Are chronic alcohol-induced central vasopressin changes determinant in strain dependency of tolerance in mice?

As vasopressin (VP) has been related to tolerance, we were interested in following central VP levels after chronic alcohol exposure of two selected mouse lines (C57Bl and Balb/c). Strongly elevated VP and VP mRNA levels have been noted, in particular in the hypothalamus. The phenomenon is much more marked in Balb/c mice than in C57Bl; in extrahypothalamic areas in the changes in VP noted in septum and amygdala are only apparent in Balb/c mice. Hypothalamic norepinephrine and serotonin, known to partly control VP release, also reacts in a strain dependent manner to alcohol. This study provides neurochemical evidence that long term ethanol intoxication selectively activates central vasopressinergic and aminergic neurons in mice. Such activation appears to be strain dependent; therefore it may be related to the unequal capacities of these strains to adapt to chronic alcohol intoxication. Such phenomena may partly account for differences between individuals in tolerance to chronic alcohol in men.