Adaptation of mesenteric collecting lymphatic pump function following acute alcohol intoxication.

OBJECTIVE

Acute alcohol intoxication increases intestinal lymph flow by unknown mechanisms, potentially impacting mucosal immunity. We tested the hypothesis that enhanced intrinsic pump function of mesenteric lymphatics contributes to increased intestinal lymph flow during alcohol intoxication.

METHODS

Acute alcohol intoxication was produced by intragastric administration of 30% alcohol to conscious, unrestrained rats through surgically implanted catheters. Time-matched controls received either no bolus, vehicle, or isocaloric dextrose. Thirty minutes after alcohol administration, rats were anesthetized and mesenteric collecting lymphatics were isolated and cannulated to study intrinsic pumping parameters. In separate experiments, mesenteric lymphatics were isolated to examine direct effects of alcohol on intrinsic pump activity.

RESULTS

Lymphatics isolated from alcohol-intoxicated animals displayed significantly decreased CF compared to the dextrose group, elevated SVI versus all other groups, and decreased myogenic responsiveness compared to sham. Elevating pressure from 2 to 4 cm H₂O increased the volume flow index 2.4-fold in the alcohol group versus 1.4-fold for shams. Isolated lymphatics exposed to 20 mM alcohol had reduced myogenic tone, without changes in CF or SVI.

CONCLUSIONS

Alcohol intoxication enhances intrinsic pumping by mesenteric collecting lymphatics. Alcohol directly decreases lymphatic myogenic tone, but effects on phasic contractions occur by an unidentified mechanism.