Stress-related inputs converge upon the neurons of the medioparvocellular division of the PVN. These cells release CRH and other secretagogues into the portal plasma, which are then carried to the anterior pituitary, stimulating the synthesis and release of ACTH (and other POMC-derived peptides) from corticotropes into the systemic circulation. These events culminate in the ACTH-induced release of glucocorticoids from the adrenal cortex. Glucocorticoids exert inhibitory feedback effects at multiple levels, including the pituitary, PVN, and other brain sites, possibly including the hippocampus. Hippocampal effects on the PVN may be mediated through neuronal relays, including the BST and various hypothalamic nuclei. Abbreviations: BST, bed nucleus of the stria terminalis; CRH, corticotropin-releasing hormone; PVN, hypothalamic paraventricular nucleus. Drawing courtesy of W. E. Cullinan.
|Back to Chapter|