Lateral Parafacial Neurons Evoked Expiratory Oscillations Driving Neurogenic Hypertension

Area of Science:

• Neuroscience
• Cardiovascular Physiology
• Hypertension Research

Background:

• Hypertension is a major cardiovascular risk factor with poor control in 40% of treated patients.
• Excessive sympathetic activity is implicated as a key contributor to uncontrolled hypertension.
• Neuronal expiratory oscillations in the medullary lateral parafacial (pFL) region are hypothesized to be activated in neurogenic hypertension.

Purpose of the Study:

• To investigate the role of pFL neuronal activity in neurogenic hypertension.
• To determine if silencing pFL neurons exerts an antihypertensive effect.

Main Methods:

• pFL neurons were manipulated using optogenetics and pharmacogenetics in rats.
• Sympathetic activity, respiratory motor outputs, and arterial pressure were recorded in normotensive and hypertensive rats.
• Neurogenic hypertension was induced via chronic intermittent hypoxia.

Main Results:

• Activation of pFL neurons increased sympathetic activity and blood pressure.
• pFL neurons project to and excite RVLM and A5 presympathetic neurons.
• Inhibition of pFL neurons normalized arterial pressure in hypertensive rats by reducing sympatho-excitation.

Conclusions:

• Heightened sympathetic activity in hypoxia-induced hypertension involves pFL expiratory oscillations.
• pFL neurons drive RVLM and A5 sympathetic neurons, causing active expiration and hypertension.
• Suppression of pFL neurons demonstrates therapeutic potential for hypertension treatment.