At 2:00 a. m. the nurse on duty was called to the patient's room. The patient had vomited a large quantity of undigested food. He was perspiring profusely, his pulse was 132 beats/min, and his blood pressure was 215/138 mmHg. An abdominal exam showed no evidence of tenderness, but there was a complete lack of bowel sounds. Over the next hour the patient's pulse slowed, blood pressure fell toward normal, and he was able to go back to sleep until morning. Blood and urine tests in the morning showed normal blood glucose, but a significant elevation of urinary glucose. Which of the following is a normal stimulator of digestive activity?

Sympathetic nerve activity

Increased insulin secretion

Decreased thyroid hormone

Decreased cortisol secretion

Parasympathetic nerve activity