%0 Journal Article
%T 5-Hydroxytryptamine enhances L-type calcium current in norepinephrine-induced hypertrophic ventricular myocytes.
%A ZHAO Ming-Gao
%A MEI Qi-Bing
%A ZHANG Yan-Feng
%A XIONG Xiao-Yun
%A LU Bao-Hua
%A XING Bin
%A ZHAO De-Hua
%J Acta Pharmacologica Sinica
%D 2016
%B 2016
%9 
%! 5-Hydroxytryptamine enhances L-type calcium current in norepinephrine-induced hypertrophic ventricular myocytes.
%K 
%X 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.
%U http://www.chinaphar.com/article/view/7643
%V 23
%N 6
%P 523-528
%@ 1745-7254