Chapter 7 - Tracking the Coupling of External Signals to Intracellular Programs Controlling Peptide Synthesis and Release in Hypothalamic Neuroendocrine Neurons

Abstract

Corticotropin-releasing hormone (CRH) neuroendocrine neurons of the paraventricular hypothalamic nucleus constitute the final common pathway for the hypothalamo–pituitary–adrenal axis. These neurons trigger an important cascade of hormone releasing events that allow the organism to respond adaptively to stress, including the release of CRH from the hypothalamus, adrenocorticotropic hormone from the anterior pituitary gland, and cortisol (corticosterone in rats) from the adrenal cortex. Despite the central place of CRH neuroendocrine neurons in this hierarchy, the precise manner by which stimuli engage the brain to drive these neurons remains unclear. In this chapter, we describe experiments establishing functional linkages among a peripheral stressor (glycemic challenge), hindbrain-originating neural circuits, and intracellular programs that control the synthesis and release of CRH neuropeptide. A model is presented based on these studies that offers a testable framework upon which to build, and extensions of these findings to larger brain networks are discussed.