title: The effect of different photoperiods in circadian rhythms of per3 knockout mice.
abstract: The aim of this study was to analyse the circadian behavioural responses of mice carrying a functional knockout of the Per3 gene (Per3(-/-)) to different light : dark (L : D) cycles. Male adult wild-type (WT) and Per3(-/-) mice were kept under 12-hour light : 12-hour dark conditions (12L : 12D) and then transferred to either a short or long photoperiod and subsequently released into total darkness. All mice were exposed to both conditions, and behavioural activity data were acquired through running wheel activity and analysed for circadian characteristics during these conditions. We observed that, during the transition from 12L : 12D to 16L : 8D, Per3(-/-) mice take approximately one additional day to synchronise to the new L : D cycle compared to WT mice. Under these long photoperiod conditions, Per3(-/-) mice were more active in the light phase. Our results suggest that Per3(-/-) mice are less sensitive to light. The data presented here provides further evidence that Per3 is involved in the suppression of behavioural activity in direct response to light.
authors: Departamento de Psicobiologia, Universidade Federal de São Paulo (UNIFESP), Rua Napoleão de Barros 925, 3 º Andar, 04024-002 São Paulo, SP, Brazil.
authors: D S
authors: DS
authors: Pereira
authors: Faculty of Health and Medical Science, University of Surrey, Guildford, UK.
authors: D R
authors: DR
authors: van der Veen
authors: Departamento de Fisiologia, Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN, Brazil ; Instituto Federal Sudeste de Minas Gerais, Campus Barbacena, Barbacena, MG, Brazil.
authors: B S B
authors: BS
authors: Gonçalves
authors: Departamento de Psicobiologia, Universidade Federal de São Paulo (UNIFESP), Rua Napoleão de Barros 925, 3 º Andar, 04024-002 São Paulo, SP, Brazil.
authors: S
authors: S
authors: Tufik
authors: Faculty of Health and Medical Science, University of Surrey, Guildford, UK.
authors: M
authors: M
authors: von Schantz
authors: Faculty of Health and Medical Science, University of Surrey, Guildford, UK.
authors: S N
authors: SN
authors: Archer
authors: Escola de Artes, Ciências e Humanidades, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors: M
authors: M
authors: Pedrazzoli
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D005260:Female; D008027:Light; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D056950:Period Circadian Proteins / Q000172:deficiency* / Q000378:metabolism; D017440:Photoperiod
chemical_list: C512645:Per3 protein, mouse; D056950:Period Circadian Proteins