Effects of intergeniculate leaflet lesions on circadian rhythms in the mouse.
We investigated effects of bilateral electrolytic intergeniculate leaflet (IGL) lesions (IGLX) on circadian rhythms of the wheel-running activity in mice kept under constant darkness conditions (DD). As a result of complete bilateral IGL lesions, the period of a free-running rhythm was lengthened by ca. 45 min in comparison with a pre-operational one. The present findings confirm results obtained previously with other animals. However, for the first time locomotor activity levels were precisely assessed in mice (the number of wheel revolutions/day) before and after IGL lesions. A computer analysis of data showed a considerable decrease in that activity (by 68% on an average) in mice with complete bilateral IGL lesions in comparison with IGL-non-lesioned individuals. The obtained results show that also in mice IGL constitutes an anatomically important element of the mechanism of a circadian time-keeping system, which mediates the transfer of non-photic information to the suprachiasmatic nuclei (SCN) by modulating their activity.
Lewandowski
Marian H
MH
Department of Animal Physiology, Institute of Zoology, Jagiellonian University, R. Ingardena St. 6, 30060 Cracow, Poland. lew@zuk.iz.uj.edu.pl
Usarek
Artur
A
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D003624:Darkness; D005829:Geniculate Bodies / Q000502:physiology*; D051379:Mice; D009043:Motor Activity / Q000502:physiology