[Effect of batroxobin on K+ channel activated by Ca2+ in primary culture rat cortex neurons of rat].

Objective: To investigate the effect of batroxobin on K+ channel activated by Ca2+ in primary cultured cortex neurons of fetal SD rat.
Methods: The patch clamp technique of single channel recordings including cell-attach and inside-out mode was used.
Results: Extracellular batroxobin activated the Kca. In Ca2+ bath solution of cell-attach mode, Vp +30 mV, when the concentrations of batroxobin were 0.15, 0.25, 0.50, 0.75 and 1.0 mmol/L, the open probabilities of the channel were 0.013 +/- 0.002, 0.082 +/- 0.011, 0.131+/- 0.012, 0.211+/- 0.010 and 0.062 +/- 0.009 (P < 0.01), respectively. It appeared concentration-dependent within 0.75 mmol/ L. batroxobin. In Ca2+ free-bath solution of cell-attach mode, Vp+50 mV, when the concentrations of batroxobin were 0.15, 0.40, 0.60 and 1.0 mmol/L, the open probabilities of the channel were 0.013 +/- 0.001, 0.112 +/- 0.007, 0.193 +/- 0.010 and 0.301 +/- 0.009 (P < 0.05), respectively. In the 6 cases of inside-out mode patch clamp, Vp +40 mV, when the concentrations of batroxobin were 0, 0.25 and 0.50 mmol/L, the open probabilities of the channel were 0. 012 +/- 0.007, 0.011 +/- 0.009 and 0.013 +/- 0.008 (P > 0.05), respectively. There was no significant difference in open probabilities, average open/close times and amplitudes at different intracellular batroxobin concentrations.
Conclusion: Batroxobin can affect the activation of the Kca channel through regulating the concentration of cytoplasmic free Ca2+. It may have a protective effect on neurons.