Time course of the disappearance of pineal noradrenaline following superior cervical ganglionectomy.

Pineal glands were collected from superior cervical ganglionectomized (SCGX) and sham-treated rats at time intervals following surgical manipulation. Pineal noradrenaline (NA) levels were quantitated by a radioisotopic-enzyme technique, or the pineals were examined by histofluorescence or electron microscopic techniques. A significant decline in pineal NA content was observed by 12 hours with a virtual disappearance of NA by 24 hours following SCGX. The depletion of NA content correlated with the disappearance of synaptic vesicles and the appearance of generalized fine structural degeneration of the sympathetic nerve endings in the pineals. Then results indicate that less than one day is required to remove all of the potentially, functional neurotransmitter from the denervated pineal gland. These observations agree closely with the time course of degeneration of other sympathetic nerve terminals following SCGX.