Central Noradrenergic Pathways for the Integration of Hypothalamic Neuroendocrine and Autonomic Responses

Immunohistochemical and axonal transport methods were used to describe the organization of a series of central noradrenergic pathways that interrelate the nucleus of the solitary tract, which receives primary visceral sensory information, and the paraventricular and supraoptic nuclei of the hypothalamus, which participate in autonomic and neuroendocrine modes of homeostatic control. The results indicate that pathways arising from noradrenergic cells in the dorsal vagal complex, the ventrolateral medulla, and the locus coeruleus end in specific subdivisions of the paraventricular and supraoptic nuclei which are involved in the regulation of responses from the pituitary gland and from both divisions of the autonomic nervous system. This circuitry may play an important role in the integration of hypothalamic responses to visceral stimuli.