EARLY CYTOSKELETAL CHANGES AS SHOWN BY ALZ-50 ARE NOT ACCOMPANIED BY DECREASED NEURONAL-ACTIVITY

The nucleus tuberalis lateralis (NTL) is located in the basolateral pa rt of the hypothalamus and is only present as a well-delineated nucleu s in human and higher primates. In Alzheimer's disease (AD), NTL neuro ns show strong early cytoskeletal alterations, as revealed by the anti body Alz-50, but practically no senile plaques or neurofibrillary tang les. To study whether the activity of NTL neurons decreases when cytos keletal changes appear, i.e., during aging and in AD, we applied a pol yclonal antibody raised against the medial cisternae of the Golgi appa ratus (GA). The size of the GA and the cell profile of NTL neurons, tw o established parameters for neuronal activity, were measured by an im age analysis system. No significant change in the size of the profiles of the GA or of the neurons was observed in this nucleus during aging or AD. Earlier studies have shown that there is no decrease in cell n umber in the NTL in AD. We conclude that in the NTL an early hallmark of AD, i.e., cytoskeletal changes as stained by Alz-50, does not corre late with decreased neuronal activity, as reflected by the size of the GA, nor with a decrease in cell number. In addition, we found that th e very early occurring and abundant presence of lipofuscin in NTL neur ons does not go together with decreased neuronal activity.