CRF-CONTAINING NEURONS IN THE HYPOTHALAMIC PARAVENTRICULAR NUCLEUS - REGULATION, ESPECIALLY BY CATECHOLAMINES

The neurons in the paraventricular nucleus that contain corticotropin-releasing factor (CRF) are regulated by humoral and neural inputs. Considerable evidence suggests that glucocorticoids act directly on these neurons to decrease their production of CRF. The paraventricular nuclei contain many peptides in addition to CRF and many different transmitters are found in afferent neurons that converge on them. These afferents include neurons from the subfornical organ that contain angiotensin II, neurons from the septum and elsewhere that contain enkephalin and substance P, neurons from the mesencephalon that contain serotonin, and neurons from the medulla oblongata that contain norepinephrine and epinephrine. The effects of catecholamines on CRF secretion remain controversial. Unilateral section of ascending norepinephrine-containing neurons leads to an ipsilateral decrease in paraventricular CRF content. However, there is appreciable evidence that epinephrine-containing neurons inhibit CRF secretion. A reasonable working hypothesis to explain the conflicting data is that there is a dual control: norepinephrine release from ascending neurons stimulates CRF secretion whereas epinephrine release inhibits CRF secretion.