title: [The effect of insulin on circadian rhythm of voluntary locomotor activity in rats].
abstract: Effects of single intranasal administration of 0.2 ng insulin at different moments of the projected daily cycle (ZT = 1, ZT = 7, ZT = 13 and ZT = 19) on the circadian rhythms of voluntary locomotor activity (wheel-running) were studied in Wistar male rats. Insulin administered at ZT-7 or ZT-13 induced a statistically significant phase advance by 4.4 and 5.5 hours, respectively. The administration of insulin at ZT-13 additionally induced a reduction of the period of the circadian rhythm of voluntary locomotor activity. Intranasal administration of insulin at other moments of the projected daily cycle (ZT = 1 or ZT = 19) did not induce any statistically significant change in phase or period duration of the circadian rhythms. Insulin did not cause changes in total daily activity irrespective of administration time. The results of the study suggest the role of endogenous insulin as entrainment factor for circadian oscillator in absence of the main physiological zeitgeber--cyclic afferent input from retina photoreceptors.
authors.forename: A N
authors.initials: AN
authors.lastname: Iniushkin
authors.forename: K A
authors.initials: KA
authors.lastname: Mistriugov
authors.forename: D S
authors.initials: DS
authors.lastname: Gromova
authors.forename: E I
authors.initials: EI
authors.lastname: Pugachev
authors.forename: V I
authors.initials: VI
authors.lastname: Beliakov
authors.forename: E M
authors.initials: EM
authors.lastname: Iniushkina
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007328:Insulin