EFFECT OF CHRONIC ALCOHOL-CONSUMPTION ON THE HUMAN LOCUS-COERULEUS

Despite reduced levels of noradrenaline and increased cortical beta-ad renergic receptor binding, there is controversy regarding the effect o f chronic alcohol consumption on the noradrenergic neurons of the locu s coeruleus (LC). The aim of this study is to investigate the effects of chronic alcohol consumption on the LC; in particular, to determine whether or not there is any alteration in the size or number of neuron s, or other significant changes in this nucleus. Eight chronic alcohol ics without additional medical complications and eight age-matched con trols were selected for this study. Immunohistochemistry with antibodi es against tyrosine hydroxylase (TH) was used to visualize TH-positive neurons in spaced serial 50-mu m sections throughout the length of th e LC. These neurons were counted and no correction factors applied. Th ere was no significant loss of TH-positive neurons in the LC of alcoho lics compared with controls who had up to 20% variation in the number of neurons between individuals. This confirms published results from o ne alcoholic without complications, but contradicts recent findings of a significant neuronal loss in five alcoholics, all with liver pathol ogy. Our analysis suggests that central noradrenergic neurons in alcoh olics without significant medical complications are not susceptible to alcohol neurotoxicity.