Cardiac neuromodulation with acute intermittent hypoxia in rats with spinal cord injury

J Physiol, 2025 · DOI: 10.1113/JP287676 · Published: March 22, 2025

Spinal Cord Injury Cardiovascular Science Neurology

Simple Explanation

This study investigates the impact of spinal cord injury (SCI) on heart function in rats, focusing on the roles of the sympathetic and parasympathetic nervous systems. Researchers found that SCI-induced cardiac dysfunction is primarily due to impaired sympathetic control. The study also explores whether acute intermittent hypoxia (AIH), which involves exposing the rats to brief periods of low oxygen, can help improve heart function after SCI. Results indicated that AIH did enhance cardiac function in SCI rats. Through a series of experiments involving pharmacological blockades and AIH exposure, the study demonstrates that disrupted sympathetic pathways directly contribute to impaired heart function post-SCI, and AIH can effectively neuromodulate the heart in these conditions.

Study Duration

January and September 2022

Participants

Wistar rats (300–350 g)

Evidence Level

Not specified

Key Findings

1
Impaired direct sympathetic transmission to the heart underlies the majority of the SCI-induced reduction in heart function post-SCI.
2
Parasympathetic control remains unaltered post-SCI and does not contribute to reduced cardiac function post-SCI.
3
A single session of AIH is capable of neuromodulating the heart post-SCI, increasing left ventricular pressure generation and arterial blood pressure.

Research Summary

This study investigated the roles of the autonomic nervous system in cardiac dysfunction following spinal cord injury (SCI) in rats, finding that impaired sympathetic control is the primary driver. The research employed pharmacological blockades to dissect the contributions of sympathetic and parasympathetic pathways, revealing that parasympathetic control remains unaltered post-SCI. Acute intermittent hypoxia (AIH) was shown to neuromodulate the heart and enhance cardiac function in SCI rats, suggesting a potential therapeutic approach.

Practical Implications

Therapeutic Target

Adrenergic pathways are a focal point for therapeutic interventions.

Neuromodulatory Tool

AIH is an effective neuromodulatory tool for the cardiovascular system post-SCI.

Future Research

Further research is needed to examine the long-term effects and optimal protocols for AIH therapy in SCI.

Study Limitations

1
The sample included only male rats, which may not fully represent the effects in females.
2
The study was conducted in an anaesthetized preparation, which may influence autonomic responses.
3
Baseline differences between the AIH and TC groups for some cardiac indices.

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