Volitional ethanol consumption affects overall serotonin metabolism in Syrian golden hamsters (Mesocricetus auratus)

Methods were established for the determination of serotonin (5-HT)(1) metab olites 5-hydroxyindole-3-acetic acid (B-HIAA) and 5-hydroxytryptophol (5-HT OL) in the urine of Syrian golden hamsters (Mesocricetus auratus) and used to study the effect of volitional ethanol. consumption on overall 5-HT meta bolism in this ethanol-preferring rodent. The basal levels of 5-HIAA and 5- HTOL in 24-h urine of ethanol-naive hamsters were 300 +/- 101 and 4.96 +/- 1.06 nmol (n = 8), respectively, Given free choice between water and a 15% ethanol solution, these hamsters chose to consume increasing amounts of eth anol. The increase was accompanied by a concomitant decrease in urine 5-HIA A and increase in urine 5-HTOL, indicating that volitional ethanol intake d iverted part of the 5-HT metabolic flux from an oxidative into a reductive pathway. In a separate experiment, the amounts of ethanol consumed by and b lood ethanol concentrations attained in ethanol-drinking golden hamsters we re determined at 5 different time intervals between 6 PM and 7 AM when most feeding activities occurred. Except in the first hour after lights were tu rned off, ethanol was consumed at a relatively even pace throughout the nig ht (2-3 g/kg/3 h) and blood ethanol levels were maintained at the low mM ra nge which rarely exceeded 2 mM. These results suggest that the biochemical pathway that catalyzes 5-HT metabolism is extremely sensitive to ethanol an d can play an important role in mediating the reported clinically beneficia l action of a low concentration of ethanol during alcohol detoxification. ( C) 2000 Academic Press.