title: Tugging force: A new objective index for evaluating acute changes in neuromuscular function in mice.
abstract: BACKGROUND
  Many agents, including muscle relaxants, influence neuromuscular function. Although in vitro and in situ measurement systems of skeletal muscular contractility have been developed and in use for years, no convenient device and parameter are available to examine the time course of the acute effects of such agents on neuromuscular function in conscious mice.
  
  
  METHODS
  We created a two-compartment device consisting of a transparent, wide, acrylic chamber with a foot shock grid, and an attached, opaque narrow tunnel to measure neuromuscular performance. A mouse placed into the wide chamber, quickly enters the narrow tunnel. We attached a string to the tail of the mouse to measure the developed tugging force when the mouse entered the narrow tunnel.
  
  
  RESULTS
  After administering the muscle relaxants suxamethonium, vecuronium, and pancuronium, the peak tugging force decreased maximally at 3 or 5 min after administration, and recovered within 20 min. These responses to the muscle relaxants were dose-dependent.
  
  
  CONCLUSIONS
  Tugging force is an objective and reproducible parameter for examining the time course of an acute change in neuromuscular function.
authors.affiliation: Laboratory of Physiology II, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Okada
authors.affiliation: Laboratory of Physiology II, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan. Electronic address: oritok@azabu-u.ac.jp.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Orito
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology*; D008297:Male; D008813:Mice, Inbred ICR; D053580:Muscle Strength / Q000187:drug effects* / Q000502:physiology; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D009465:Neuromuscular Agents / Q000009:adverse effects / Q000494:pharmacology*; D009468:Neuromuscular Diseases / Q000139:chemically induced / Q000175:diagnosis
chemical_list: D009465:Neuromuscular Agents
keywords: Grip strength; Methods; Mouse; Muscle; Muscle relaxant; Neuromuscular function; Pancuronium; Pancuronium dibromide (PubChem CID: 27350); Suxamethonium; Suxamethonium chloride dihydrate (PubChem CID: 656867); Tugging force; Vecuronium; Vecuronium bromide (PubChem CID: 39764)