Effect of short pulse gastric electrical stimulation on the c-fos expression in nucleus tractus solitarius and hypothalamus and its possible mechanism

Objective To investigate whether enteric nervous system(ENS)involve in mediating the effect of short pulse gastric electrical stimulation on c-fos expression in nucleus tractus solitarius (NTS)and hypothalamus.Methods Fifteen Wistar rats were divided into control group,gastric electrical stimulation(GES)group and ENS free group with 5 rats each.A pair of electrodes was implanted on the gastric serosa.In ENS free group,0.5%benzalkonii chloridum was applied on the serosa during the surgery.A set of short pulse GES with frequency of 20 cpm,pulse width of 300 μs and amplitude of 2 mA was applied via the electrodes for 30 rain in the stimulation group and ENS free group.The c-fos expression in NTS/hypothalamus was detected 1 h after the stimulation.Results The number of neuron with c-fos expression was(71.6±7.4)/HP in NTS group and(63.4±10.8)/HP in ENS free group,both were significantly higher than those in control group(36.4±8.6/HP,P＜0.05).The number of neuron with c-fos expression in hypothalamus was higher in GES[(224.2±47.3)/HP]and ENS free groups[(249.1±44.0)/HP]compared with control group[(90.2±47.3)/HP,P＜0.05].There was no significant difference in c-fos expression in NTS/hypothalamus between GES group and ENS free group(P＞0.05).Conclusions Short pulse gastric electrical stimulation significantly increases c-fos expression in NTS/hypothalamus,which suggests that NTS/hypothalamus may participate in mediating the effect of GES on gastric function.This effect may be not mediated by ENS. Key words: Enteric nervous system; ElectricaI stimulation CentraI nervous system