Effects of chemical sympathectomy on mucus secretion by surface goblet cells from rat colon

The authors examined the effects of 6-hydroxydopamine (60HDA), the beta adrenergic agonist isoproterenol (ISO) and normal saline (NS) diluent on baseline mucus secretion from rat colonic goblet cells. Mucus secretion was evaluated by labeling mucin granules with /sup 3/H-glucosamine (10 ..mu..Ci/g BW). All rats were sacrificed at 2 or 4 hrs after administration of either 60HDA (100 mg/kg), ISO (100mg/kg) or NS. Samples of colon were fixed and processed for microscopy. Sections were mounted, stained, dipped in photographic emulsion and exposed for 3-5 wks. Rates of mucus synthesis and secretion were determined by scoring each favorably oriented surface goblet cell for the maximal apical translocation of labeled granules from cell base (1) to apical surface (7). Means and S.D. (N=50) were determined for each treatment group. Non-sympathectomized control rats treated with ISO showed a highly significant decrease in mucus secretion at both 2 and 8 hrs after dosing (p<0.001). Rats pretreated with 60HDA at time 0 and 5 days prior to sacrifice showed decreased mucus section at 2 hours and increased secretion at 4 hrs after dosing (p<0.001). A highly significant difference in mucus secretion was observed between 2 and 4 hr scores for the time 60HDA group. Results ofmore » this study strongly suggest that baseline synthesis/secretion rates in goblet cells are under sympathetic control in the colon.« less