Amplitude-reduction and acrophase-advance of circadian mitotic rhythm in corneal epithelium of mice with bilaterally lesioned suprachiasmatic nuclei.
Powell-EW; Pasley-JN; Scheving-LE; Halberg-F
Anat Rec 1980 Jun; 197(2):277-281
The role of the suprachiasmatic nuclei in setting circadian body rhythms was assessed in relation to the rhythm of the mitotic index of mouse corneal epithelium. Electrolytic lesions of the suprachiasmatic nuclear area were performed in adult brown mice, and the animals were sacrificed at different times during the day (0800, 1200, 1000, 0000, or 0400 hours) after a post operative period ranging from 3 weeks to 3 months. Serial frozen sections of the brain were used to assess damage to the suprachiasmatic nuclei, which was correlated with mitotic figure counts for corneal epithelial preparations. Control animals included both unoperated and sham operated mice. The corneal epithelial preparations from unoperated animals showed a stable mitotic rhythm with a maximum of approximately 12 mitoses per 1000 cells at 0800 hours and a minimum approaching zero mitoses at 2000 hours. The sham operated controls showed a similar pattern. The operated animals showed a phase advance approximating 4 hours and an altered mitotic pattern with maxima between five and seven mitoses per 1000 cells at 0800 and 2000 hours and minima approaching four mitoses per 1000 cells at 1600 and 0000 hours. The mitotic index amplitudes for the lesioned and control mice were 0.11 and 0.54 respectively.
NIOSH-Publication; NIOSH-Grant; Psychological-disorders; Biological-rhythms; Endocrine-system; Microscopic-analysis; Cell-differentiation; Neuromotor-activity; Brain-damage; Laboratory-animals
Lab Medicine and Pathology University of Minnesota 380 Lyon Laboratories Minneapolis, MN 55455
Psychologic Disorders; Psychological-disorders
The Anatomical Record
University of Minnesota of Mnpls-St Paul, Minneapolis, Minnesota