title: [Effect of insulin on the myocardium of the active, hibernating and wakening ground squirrel Citellus undulatus].
abstract: The effect of insulin (0.1-100 nM) on isometric force of contraction in isolated ground squirrel papillary muscle was investigated. In summer, autumn and winter active animals, insulin had a negative inotropic effect on papillary muscles, decreasing the amplitude of contraction by about 30% of the control value. In some cases, predominantly in the summer group of animals, insulin produced different effects on contractility: low doses (0.1-0.5 nM) caused a transient activation of isometric contraction by about 10-15% of control, whereas high doses produced a negative inotropic effect by about 30% of the control level. During deep hibernation (at 5-6 degrees C of heart temperature) and during arousal from hibernation (from 3 to 20 degrees C), insulin had no significant effect on contractility. Opposite inotropic effects of insulin at concentrations of 0.1-50 nM were found during arousal: from 26 to 31 degrees C of heart temperature--a positive inotropic effect by about 20-25% of control, and from 32 to 36 degrees C--a negative one by about 30-40% of the control value.
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
authors.forename: O V
authors.initials: OV
authors.lastname: Nakipova
authors.forename: R Z
authors.initials: RZ
authors.lastname: Gaĭnullin
authors.forename: L A
authors.initials: LA
authors.lastname: Andreeva
authors.forename: V G
authors.initials: VG
authors.lastname: Safronova
authors.forename: L S
authors.initials: LS
authors.lastname: Kosarskiĭ
authors.forename: S G
authors.initials: SG
authors.lastname: Kolaeva
authors.forename: N G
authors.initials: NG
authors.lastname: Solomonov
authors.forename: N I
authors.initials: NI
authors.lastname: Kukushkin
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006605:Hibernation; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects; D010210:Papillary Muscles / Q000187:drug effects / Q000502:physiology; D012589:Sciuridae / Q000502:physiology*; D012621:Seasons; D014851:Wakefulness
chemical_list: D007328:Insulin