Effect of pre- and/or postganglionic nerve division on hydrocortisone-induced small intensely fluorescent cells in the rat superior cervical ganglion.

Daily hydrocortisone injections into newborn rats cause in a week about a 10-fold increase in the number of small intensely fluorescent cells in the superior cervical ganglion of the rat, as compared with untreated rats of the same age. The glucocorticoid-induced increase in the number of small intensely fluorescent cells is reversible. After discontinuation of the glucocorticoid treatment there is a significant decrease in the number of these cells during the 2nd postnatal week. The purpose of the present study was to investigate the significance of the innervation of the superior cervical ganglion on the fate of newly formed, hydrocortisone-induced small intensely fluorescent cells after discontinuation of the hydrocortisone treatment. Three-day-old rats were injected daily with hydrocortisone for 7 days. At the age of 10 days the pre- and/or postganglionic trunk(s) on one side were divided and the contralateral side served as control. Seven or thirty days after discontinuation of the hydrocortisone injections and the operation (i.e. at the age of 17 or 40 days) the rats were killed and the small intensely fluorescent cells were counted. The number of small intensely fluorescent cells, as expected, was greatly increased by the hydrocortisone injections. However, discontinuation of the treatment resulted in a decrease in the number of these cells in unoperated 40-day-old rats to a level, which is significantly less than the mean cell number/ganglion in totally untreated adult rats.(ABSTRACT TRUNCATED AT 250 WORDS)