Riluzole and blood pressure in multiple system atrophy

Area of Science:

• Neuroscience
• Pharmacology
• Cardiovascular Physiology

Background:

• Multiple system atrophy (MSA) is a neurodegenerative disorder.
• Riluzole, a neuroprotective agent, is being investigated for MSA treatment.
• Riluzole's glutamate-antagonistic effects may impact the baroreflex, particularly in MSA patients with afferent pathway dysfunction.

Purpose of the Study:

• To evaluate the effect of a single 200 mg dose of riluzole on blood pressure and baroreflex sensitivity in patients with probable MSA.
• To investigate whether riluzole unmasks efferent baroreflex pathway effects in MSA patients.

Main Methods:

• A randomized, placebo-controlled study involving 10 probable MSA patients.
• Continuous monitoring of brachial blood pressure, heart rate, finger blood pressure, ECG, and cardiac stroke volume (impedance cardiography) for 120 minutes post-ingestion.
• Analysis of spontaneous baroreflex sensitivity and heart rate variability.

Main Results:

• Riluzole significantly increased blood pressure compared to placebo (16 +/- 6/10 +/- 2 mmHg vs. 5 +/- 5/2 +/- 3 mmHg, p < 0.001).
• Systemic vascular resistance increased by 32 +/- 6% with riluzole.
• No significant differences were observed in baroreflex sensitivity, heart rate variability, or systolic blood pressure variability between riluzole and placebo groups.

Conclusions:

• Riluzole induces a moderate pressor response in MSA patients, primarily due to increased systemic vascular resistance.
• This response may involve decreased inhibition of efferent sympathetic neurons.
• Riluzole's effect on baroreflex sensitivity was not evident in this MSA cohort.