Anteroventral third ventricle periventricular tissue contributes to cardiac baroreflex responses.

1. The studies reviewed in the present paper demonstrate that the anteroventral third ventricle (AV3V) region contains tissue that can modify cardiac baroreflex sensitivity in response to circulating angiotensin (Ang)II and hyperosmolality. 2. The response to hyperosmolality appears to be mediated by noradrenergic receptors. Although the role of noradrenergic receptors in the AV3V region in modification of baroreflex-induced responses to AngII has not been directly tested, this neurotransmitter is a good candidate for control of heart rate because noradrenaline in the AV3V region is critical for mediating other responses to AngII. 3. Results from studies indicate that the AV3V region is part of a central nervous system circuit involved in modulation of cardiac baroreflex sensitivity by circulating substances, possibly acting at the organum vasculosum lamina terminalis. 4. The findings extend the role of the AV3V periventricular tissue as a central site integrating autonomic nervous system function by demonstrating that this brain area contributes to cardiac function, in addition to its well-characterized role in sympathetic nervous system regulation of blood pressure and mechanisms of fluid and electrolyte regulation.