Sympathetic neural control of indoleamine metabolism in the rat pineal glandThe mechanisms responsible for the acceleration in rat pineal biosynthetic activity in response to prolonged exposure to darkness or to immobilization were investigated in animals whose pineals were surgically denervated. Some animals were adrenalectomized to remove one potential source of circulating catecholamines, and some were subjected to a partial chemical sympathectomy accomplished by a series of intravenous injections of 6-hydroxydopamine. Results suggest that N-acetyltransferase (NAT) activity can be enhanced either by release of norepinephrine from sympathetic terminals within the pineal or from sympathetic nerve terminals elsewhere. The stress of immobilization stimulates the pineal by increasing circulating catecholamines. Photic control of pineal function requires intact pineal sympathetic innervation, since the onset of darkness apparently does not cause a sufficient rise in circulating catecholamines to stimulate the pineal. The present studies suggest that nonspecific stress triggers increased biosynthesis and secretion of melatonin; it is possible that this hormone may participate in mechanisms of adaptation.
Document ID
19760059432
Acquisition Source
Legacy CDMS
Document Type
Other - Collected Works
Authors
Lynch, H. J. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Hsuan, M. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Wurtman, R. J. (MIT Cambridge, Mass., United States)