Stability of neuronal glial number in the aging mouse supraoptic nucleus.

The numbers of neurons and glia in the supraoptic nucleus were estimated in mice aged 6, 25, 28 and 31 months. There were no significant variations in the number of neurons or in the number of glia with age. Measurement of neuronal and glial nuclear diameters at 6, 12, 15, 22, 25, 28, and 31 months showed a steady decrease in neuronal nuclear diameter from 9.2 +/- 0.3 microns at 6 months to 8.3 +/- 0.1 microns at 22 months followed by an increase in diameter between 25 and 31 months to 9.8 +/- 0.1 microns. There was no significant variation in glial nuclear diameter (mean 6 microns) with age. Neuronal Nissl substance decreased with age but lipofuscin accumulation was not a prominent feature of ageing supraoptic neurons.