Julian E Dilley, Emily Nicholson, Robin Zimmer, Janice C. Froehlich, Stephen M. Fischer
It is widely assumed that the amount of alcohol in the blood reflects the amount of alcohol consumed. However, several factors in addition to amount of alcohol consumed can influence blood alcohol concentration (BAC). The current study examines the effect of alcohol dose, concentration, and volume on BAC in rats with a high alcohol drinking (HAD) phenotype.
Study one examined the relationship between the amount of alcohol consumed and BAC. Alcohol-naïve, male, HAD rats (N=7) were given access to alcohol for 2 hrs/day for 9 consecutive days with food and water ad libitum. Alcohol intake and BAC were measured at 30, 60, and 90 minutes after onset of access. Study two examined the effects of altering alcohol dose, concentration, and volume on BAC (as measured by area under the curve). Alcohol-naïve, male, HAD rats (N=39) were infused, via an intragastric cannulus, with 1.16, 2.44, or 3.38 g alcohol/kg BW, produced by varying alcohol volume while holding concentration constant or by holding volume constant while varying concentration. Other rats were infused with 10%, 15%, or 20% v/v alcohol solutions while holding dose constant.
BAC was more strongly correlated with the ratio of alcohol intake (g/kg BW) to total fluid intake (mls) (R=0.85-0.97, p<0.05-p<0.001) than it was with the amount of alcohol consumed (g/kg BW) (R=0.70-0.81, p<0.05). No effect of alcohol dose was seen during the first hour following the onset of an alcohol infusion regardless of whether dose was achieved by altering alcohol volume or concentration. After one hour, higher alcohol doses were predictive of greater BACs.
The fact that a three-fold differences in alcohol dose did not result in significant differences in BACs during the first 30 minutes after ingestion of alcohol has potentially important implications for interpretation of studies that measure alcohol sensitive endpoints during this time.
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