ABSTRACT
Aim To examine subcellular localization of serotonin 5-HT2A receptor (5-HT2AR) and glutamate NMDA receptor in dorsal hippocampal CA1 area ( dCA1 ) and further explore the effect of systemic acti-vation of 5-HT2A R on hippocampal neuronal firing rate. Methods The distribution of 5-HT2A R and NMDA re-ceptor in the dCA1 region was detected with immune e-lectron microscopy after embedding. The effect of acti-vation of 5-HT2A R on the principal neuron and inter-neuron firing rates was examined with multichannel re-cording. Results 5-HT2A R immunoreactivity was ob-served in the dCA1 neurons, including rough endoplas-mic reticula and mitochondria, and the 5-HT2A R and glutamate NMDA receptors were colocalized in the syn-aptic membrane, vesicle and neurofilament of the hipp-ocampal neuron. 5-HT2A R activation increased princi-pal neuronal firing rate and the interneuronal firing rate was not changed. Conclusion The 5-HT2A R and NM-DA receptor are colocalized in dCA1 neurons, and acti-vation of 5-HT2A R increases hippocampal principal neuronal firing rate.