Determinants of active state in heart muscle: force, velocity, instantaneous muscle length, time.
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002415:Cats; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D009119:Muscle Contraction; D009638:Norepinephrine / Q000494:pharmacology; D010210:Papillary Muscles / Q000502:physiology*
D009638:Norepinephrine