Objective To study the effect of serotonergic efferent projection of the dorsal raphe nucleus(DRN)on the activity of substantia nigra pars compacta(SNc)and ventral tegmenta area(VTA)dopaminergic neurons after lesioning of the DRN by the neurotoxin 5,7-drhydroxytryptamine(5,7-DHT)in rat.Methods The changes in the firing rate and firing pattern of SNc and VTA dopaminergic neurons were observed with extracellular recording in control and the lesioned rats.Results The results showed that the mean firing rates o...
Objective The ventral part of the medial prefrontal cortex（mPFC）plays an important role in initiation and control of voluntary movement,mood and cognition.However,after the degeneration of the nigrostriatal pathway,the neuronal activity of the ventral mPFC and the role of serotonin1A（5-hydroxytryptamine,5-HT1A）receptors in the firing of the neurons are still unknown.The present study is to investigate the change of neuronal activity in the ventral mPFC and the effect of systemic administration of the selective 5-HT1Areceptor antagonist WAY-100635 on the activity of the neurons in normal and 6-hydroxydopamine（6-OHDA）-lesioned rats.Methods Single unit responses were recorded extracellularly with glass microelectrodes from ventral mPFC neurons in normal rats and 6-OHDA unilaterally lesiond rats in vivo.Results 6-OHDA lesion of the substantia nigra pars compacta（SNc）significantly increased the firing rate with no change in the firing pattern of neurons of the ventral mPFC in rats.Systemic administration of WAY-100635（0.1 mg/kg,i.v.）did not change the mean firing rate and firing pattern of ventral mPFC neurons in normal rats.In contrast,WAY-100635 signifi- cantly decreased the mean firing rate of the neurons in rats with 6-OHDA lesion of the SNc.Conclusion These data suggest that the degeneration of the nigrostriatal pathway results in an increase of neuronal activity of ventral mPFC and dysfunction of 5-HT1Areceptor.
