Involvement of ghrelin in nucleus tractus solitaries on gastric signal afferent and gastric motility in cisplatin-treated rats.

OBJECTIVE Ghrelin had been known to promote gastric motility in human and animals previously. We aim to investigate the role of ghrelin in chemotherapy-induced nausea and vomiting. MATERIALS AND METHODS In the present study, we observed the changes in food intake, kaolin consumption, body weight, plasma ghrelin concentration and expression of ghrelin and its receptor GHS-R1a in the stomach and nucleus tractus solitaries (NTS) in cisplatin-treated rats, and the effects of ghrelin microinjected into NTS on the discharge activity of gastric distension (GD) responsive neurons and gastric motility were also observed. RESULTS Cisplatin induced the decrease in food intake and the increase in kaolin consumption of rats. In addition, mRNA expression of GHS-R1a in the stomach and NTS increased significantly after cisplatin treatment. The discharge activity of GD excited (GD-E) and GD inhibited (GD-I) neurons in cisplatin-treated rats was weaker than that of saline treatment, while ghrelin administration into NTS excited most of GD-E and GD-I neurons. Cisplatin induced the decrease in gastric contraction while ghrelin administrated into NTS promoted the gastric motility significantly. However, the amplitude and frequency of gastric contraction promoted by ghrelin in NTS of cisplatin-treated rats were lower than that of saline treated rats. The effects of ghrelin could be completely blocked by its receptor antagonist BIM28163. CONCLUSIONS These results indicated that ghrelin in the NTS might participate in the regulation of GD-neurons and gastric motility via its receptor in cisplatin-treated rats.