每年出版 4 期
ISSN 打印: 2155-014X
ISSN 在线: 2155-0158
Nonuniform Distribution and Contribution of P- and P/Q-Types Calcium Channels to Short-Term Inhibitory Synaptic Plasticity in Cultured Hippocampal Neurons
摘要
In the present study, we investigated the sensitivity of GABAergic short-term plasticity to selective P- and P/Q-type calcium channels blocker omega-agatoxin-IVA. To block P-type channels we used 30 nM of this toxin and to block P/Q-types - 200 nM. Evoked inhibitory postsynaptic currents (elPSC) were studied using patch-clamp technique in whole-cell configuration in postsynaptic neuron and local extracellular stimulation of single presynaptic axon by rectangular pulse. The present data show that contribution of P- and P/Q-types channels to GABAergic synaptic transmission in cultured hippocampal neurons are 30% and 45%, respectively. It was shown that mediate contribution of P- and P/Q-types channels to amplitudes of elPSC is different to every discovered neuron. it means that distribution of these channels is nonunifirm. To study short-term plasticity of inhibitory synaptic transmission the axon of presynaptic neuron was paired-pulse stimulated. The interpulse interval in pair was 150 ms. neurons demonstrated both depression and facilitation. The application of 30 nM and 200 nM of blocker decreased depression and increased facilitation to 8% and 11%, respectively. In addition we found that mediate contribution of P- and P/Q-types channels to realization synaptic transmission after second stimuli is less to 4% than after first. Therefore, blocking both P-and P/Q-types calcium channels can change efficiency of synaptic transmission. In this instance it facilitates realization of the transmission by decrease depression or increase facilitation. These results confirm that P- and P/Q-types calcium channels are involved in regulation of short-term inhibitory synaptic plasticity in cultured hippocampal neurons.