| Objective:To investigate the the nesfatin-1 nerve pathway between arcuate nucleus(ARC)-the amygdala(BMA)and the effects of this pathway on the firing activity of gastric distension(GD)-sensitive neurons and gastric motilityMethods:The nesfatin-1 nerve pathway between ARC-BMA was observed by retrograde tracing combined with immunohistochemical staining;The effects of nesfatin-1 on the discharge activity of GD neurons were observed by extracellular discharge recording;To investigate the effect of electrical stimulation of ARC on the discharge activity of GD neurons in BMA via electrical stimulation ARC nuclei and microinjection of nesfatin-1 antibodies into ARC;In vivo gastric motility study to investigate potential mechanism of the nesfatin-1 nerve pathway between ARC-BMA on gastric motility and gastric emptying.Results:(1)Fluorescent gold retrograde tracing combined with fluorescence immunohistochemistry staining showed that nesfatin-1/ fluorogold(FG)dual labelled neurons were detected in the Arc after injection of FG into BMA for 7 days,which inferred that some nesfatin-1 immunoreactive neuronal projections from Arc to BMA.(2)Electrophysiological experiments showed that there are GD neurons in BMA,62(62/106,58.5%)of which were identified as GD-E neurons,and 44(44/106,41.5%)were identified as GD-I neurons.After injection nesfatin-1 into BMA,the frequency of GD-E neurons in BMA increased(P<0.05)and the frequency of GD-I neurons decreased(P<0.05).Pre-injection of melanocortin receptor antagonism SHU9119,the effect of nesfatin-1 on the discharge of GD neurons was partially blocked(P<0.05),injection of SHU9119 into BMA alone had no effect on the activity of the GD-responsive neurons(P>0.05).(3)After electrical stimulation of ARC,the discharge frequency of nesfatin-1-responsive GD-E neurons increased in the BMA(P<0.05).Pre-treatment with an anti-NUCB2/nesfatin-1 antibody in the BMA,following electrical stimulation of the Arc,the frequency of GD-I neurons in BMA increased(P<0.05)and the frequency of GD-E neurons decreased(P<0.05).Injection of anti-NUCB2/nesfatin-1 anti-body into the BMA alone did not change the firing activity of the nesfatin-1-responsive GD neurons(P>0.05).(4)Results of in vivo gastric motility showed that injection of different doses of nesfatin-1(0.04μg,0.4μg,4.0 μg)to the BMA markedly decreased the amplitude and frequency of the gastric contractions in a dose-dependent manner(P<0.05-0.01).Aministration of the mixture of 0.4 μg nesfatin-1 + 0.20 μg SHU9119 could attenuate the inhibitory effect of nesfatin-1 on gastric contractile frequency and contraction amplitude(P<0.05).When given SHU9119 or normal saline alone into the BMA,the amplitude had no change(P>0.05).(5)The amplitude and frequency of gastric contraction increased after electrical stimulation of the Arc(P<0.05).After administration of an anti-NUCB2/nesfatin-1 antibody into the BMA,the Promoting effect induced by electrical stimulation of the Arc was further enhanced(P<0.05).Normal rabbit serum or anti-NUCB2/nesfatin-1 antibody alone had no significant effect on the gastric motility.(6)Gastric emptying experiments showed that injection of different doses of nesfatin-1(0.04μg,0.4μg,4.0 μg)can significant reduced the gastric emptying(GE),and shoe a dose-dependently relationship(P<0.05-0.01).Administration of the mixture of 0.4 μg nesfatin-1 + 0.20 μg SHU9119 into the BMA could weak the inhibitory effect of nesfatin-1 on gastric emptying(P<0.05).Conclusion:The nesfafin-1 pathway between ARC-BMA can regulate the activity of gastric stretch sensitive neurons and gastric motility in rats,and this effect may be related to the melanin signaling pathway... |
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