Effects of baclofen on swallow motor pattern.

Area of Science:

• Neuroscience
• Pharmacology
• Physiology

Background:

• Baclofen is a GABA_B receptor agonist used to treat spasticity.
• Baclofen has been linked to prolonged mechanical ventilation and aspiration pneumonitis.
• The drug's effects on the pharyngeal swallow reflex, a key airway protective mechanism, are not fully understood.

Purpose of the Study:

• To investigate the effects of baclofen on the pharyngeal swallow reflex in anesthetized cats.
• To determine if baclofen administration alters the electromyographic (EMG) activity of muscles involved in swallowing.

Main Methods:

• Electromyography (EMG) was used to record muscle activity in four spontaneously breathing cats under sodium pentobarbital anesthesia.
• Swallowing was induced by oral water infusion before and after administering two doses of baclofen (3 µg/kg and 10 µg/kg).

Main Results:

• Baclofen administration led to increased thyrohyoid EMG amplitude.
• Parasternal EMG amplitude decreased after the 3 µg/kg baclofen dose.
• While other muscle activations showed an average increase, significance was not reached.

Conclusions:

• Baclofen may alter the muscular coordination of the pharyngeal swallow reflex.
• Increased thyrohyoid activation could prolong laryngeal abduction, and decreased parasternal activation may impede negative intrathoracic pressure generation.
• These findings suggest a potential increased risk of aspiration with baclofen use, warranting further investigation into its effects on airway protection.