STRUCTURAL-CHANGES INDUCED BY CYTIDINE-5'-DIPHOSPHATE CHOLINE (CDP-CHOLINE) CHRONIC TREATMENT IN NEUROSECRETORY NEURONS OF THE SUPRAOPTIC NUCLEUS OF AGED CFW-MICE

The influence of chronic administration of cytidine-5'-diphosphate cho line (CDP-choline), a precursor of the membrane lipid phosphatidylchol ine, was studied in neurosecretory neurons (NSNs) of the supraoptic nu cleus (SON) of aged mouse hypothalamus. Animals were treated with CDP- choline from 12 months of age until 26 months. They were studied for b oth morphologic and morphometric features. The results obtained were c ompared to those of an age-matched control group. There was evidence o f differences between NSNs of the control group and those of the CDP-c holine group which showed neuronal hypertrophy. This size increase was mainly attributed to the increment of cellular protein synthesis mach inery, rough endoplasmic reticulum (RER) and Golgi complexes. Furtherm ore there was an increase in the number of neurosecretory granules (NS Gs) in the CDP-choline group. In addition, there were no tertiary lyso somes in the treated animals. Moreover, the percentage of NSN membrane that was not covered by glial prolongations, increased from about 2% in the control group to 12%, in the CDP-Choline treated group. These c hanges suggested an activation of the cellular processes for neurohorm one synthesis in the experimental group. Furthermore, these NSNs displ ayed lipid droplets in their cytoplasm. The possible relationship betw een CDP-choline and NSNs activity is discussed.