Electrophysiological properties of pyramidal neurons of the early postnatal stage rat visual cortex / 西安交通大学学报(医学版)

ABSTRACT

Objective To investigate the electrophysiological properties of layer Ⅱ/Ⅲ pyramidal neurons of the early postnatal stage rat visual cortex.Methods By using the whole cell patch-clamp recording technique combined with direct visualization of cells,we studied the passive and active electrophysiological properties as well as firing properties of layer Ⅱ/Ⅲ pyramidal neurons in acute rat visual cortical slices.Results Resting membrane potential,input resistance,membrane capacitance and membrane time constant of pyramidal neurons at postnatal days 11-13(P 11-13) were(-56.6?1.8)mV,(185.4?2.7)M?,(77.9?2.2)pF and(16.9?2.4)ms,respectively.Action potential amplitude and duration were(97.7?2.7)mV and(2.3?0.1)ms,respectively.Threshold potential was(-31.8?1.2)mV and afterdepolarizing potential was(-65.3?1.1)mV.When presented with long depolarizing current pulse of constant amplitude,most of the neurons exhibited pronounced adaptation of spike frequency.The steady-state firing frequency was(30.4?9.4)% of the first interval firing frequency.Conclusion The electrophysiological properties of layer Ⅱ/Ⅲ pyramidal neurons of the early postnatal stage rat visual cortex are not fully mature.Most of the neurons display regular firing patterns,but the degree of firing frequency adaptation is relatively small.