Effect of acute ethanol intoxication on swallowing function in mice

Objectives

Ethanol consumption may lead to various symptoms depending on its concentration in the blood. Acute ethanol intoxication is a major risk factor for bolus -aspiration; however, studies on the effects of acute ethanol intoxication on swallowing are lacking. Therefore, we investigated the effect of acute ethanol intoxication on mice using the videofluoroscopic swallowing study (VFSS) methodology.

Methods

Male C57BL/6 J mice were randomly allocated into three groups: saline injection, 2 g/kg ethanol injection, and 4 g/kg ethanol injection. The VFSS technique was used to analyze the inter-swallow interval, lick-swallow rate, lick rate, bolus area, pharyngeal transit time, bolus speed, and bolus area 3 d before injection (control), 2 h after injection, and 8 h after injection.

Results

In the 4 g/kg ethanol injection group, the inter-swallow interval and lick-swallow rate increased after 2 h However, these changes were reversed 8 h after ethanol administration. Additionally, the pharyngeal transit time, bolus speed, and bolus area did not change significantly after ethanol administration.

Conclusions

The present study reveals that ethanol administration delays bolus transport in the mouth but does not affect pharyngeal swallowing reflexes and reflex thresholds. Acute ethanol intoxication specifically impairs the oral function as assessed by the VFSS.