Arginine vasopressin as a central neurotransmitter.

Anatomical and electrophysiological studies have revealed a widespread innervation of the brain by arginine vasopressin (AVP)-containing fibers. There is evidence that these central AVP pathways may be activated simultaneously with endocrine pathways. Stimulation of hypothalamic nuclei that contain AVP cell bodies causes changes in electrical activity of neurons in areas receiving AVP projections; in these same regions, release of immunoreactive AVP can be detected in response to appropriate stimuli or hypothalamic stimulation. These parts of the brain have also been shown to contain AVP receptors, and application of AVP to cells in these areas alters spontaneous activity or modifies the responses to other transmitters. AVP appears to act as a neurotransmitter involved in the central control of the cardiovascular, renal, and thermoregulatory systems. AVP may act centrally to coordinate autonomic and endocrine responses to homeostatic perturbations.