao, Ming-Gao, et al. "5-Hydroxytryptamine Enhances L-type Calcium Current in Norepinephrine-induced Hypertrophic Ventricular Myocytes." Acta Pharmacologica Sinica, vol. 23, no. 6, 2002, pp. 523-8.
Zhao MG, Mei QB, Zhang YF, et al. 5-Hydroxytryptamine enhances L-type calcium current in norepinephrine-induced hypertrophic ventricular myocytes. Acta Pharmacol Sin. 2002;23(6):523-8.
Zhao, M. G., Mei, Q. B., Zhang, Y. F., Xiong, X. Y., Lu, B. H., Xing, B., & Zhao, D. H. (2002). 5-Hydroxytryptamine enhances L-type calcium current in norepinephrine-induced hypertrophic ventricular myocytes. Acta Pharmacologica Sinica, 23(6), 523-8.
Zhao MG, et al. 5-Hydroxytryptamine Enhances L-type Calcium Current in Norepinephrine-induced Hypertrophic Ventricular Myocytes. Acta Pharmacol Sin. 2002;23(6):523-8. PubMed PMID: 12060526.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - 5-Hydroxytryptamine enhances L-type calcium current in norepinephrine-induced hypertrophic ventricular myocytes. AU - Zhao,Ming-Gao, AU - Mei,Qi-Bing, AU - Zhang,Yan-Feng, AU - Xiong,Xiao-Yun, AU - Lu,Bao-Hua, AU - Xing,Bin, AU - Zhao,De-Hua, PY - 2002/6/13/pubmed PY - 2003/9/17/medline PY - 2002/6/13/entrez SP - 523 EP - 8 JF - Acta pharmacologica Sinica JO - Acta Pharmacol Sin VL - 23 IS - 6 N2 - AIM: To study the effects of 5-hydroxytryptamine (5-HT) on L-type calcium current (ICa) in norepinephrine (NE)-induced hypertrophic ventricular myocytes. METHODS: Left ventricular hypertrophy was induced by injecting NE intraperitoneally in rats. The single myocytes were isolated enzymatically from left ventricle. ICa was recorded with the whole-cell configuration of the patch-cl amp technique. RESULTS: (1) The ratio of left heart weight to body weight (LHW/BW) was higher (P < 0.01) in the NE-treated rats compared with the control rats on d 15. LHW/BW was increased 31.8 % in NE-treated rats. (2) ICa was larger in hypertrophic cells than that in normal cells (4.5 p A/pF +/- 0.5 pA/pF vs 3.5 pA/pF +/- 0.3 pA/pF, respectively, at testing potential of 0 mV; P < 0.01). (3) 5-HT (1, 10 micromol/L) increased ICa and decreased the peak current potential from 0 mV to -10 mV in both myocytes. The augmentation of ICa induced by 5-HT was larger in hypertrophic ones. (4) 5-HT did not markedly influence the steady-state activation kinetics. However, 5-HT shifted steady-state inactivation curve with half inactivation voltage V 1/2 changing from -39.5 mV +/- 1.8 mV to -27.8 mV +/- 1.7 m V (P < 0.05), while not changing the voltage responsiveness of calcium channel (slope factor k was not changed markedly). CONCLUSION: 5 -HT increased ICa in ventricular myocytes by changing the kinetics of steady-st ate inactivation. A larger alteration of ICa induced by 5-HT i n hypertrophic ventricular myocytes suggests that 5-HT be more prone to induce arrhythmia in hypertrophic heart than in normal one. SN - 1671-4083 UR - https://www.unboundmedicine.com/medline/citation/12060526/5_Hydroxytryptamine_enhances_L_type_calcium_current_in_norepinephrine_induced_hypertrophic_ventricular_myocytes_ L2 - http://www.chinaphar.com/1671-4083/23/523.pdf DB - PRIME DP - Unbound Medicine ER -