Gastric vagal afferent inputs reach the glycemia-sensitive neurons of lateral hypothalamic area in the rat

The glycemia-sensitive neuron in lateral hypothalamic area (LHA) is one of the important central neural events involved in the feeding control. Electrophysiological studies have demonstrated that gastrointestinal vagal afferent inputs could convey the meal-related information of gastrointestinal tract to the hypothalamus. In this study, we examined whether the gastric vagal afferent inputs could reach the glycemia-sensitive neurons of the LHA by using in vivo extracellular recording technique in the rat. The results showed that stimulation of gastric vagal nerves elicited two types of the LHA neurons responses: the phasic response (93/116, 80.2%) and the change in cell’s firing pattern (23/116, 19.8%). Within the 93 cells that responded to the gastric vagal stimulation with a phasic response, 67 (72.0%) showed an inhibition in the cell’s firing rate, 26 (27.4%) were excited. Of the 23 cells that showed a change in the firing pattern, 13 responded to the gastric vagal stimulation with a long-lasting increase or decrease in firing rate, the remaining 10 cells turned their discrete spiking to the burst discharging. In addition, of 101 LHA neurons including the two types of responsive neurons, 73 (72.3%) were identified to be glycemia-sensitive neurons. These results demonstrated that the gastric vagal afferent inputs could reach the LHA and predominantly reach those glycemia-sensitive neurons in the LHA. Presumably, the modulation of glycemia-sensitive neurons of LHA by the gastric vagal afferent inputs may play an important role in the short-term regulation of feeding behavior. These two authors made equal contributions to this work.