Effect of Lithium Upon Circadian Rhythm of Locomotor Activity in Gerbil Meriones ungiculatus: Gender Differences

Efeito do Litio sobre o Ritmo Circadiano  na Atividade Locomotora do Gerbil Meriones unguiculatus: Diferenças Sexuais

Juárez-Tapia Cinthia Rocío, Miranda-Anaya Manuel,  Moreno-Sáenz Enrique, Durán Pilar *

ABSTRACT

The effect of lithium on  circadian  rhythms has  been  studied  to  understand  whether affective and  bipolar disorders  are  related  to disturbances  on  the  circadian   regulation.   Some  species  of  Gerbils  (sand  rat, Mongolian gerbil) have been proposed  as a model to study mood disorders. The aim of the present work was to study the effects of chronically ingested lithium upon the structure of locomotor activity in male and female gerbils exposed to constant conditions as well as light/dark cycles; in order to understand  if the free running period  and activity levels and  phase  relationship  with a  light cycle is affected  by chronic  lithium chloride administration in water. Locomotor activity was recorded  from individual gerbils, by means of running wheels coupled   to  infrared  light  beams   in  environmental   controlled   chambers.  Results  obtained   indicate   a lengthening of the free running period   and activity phase  in males, but an opposite effect in females until 20 days after beginning the ingest of LiCl,  therefore its effects upon circadian  free running period was different regarding the gender.

Key words: circadian, locomotor activity, Mongolian gerbil, lithium, gender.