Abstract
Serum hormone levels and turnover rates of dopamine (DA), norepinephrine
(NE) and epinephrine (E) in tissue of pontine midbrain, limbic caudate,
and hypothalamic structures were measured following intraventricular
injection of 20 microgram beta-endorphin. Turnover of DA was increased
in the locus coeruleus and in structures innervated by the nigrostriatal
and mesolimbic DA systems while it decreased in the posterior hypothalamus.
The NE turnover was reduced in the locus coeruleus and posterior
mediobasal hypothalamus. In all tissues examined, beta-endorphin
treatment had no significant effect on E turnover. Serum levels of
prolactin and corticosterone increased following beta-endorphin treatment
whereas LH, FSH and TSH levels decreased. The observed effects of
beta-endorphin on preoptic and hypothalamic DA and NE turnover rates
may explain these hormonal changes. The reduced NE turnover in the
locus coeruleus may be induced by increased DA turnover. The observation,
that NE turnover in structures innervated by locus coeruleus neurons
may go in different direction suggest that NE turnover is regulated
independently from the activity of locus coeruleus neurons, hence
that the regulation must occur at the terminals by a direct or indirect
interaction with endorphinergic neurons.
Users
Please
log in to take part in the discussion (add own reviews or comments).