Effects of γ-aminobutyric acid on feeding changes in rats and its potential mechanism / 中华行为医学与脑科学杂志

ABSTRACT

Objective@#To investigate whether γ-aminobutyric acid (GABA) receptor signaling pathway is involved in the regulation of thalamic undefined (ZI)-nucleus accumbens (NAc) neural pathways on gastric distraction (GD)-sensitive neuronal firing activity and the impact on food intake, the number of times and the frequency in rats.@*Methods@#Six rats were randomly selected and the neural pathway between ZI and NAc in rat thalamus was observed by fluorescent gold (FG) retrograde tracing method.Eighty-two rats were randomly selected, and the gastric balloon was placed in gastric cavity, the microelectrode was placed in the NAc, and the stimulating electrode was placed in the ZI. The single-cell discharge recording method was used to observe the effect of electrical stimulation ZI on the excitability of GD-sensitive neurons in rat NAc.Eighteen rats were randomly selected and were divided into three groups according to the random number table. They were NS group, GABA group, GABA + GABA receptor antagonist bicuculline (BIC) group with 6 in each group, and the rat NAc was used to embed the cannula. The method of GABA and BIC was injected to observe the changes of cumulative food intake in rats for 4 h. Eighteen rats were randomly selected and randomly divided into three groups sham stimulation (SS) group, 50 μA electrical stimulation group, 50 μA electrical stimulation + BIC group with 6 in each group. The 4 h cumulative food intake of rats was observed by electro-stimulation of rat ZI and rat NAc injection of BIC.@*Results@#Fluorescent gold retrograde tracking combined with fluorescent immunohistochemical staining showed that there were visible GABA and fluorescent gold double labeled neurons in ZI. Electrical stimulation of ZI, the frequency of GABA-sensitive GD neurons in rat NAc increased significantly (GD-E increase (78.8±8.4)%, GD-I increase (89.3±9.2)%, P<0.01), but the inhibitory effect was antagonized by BIC (GD-E increase (113.8±13.6)%, GD-I increase (121.8±14.2)%, P<0.01). Microinjection of GABA in rat NAc significantly increased the cumulative food intake for 4 h ((155.72±18.84) kcal, t=3.41, P<0.05), which was antagonized by partial BIC (123.43±15.11) kcal, t=3.28, P<0.05). Electrical stimulation of ZI significantly increased the food intake in rats ((39.07±11.27) kcal, t=2.96, P<0.05), and this effect can be partially antagonized by BIC ((34.17±10.85)kcal, t=2.33, P<0.05).@*Conclusion@#The ZI-NAc neural pathway regulates the discharge activity of rat gastric distension (GD)-sensitive neurons and the feeding status of rats, and the GABA receptor signaling pathway may be involved in mediating the process.