SECRETORY AND STRUCTURAL EFFECTS OF 6‐HYDROXY‐DOPAMINE ON NORMAL PAROTID GLANDS OF RATS, AND AT DIFFERENT TIMES AFTER SURGICAL SYMPATHECTOMY

Abstract

The effects of i.v. 6-hydroxydopamine (6-OHDA), 100 mg/kg, were studied on parotid glands of rats at 12, 24, 48, 72 h and 3 wk after avulsion of the right superior cervical sympathetic ganglion. The salivary flow from normal left control glands and from right glands 12 h after ganglionectomy were similar, but at longer times after ganglionectomy the secretory response from the test glands was greatly reduced. Morphological assessment showed that 6-OHDA induced a massive depletion of secretory granules from all control glands and also at 12 h after ganglionectomy but at 48 and 72 h there was considerably less depletion of granules on the ganglionectomized side. At the longer times after ganglionectomy the secretion from the test glands is caused by circulating catecholamines released by the action of 6-OHDA on adrenergic nerves elsewhere, plus a possible small direct secretogogue effect of 6-OHDA. The additional effects on the normal side and at 12 h after ganglionectomy are thought to be attributable to the release of catecholamines from adrenergic nerves within the gland.