Anteroventral third ventricle periventricular tissue contributes to cardiac baroreflex responses

1. The studies reviewed in the present paper demonstrate that the anteroven tral 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 direc tly tested, this neurotransmitter is a good candidate for control of heart rate because noradrenaline in the AV3V region is critical for mediating oth er 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 sensiti vity by circulating substances, possibly acting at the organum vasculosum l amina terminalis. 4.The findings extend the role of the AV3V periventricular tissue as a cent ral site integrating autonomic nervous system function by demonstrating tha t this brain area contributes to cardiac function, in addition to its well- characterized role in sympathetic nervous system regulation of blood pressu re and mechanisms of fluid and electrolyte regulation.