DIURNAL RHYTHM OF NUCLEOLAR VOLUME IN SYMPATHETIC NEURONS OF THE RATSUPERIOR CERVICAL-GANGLION

  • 1 January 1981
    • journal article
    • research article
    • Vol. 24  (1) , 128-130
Abstract
Rhythmic variations of nucleolar volume in neurons from the superior cervical ganglion were studied in rats under artificial synchronization (light: 0700-1900 h; dark: 1900-0700 h) with free access to food and water. Groups of 3 animals were sacrificed by intracardiac perfusion every 4 h during the 24-h period and every 2 h between 2200 and 0700 h. The mean nucleolar volume (.hivin.Vnu) was estimated in the SCG [superior cervical ganglion] neurons of each group by measuring the surface area of 450 semi-thin nucleolar sections using a camera lucida and a semi-quantitative analyzer. Stereological analysis demonstrated that variations in .hivin.Vnu followed a normal curve distribution according to the time of sacrifice, the maximum .hivin.Vnu being found during the dark between 00 and 01 h. During the 24-h period the .hivin.Vnu (.+-. SE), which was low at 14-15 h (6.451 .+-. 0.540 .mu.m3), increased 2-fold to reach a maximum value (13.443 .+-. 0.705 .mu.m3) at 00-01 h, and then decreased to its nadir at 14-15 h on the following day.

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