Aim and methods: By using blind whole-cell recording techniques, the dynamic properties of voltage-gated Ca2+ channel of CA1 pyramidal neuron in rat hippocampal slices were investigated.
Results: The voltage-gated Ca2+ channel of CA1 pyramidal neuron in rat hippocampal slices has following features: (1) The threshold potential of activation is relatively lower. The mean value is -49.3 +/- 8.6 mV with range from -65 to -30 mV (n = 23). (2) Current decay is Ca(2+) -dependent and its time constant (tau) is longer with a wide range from 100 to 700 ms (n = 12). (3) The steady-state inactivation is voltage-dependent and the half inactivation potential (V1/2) is -55.4 +/- 9.7 mV, slope factor (k) is 5.3 +/- 0.9 (n = 10). (4) The reversal potential (E(rev)) of Ca2+ channel is 55 +/- 13 mV (n = 10) when extracellular Ca2+ concentration is 2.5 mmol/L. (5) Tail current, which is voltage-independent, primarily has only one component. In addition, Ca2+ channel is insensitive to verapamil and nifedipine.
Conclusion: N-type Ca2+ channel is strongly suggested in CA1 pyramidal neuron in rat hippocampal slices.