ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of 17 beta-estradiol (E2) on T-type calcium currents (ICaT) in spermatogenic cells.</p><p><b>METHODS</b>Ca2+ currents were obtained in acutely dissociated mouse spermatogenic cells by the whole-cell patch clamp technique and the effects of E2 on ICaT were observed.</p><p><b>RESULTS</b>E2 at the concentrations of 1, 10 and 100 micromol/L significantly inhibited ICaT in the mouse spermatogenic cells, with the KC50 value of 8.89 micromol/L and the inhibition rates of (13.48 +/- 1.86) %, (28.98 +/- 2.70) and (52.93 +/- 3.42)%, respectively (n = 6, P < 0.05). E2 of 100 micromol/L significantly changed the activation and inactivation of ICaT: the half activation potential (Va 1/2) and the activation steepness factor (Ka) from ( -48.94 +/- 0.22) mV and (5.19 +/- 0.19) mV to (-54.34 +/- 1.02) mV and (6.02 +/- 0.84) mV ( n = 5, P < 0.05) , and the half inactivation potential (Vi 1/2) and the inactivation steepness factor (Ki) from (-56.51 +/- 0.13) mV and (3.36 +/- 0.11) mV to (-61.78 +/- 0.50) mV and (4.25 +/- 0.37) mV, respectively (n = 5, P < 0.05).</p><p><b>CONCLUSION</b>E2 has a significant inhibitory effect on ICaT in mouse spermatogenic cells in a con-centration-dependent manner.</p>
Subject(s)
Animals , Male , Mice , Calcium Channels, T-Type , Physiology , Cells, Cultured , Dose-Response Relationship, Drug , Estradiol , Pharmacology , Membrane Potentials , Patch-Clamp Techniques , Spermatids , Cell Biology , PhysiologyABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of Flunarizine (Flu) on T-type calcium currents (ICaT) in spermatogenic cells.</p><p><b>METHODS</b>Ca2+ currents were obtained in acutely dissociated mouse spermatogenic cells using whole-cell patch clamp technique and the effects of Flu on ICaT were observed.</p><p><b>RESULTS</b>Flu of 0.1, 1, 10, 100 micromol/L inhibited ICaT in mouse spermatogenic cells significantly with the K50 value of 0.289 micromol/L (P < 0.05). With the holding potential at -90 mV and stimulating potential at -30 mV, the inhibition rates of Flu were (23.34 +/- 2.76)%, (46.04 +/- 3.52)%, (62.52 +/- 3.70)% and (73.52 +/- 3.12)%, respectively.</p><p><b>CONCLUSION</b>Flu has significant inhibitory effects on ICaT in mouse spermatogenic cells, with concentration dependence. Ca(v)3.2 is the main contributor to T-type Ca2+ currents in spermatogenic cells.</p>