Neuromedins, smooth-muscle-stimulating peptides, are commonly divided into four groups:
bombesin-like, kassinin-like, neurotensin-like and neuromedins U. In the present review,
current data on the synthesis and mechanism of action of neuromedins on hypothalamo-pituitary-adrenal
(HPA) axis will be presented. These neuropeptides and their receptors are localized
to all components of the HPA axis, the only exemption seems to be neurokinin B, which
is not detected in the adeno-hypophysis. Neuromedins exert a manifold effect on HPA
axis, and their action on the adrenal suggests their involvement in the regulation
of growth, structure and function of the adrenal cortex. Neuromedins may exert both
direct and indirect effects on the adrenal cortex. Direct effect is proven by the
stimulation of mineralo- and glucocorticoid output by isolated or cultured adrenocortical
cells and by mobilisation of intracellular [Ca2+]i. Indirect effects, on the other hand, may be mediated by ACTH, arginine-vasopressin,
angiotensin II, catecholamines or by other regulatory substances of medullary origin.
Key words
Hypothalamus - Pituitary - Adrenal - Neuropeptides - Neurokinin A - Neurokinin B -
Neuromedin B - Neuromedin C - Neuromedin N - Neuromedin U
