Analysis of intestinal cell proliferation after guanethidine-induced sympathectomy. I. Stathmokinetic, labelling index, mitotic index, and cellular migration studies.

Guanethidine-induced sympathectomy in the rat during the neonatal period (injection of 20 microgram/g body weight every 48 h from day of birth until day 14) produces an absolute reduction in the number of sympathetic ganglion cells, but no significant alteration of body weight. Superior cervical ganglia show 79.8% fewer cell bodies at 15 days and 92.3% at 45 days; coeliac ganglia exhibit an 81.0% reduction at 15 days and 89.6% at 45 days in guanethidine-treated rats as compared to normal controls. The sympathetic ganglion cells that remain after treatment have an abnormal morphological appearance with distended mitochondria and depletion of endoplasmic reticulum. Sympathectomy produces a prolongation of the generation cycle time (Tc) as measured by the colchicine-induced mitotic arrest technique, and a decrease in labelling, mitotic, and migration indices. In addition, sympathectomy suppresses the amplitude of the circadian rhythm in mitotic activity. The general suppression of this activity in the intestinal epithelium is more pronounced in the jejunum and ileum than in the duodenum. Variation in the effectiveness of sympathectomy on the inhibition of intestinal cell proliferation may be related to segmental differences in cell proliferation, to segmental differences in innervation, and/or to segmental variation in the effectiveness of guanethidine.