Strain differences in brain alpha2- and beta-adrenergic receptor binding in dystrophic mice.

We have examined alpha 2-adrenergic [( 3H]-clonidine) and beta-adrenergic [( 3H]-dihydroalprenolol; DHA) binding in brain membranes from four different dystrophic mouse mutants: 129/ReJ-dy; 129 B6F1/J-dy; C57BL/6J-dy and C57BL/6J-dy2J. As shown previously, male 129/ReJ-dy mice have significantly fewer brain [3H]-DHA binding sites than their littermate controls. In marked contrast, the remaining three mutants showed no differences in [3H]-DHA binding when compared to their respective controls although there were inter-strain differences, e.g., C57BL/6J-dy2J mice have significantly fewer binding sites than the 129B6F1/J-dy mice. On the other hand, we saw no strain differences in alpha 2-binding. In one mutant, however, (129 B6F1/J-dy) we observed a 50% increase in alpha 2-binding sites compared to littermate controls. We conclude that weight loss or undernutrition may be an important factor in determining brain levels of adrenergic binding sites in dystrophic mouse brain.