Abstract:

Abstract:Objective
To explore the influence of intraventricular injection of 5,7-drhydroxytryptamine(5,7-DHT) in  5-HT1A receptor sensitivity of medial prefrontal cortex  pyramidal neurons in the  rats,and to clarity the effect of 5-HT1A receptor on the eletronic response of pyramidal neurons.Methods 36 male SD rats were randomly divided into sham operation group (n=21) and 5,7-DHT lesion group (n=15).5,7-DHT was injected  intraventricularly in the rats  in 5,7-DHT lesion group,and the same dose saline was injected in the rats in sham operation group.The rats in two groups were intravenously injected with different doses(0.5-128.0  μg•kg^-1) of 8-CH-DPAT.The firing rate  of mPFC pyramidal neurons was recorded with　extracellular　electrophysioological examination.The rats in two groups were intravenously injected with WAY100635,the sensitivites of the rats to 8-OH-DPAT and WAY100635 in 5,7-DHT lesion group were observed,and compared with  sham operation group.Results The different doses (0.5-128.0  μg•L-1) of 8-OH-DDAT had an excitatory-inhibitory effect on the firing rate of mPFC pyamidal neurons in sham operation group;the neurons were excited when the doses of 8-OH-DPAT were 0.5-38.0  μg•kg^-1,and the firing rates were increased(P<0.05);the neurons were inhibited when the dose of 8-OH-DPAT was 128.0  μg•kg^-1,and the firing rate was decreased.The different doses(0.5-218.0  μg•L^-1) of 8-OH-DPAT inhibited the elecctronic response of pyramidal neurons of the rats in 5,7-DHT lesion group in a dose-dependent manner (df=5,F=3.44，P=0.003),and the firing rates were reduced.WAY-100635 (50 μg•kg^-1) reversed completely the inhibition of 8-OH-DPAT.Conclusion The sensitivity of 5-HT1A receptor of rat mPFC pyramidal neurons  can be  decreased by intraventricular injection of 5,7-DHT.

Key words: 5, 7-drhydroxytryptamine;5-HT1A receptor;medial prefrontal cortex;pyramidal neurons;electrophysiology