Tugging force: A new objective index for evaluating acute changes in neuromuscular function in mice

• Published in: Journal of pharmacological and toxicological methods Vol. 76; pp. 23 - 26
• Main Authors: Okada, Shoichi, Orito, Kensuke
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2015
• Subjects: Animals; Biomechanical Phenomena - physiology; Grip strength; Male; Methods; Mice, Inbred ICR; Mouse; Muscle; Muscle relaxant; Muscle Strength - drug effects; Muscle Strength - physiology; Muscle Strength Dynamometer; Muscle, Skeletal - drug effects; Muscle, Skeletal - physiology; Neuromuscular Agents - adverse effects; Neuromuscular Agents - pharmacology; Neuromuscular Diseases - chemically induced; Neuromuscular Diseases - diagnosis; Neuromuscular function; Pancuronium; Suxamethonium; Tugging force; Vecuronium; Suxamethonium chloride dihydrate (PubChem CID: 656867); Vecuronium; Muscle relaxant; Pancuronium; Suxamethonium; Tugging force; Neuromuscular function; Pancuronium dibromide (PubChem CID: 27350); Mouse; Vecuronium bromide (PubChem CID: 39764); Muscle; Grip strength; Methods
• ISSN: 1056-8719; 1873-488X
• DOI: 10.1016/j.vascn.2015.07.003

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. 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. After administering the muscle relaxants suxamethonium, vecuronium, and pancuronium, the peak tugging force decreased maximally at 3 or 5min after administration, and recovered within 20min. These responses to the muscle relaxants were dose-dependent. Tugging force is an objective and reproducible parameter for examining the time course of an acute change in neuromuscular function.