title: Social interaction with a rhythmic rat enhances the circadian pattern of the motor activity and temperature of LL-induced arrhythmic rats.
abstract: Although light is the main factor that influences circadian rhythms, social interaction may also have a role on their regulation. Here, the influence of social interaction on rat circadian behavior was investigated, addressing the question of whether cohabitation would induce the appearance of a circadian rhythm in arrhythmic rats due to constant light. To this end, circadian rhythms of motor activity and body temperature of male and female LL-induced arrhythmic rats were studied before, during and after a 20-day period in which rats stayed in the same cage with a rat of the same sex but with stronger rhythm. Results showed that the manifestation of the circadian motor activity rhythm of LL-induced arrhythmic rats increased after cohabitation. In the case of the expression of the body temperature rhythm, there was a progressive daily increase in the power content of a daily 24 hour pattern throughout the cohabitation days, which remained when animals were again isolated. Thus, the presence of a rhythmic rat increases the strength of the circadian behavior of rats showing a weak circadian rhythm.
authors.affiliation: Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalunya, Spain. cambras@ub.edu
authors.forename: Trinitat
authors.initials: T
authors.lastname: Cambras
authors.forename: Lucía
authors.initials: L
authors.lastname: Castejón
authors.forename: Antoni
authors.initials: A
authors.lastname: Díez-Noguera
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001831:Body Temperature; D002940:Circadian Rhythm; D004195:Disease Models, Animal; D010505:Familial Mediterranean Fever / Q000209:etiology / Q000523:psychology* / Q000628:therapy*; D005260:Female; D007398:Interpersonal Relations; D008027:Light / Q000009:adverse effects; D008029:Lighting / Q000009:adverse effects; D008297:Male; D009043:Motor Activity; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013696:Temperature