Verapamil-induced changes in central conduction in patients with multiple sclerosis.

Area of Science:

• Neuroscience
• Pharmacology
• Clinical Neurology

Background:

• Demyelinated axons in multiple sclerosis (MS) exhibit altered electrophysiological properties, particularly sensitivity to plasma calcium levels.
• Calcium channel blockers may influence nerve impulse conduction in demyelinated pathways.

Purpose of the Study:

• To investigate the effect of verapamil, a calcium antagonist, on evoked potentials in multiple sclerosis (MS) patients.
• To assess if verapamil can modulate electrophysiological abnormalities in demyelinated axons.

Main Methods:

• Intravenous verapamil infusion in eight MS patients with abnormal evoked potentials and four healthy volunteers.
• Measurement of brainstem auditory evoked potentials (BAEPs) and visual evoked potentials (VEPs) before and during verapamil administration.
• Comparison of evoked potential parameters (peak latencies, interpeak intervals) between baseline and treatment.

Main Results:

• Verapamil significantly shortened prolonged latencies of BAEP peaks III and V in MS patients (p < 0.05).
• Interpeak intervals (I-III, III-V, I-V) of BAEPs and P100 latency of VEPs were also reduced in affected MS patients.
• Normal evoked potentials in MS patients and control subjects remained unchanged, indicating a specific effect on pathological pathways.

Conclusions:

• Intravenous verapamil acutely facilitates central conduction in some MS patients with demyelinated auditory and visual pathways.
• Pharmacological modulation of calcium-dependent processes at the axonal level may offer a strategy for managing MS-related conduction deficits.
• Findings suggest potential for verapamil in the acute management of conduction abnormalities in stable MS.