Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

The aim of the present study was to lower plasma concentrations of tyrosine, the amino acid precursor of noradrenaline and to determine whether this manipulation impaired noradrenergic function as measured by the evening rise in concentrations of plasma melatonin. Eight healthy volunteers received three drinks: (i) an essential amino acid load with tyrosine, (ii) the same load without tyrosine and its precursor, phenylalanine and (iii) tap water. The tyrosine- and phenylalanine-deficient drink lowered plasma tyrosine by approximately 50% over 5 h. However, this did not alter the evening plasma melatonin levels compared to the other two drinks. The results suggest that amino acid loading produces a modest decline in plasma tyrosine levels but this does not lower noradrenergic neurotransmission in the pineal gland.

Original publication

DOI

10.1177/026988119601000309

Type

Journal article

Journal

J Psychopharmacol

Publication Date

01/1996

Volume

10

Pages

231 - 234