THE MYENTERIC PLEXUS REGULATES CELL-GROWTH IN RAT JEJUNUM

The roles of the myenteric and extrinsic nerves in the control of proliferation and cell growth in the rat jejunum were studied. The myenteric plexus and/or the extrinsic nerves in a segment of rat jejunum were ablated by serosal application of the surfactant benzyldimethyltetradecylammonium chloride or by crushing the nerves passing through the mesentery, respectively. Ablation of both myenteric and extrinsic nerves, but not the extrinsic nerves alone, resulted in a significant increase in the mitotic rate of the crypt-epithelial cells and in the size of VIP-immunoreactive neurons in the submucosal plexus. The increased mitotic rate was correlated with an increase in the weight of the mucosa per unit length of gut and in the villus length and crypt depth. Neither extrinsic denervation alone nor serosal application of saline had any effect on these parameters. Our results suggest that the myenteric plexus is able to influence the rate of cell proliferation and cell growth in the rat jejunum.