title: [Effects of interleukin-2 on ventricular papillary muscle of rat and the possible mechanism].
abstract: OBJECTIVE
  To investigate the effects of interleukin-2 (IL-2) on the transmembrane potential and contractile force in ventricular papillary muscle of rat and the underlying mechanism.
  
  
  METHODS
  The transmembrane potentials and contractile force were recorded by intracellular glass microelectrode and tension transducer in the isolated rat papillary muscles.
  
  
  RESULTS
  (1) IL-2 shortened the action potential duration (APD50 and APD80), while had no effects on resting potential, action potential amplitude and depolarization rate. (2) IL-2 depressed the contractile force of the muscle in dose-dependent manner. IL-2 at concentrations of 0.5, 2.5, 10, 50 and 200 u/ml decreased the developed tension to 94.8% (P < 0.05), 85.8%, 76.3%, 69.3% and 52.5% (P < 0.01), respectively. (3) Pretreatment with L-NAME (10(-4) mol/L) attenuated the negative inotropic effect of IL-2, in which effect of IL-2 at concentrations from 0.5 to 10 u/ml was completely abolished, and the effect of IL-2 at high dose (50 and 200 u/ml) was partly attenuated by L-NAME.
  
  
  CONCLUSIONS
  IL-2 had inhibitory effects on action potential duration and contractile force of papillary muscle, and its negative inotropic effect was mediated by nitric oxide.
authors.affiliation: Department of Physiology, Zhejiang University School of Medicine, Hangzhou 310031, China.
authors.forename: Guo-hua
authors.initials: GH
authors.lastname: Lin
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xia
authors.forename: Yue-liang
authors.initials: YL
authors.lastname: Shen
mesh_terms: D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D006352:Heart Ventricles / Q000187:drug effects; D007376:Interleukin-2 / Q000494:pharmacology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D010210:Papillary Muscles / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D007376:Interleukin-2; D009569:Nitric Oxide