The Role Of The Central Amygdaloid Nucleus In The Regulation Of Colonic Motility

neurons were recorded in pentobarbital anesthetized, paralyzed, and ventilated male rats.Ipsilateral median and peroneal nerve afferent stimulation (MNAS, PNAS) at 0.5, 1.0, 1.5, 2.0 mA (0.2 ms, 50 Hz) was delivered by one pair of platinum electrodes.Gastric distension (GD) was produced by air inflation of a latex balloon (20, 40, 60 mmHg, 20s).All of the spinal neurons in this study responded to GD. MNAS (1.5 mA, 10 s) increased background activity in 6 spinal neurons, decreased activity in 19 neurons and did not affect 15 neurons.PNAS (1.5 mA, 10 s) increased background activity in 12 neurons, decreased activity in 15 neurons, and did not affect 14 neurons.MNAS more frequently reduced background activity of spinal neurons with excitatory responses to GD than did PNAS (19/23 vs 11/24, P<0.05).PNAS was more likely to increase background activity of spinal neurons with low-threshold excitatory responses to GD (≤20 mmHg) than did MNAS (10/23 vs 1/18, P<0.05).MNAS and PNAS also suppressed excitatory responses to GD in 8/10 and 9/9 tested neurons, respectively.Spinal transection at the rostral C1 segment abolished responses to MNAS in 1/4 neurons but did not significantly affect responses to PNAS in 5/5 neurons.These data indicated that somatic afferent information from extremities modulated gastric afferent processing in T9-T10 thoracic spinal cord.Modulation most commonly did not require a supraspinal pathway.Somatic afferent stimulation might have a potential role in treatment of some gastric diseases.