Forebrain mechanisms in neurogenic hypertension

Area of Science:

• Neuroscience
• Cardiovascular Physiology
• Hypertension Research

Background:

• Forebrain structures are implicated in high arterial pressure (hypertension).
• The specific roles of supramedullary (above the medulla) brain regions in hypertension remain unclear.
• Selective aortic baroreceptor deafferentation (ABD) is a model used to study hypertension development.

Purpose of the Study:

• To identify the location and function of forebrain structures involved in hypertension following ABD.
• To determine the contribution of specific forebrain nuclei to the development and maintenance of elevated arterial pressure (AP).

Main Methods:

• Assessed metabolic activity in forebrain structures after ABD.
• Created bilateral electrolytic lesions in the paraventricular nucleus of the hypothalamus (PVH).
• Administered kainic acid (a neurotoxin) into the PVH.
• Performed electrolytic lesions of the subfornical organ (SFO).

Main Results:

• Elevated AP after ABD correlated with increased metabolic activity in the PVH, SFO, and other forebrain areas.
• Lesions or kainic acid treatment in the PVH prevented or reversed hypertension post-ABD.
• Lesions in the SFO attenuated the rise in AP following ABD.

Conclusions:

• The PVH and SFO are critical components of a neural circuit regulating AP after ABD.
• The SFO appears to influence AP by acting through the PVH.