Use of Tyrosine or Foods to Amplify Catecholamine Release.

Abstract : This project examined the effects of supplemental tyrosine on catecholamine (CA) release and on various behaviors and brain functions thought to be mediated by CAs. It included studies on both human and experimental animals. The human studies focused on: development of a paradigm to produce short-term psychological stress in humans and evaluation of a treatment-- administration of the A.A. tyrosine--that may mitigate some of the adverse behavioral and cardiovascular consequences of such stress; establishment of a collaborative research program with USAF School of Aerospace Medicine to develop various nutritional and psychopharmacologic strategies to enhance performance in stressful environments. The animal studies focused on: developing a brain slice system in which tyrosine levels in the medium could affect release; examining the ability of supplemental tyrosine to suppress the neuro-chemical, behavioral and endocrine effects of experimental stress; determining whether particular stress situations altered plasma amino acid levels so as to affect tyrosine's availability to catecholaminergic neurons; determining whether tyrosine is toxic in doses that might be used to enhance CA release; setting up an isolated perfused retina experimental system in which tyrosine levels affect dopamine release from retinal amacrine cells; determining whether tyrosine-containing dipeptides constitute a useful source of circulating tyrosine.