Objective: The purpose of this study was to explore the effects and the corresponding mechanism. of espective central and peripheral secretin on discharge of gastrointestinal related neurons in Nucleus of tractus solitarius(NTS).  Methods:1.Spontaneous and electrostimulating subdiaphragmatic vagus nerve-induced discharge of the neurons in NTS was recorded in urethane - anesthetized rats. We investigated the effects of secretin on the electricity activity of the electrostimulating subdiaphragmatic vagus nerve related neurons in NTS by intravenous injection of different dosage of secretin (0.04, 0.08, 0.16μg·kg-1). 2. Spontaneous and gastric distention induced discharge of the neurons in NTS was recorded in urethane-anesthetized rats. The effect of secretin on electricity activity of gastric distention related neurons in NTS was investigated by intravenous injection of different dosage of secretin (0.04, 0.08, 0.16μg·kg-1) and rabbit’s secretin antiserum by us.3.Spontaneous and gastric distention induced discharge of the neurons in NTS was recorded in urethane -