A Study On The Role And Mechanism Of The Perifornical Area In The Locomotor Activity And Feeding Of Mice

Objective:Orexinergic neurons in the pelvic encapsulated fluid(Pe F),which can emit fibers widely into many brain regions,and participate in the regulation of exercise,drinking,and feeding.The purpose of this study was to explore the nerve fiber connections between the perifornical nucleus and the hypothalamic hippocampus,and to elucidate the role and potential mechanism of the perifornical nucleus in the circadian rhythm of spontaneous activity,feeding and drinking water in mice.Methods:Male Kunming mice,20-25 g.Mouse pelvic encapsulated fluid brain region was destroyed by a one-sided implant electrode method.The fluorescent fiber retrograde tracing method was used to observe the neurofibrous connection between the Hi-CA1 and Pe F in mice.The number of orexin-A immunoreactive cells in Pe F was observed by immunohistochemistry after unilateral Pe F-lesioned.An open field test chamber was used to observe the spontaneous activity and the intake of food and water of mice during the daytime,night,and all day after unilateral Pe F-lesioned;The expression of MT m RNA in the paraventricular nucleus and suprachiasmatic nucleus of the Pe F-lesion mice was detected by RT-PCR.Results:(1)Retrospective study of fluorescent gold showed that fluorescent gold-labeled neurons were found in the Hi-CA1 region of mice 7 days after injection of fluorescent gold in the Pe F region.It is suggested that the mouse Hi-CA1 can emit nerve fiber projections to Pe F;at the same time,it was found that if the Hi-CA1 region was injected with fluorescent gold,fluorescent gold-labeled neurons were also found in the Pe F region of the mouse.It is suggested that the mouse Pe F brain neurons can also emit fibers to the Hi-CA1,that is,there is bidirectional fiber projection between Hi-CA1 and Pe F.(2)Compared with the sham lesion group,unilateral(left)Pe F lesion,total cell expression of orexin-A immunopositive in bilateral Pe F was significantly reduced(P<0.05);the percentage of ipsilateral lesion orexin-A immunopositive cells/ contralateral lesion orexin-A immunoreactive cells also significantly reduced(P<0.05).(3)Compared with the sham lesion group,there was no significant change in the locomotor activity,feeding and drinking water of the mice at 24 h(P>0.05).There was no significant change in locomotor activity,food intake and water intake during the day or night of Pe F-lesion mice(P>0.05).It is suggested that Pe F damage has no significant effect on the intrinsic behavior of mice during 24 hours of spontaneous activity,feeding and drinking.(4)In the sham lesion group,the locomotor activity,food intake,and water intake of the late dark(1:00–7:00)mice were significantly reduced compared with the early dark(19:00–1:00)(P<0.05);Compared with early dark(19:00–1:00)or late dark,The locomotor activity,food intake and water intake of the mice were further reduced in the early stage of light(7:00-13:00)or late in the light(13:00-19:00)(P<0.05).That is,when the mice in the sham lesion group enter the light period from the dark period,these activities are gradually reduced.In the Pe F lesion group,there was no significant change in spontaneous activity,food intake,and water intake in the late dark(1:00–7:00)mice compared with early dark(19:00–1:00)(P> 0.05),and these indicators are maintained at a high level throughout the dark period(19:00–7:00).However,compared with the dark period(including late dark and early dark),the spontaneous activity,feeding and drinking water of the mice during the light period(including early light and late light)were significantly reduced(P<0.05).Compared with the sham lesion group,the locomotor activity,feeding and drinking of the Pe F-lesion group showed a delay from night to night,especially from early dark to late dark.It is suggested that Pe F may be involved in the regulation of locomotor activity,feeding and drinking behavior in mice from night to light.(5)There was no significant change in the expression of MT m RNA in the paraventricular nucleus or suprachiasmatic nucleus of the mice in the sham lesion group at night(23:00-1:00)compared with the light phase(11:00-13:00)(P >0.05).However,in the Pe F-lesion group,compared with night phase(23:00-1:00),the expression of MT m RNA in the paraventricular nucleus and suprachiasmatic nucleus of the mice during the daytime(11:00-13:00)was significantly reduced(P<0.05).It is suggested that the delayed conversion of night to light induced by Pe F damage induced on locomotor activity,feeding and drinking in mice may be related to MT expression.Conclusions:There is a two-way fiber relationship between Pe F and Hi-CA1;Pe F damage has no significant effect on the intrinsic life behavior of mice during 24 hours of spontaneous activity,feeding and drinking;Pe F may be involved in the regulation of spontaneous activity,feeding and drinking behavior of mice in night to light;the delayed conversion of night to light induced by Pe F damage induced on locomotor activity,feeding and drinking in mice may be related to MT expression.