Preoptic-hypothalamic periventricular lesions: thirst deficits and hypernatremia

Area of Science:

• Neuroscience
• Physiology
• Behavioral Science

Background:

• Thirst regulation is complex, involving multiple brain regions.
• The anteroventral third ventricle (AV3V) region is implicated in mediating thirst responses.

Purpose of the Study:

• To investigate the role of the AV3V in mediating thirst induced by hyperosmotic and angiotensin stimuli.
• To determine if lesions in the AV3V affect regulatory drinking behavior.

Main Methods:

• Electrolytic lesions were made in the periventricular tissue surrounding the AV3V in rats.
• Rats were tested for drinking responses to hypertonic NaCl, angiotensin, water deprivation, and hypovolemia.

Main Results:

• AV3V lesions resulted in adipsia and persistent drinking deficits to osmotic and angiotensin challenges.
• Lesioned rats showed reduced drinking after water deprivation and increased plasma osmolality.
• Drinking responses to hypovolemia and feeding behavior were unaffected by the lesions.

Conclusions:

• The AV3V periventricular tissue plays a critical role in mediating regulatory drinking behavior.
• Lesions likely impair drinking by destroying receptors or integrative systems for fluid-borne stimuli.