The production of the norepinephrine metabolite 3-methoxy-4-hydroxyphethylenglycol (MHPG) in brain regions innvervated by the locus coeruleus was increased during naloxone-precipitated withdrawal from chronic morphine treatment. This MHPG increases was reversed by subcutaneous administration of clonidine. Changes in MHPG levels paralleled the electrophysiological changes found by Aghajanian (1978) in locus coeruleus firing rate with similar treatments, demonstrating the usefulness of MHPG changes as an index of central noradrenergic function.
- Locus coeruleus
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience