LOW-DOSES OF ETHANOL REDUCE NEUROTENSIN LEVELS IN DISCRETE BRAIN-REGIONS FROM LS/IBG AND SS/IBG MICE

Studies were designed to examine the previously proposed hypothesis that some of the pharmacological actions of ethanol are mediated by neurotensinergic processes. Neurotensin‐immunoreactivity (NT‐ir) was extracted from various brain regions and shown by high performance liquid chromatography to possess the same retention time as authentic bovine NT1‐13. The highest levels of NT‐ir were observed in the hypothalamus with intermediate levels in the midbrain and striatum and lowest levels in the frontal cortex. Levels of NT‐ir were higher in hypothalamus and midbrain from long‐sleep (LS) than from short‐sleep (SS) mice. Ethanol, in vivo, produced a dose‐dependent decrease in NT‐ir in several brain regions; low doses, 1.5 to 3.0 g/kg, but not high doses, 4.1 g/kg, of ethanol significantly decreased NT‐ir in hypothalamus, midbrain, and striatum of LS and SS mice. Levels of NT‐ir in the frontal cortex were not altered by ethanol administration. Ethanol‐induced decreases in NT‐ir were of rapid onset with a maximum decrease in 5 min after intraperitoneal (i.p.) injection, and they were of long duration with levels remaining depressed for 4 hr. These findings show that subhypnotic, intoxicating doses of ethanol enhance NT release, in vivo, and support the hypothesis that some of ethanol's actions are mediated by neurotensinergic systems. Copyright © 1990, Wiley Blackwell. All rights reserved