Effects on dystrophic (dy/dy) limb muscle of the K+ channel blocker tetraethylammonium.
K(+) channel blockers, such as tetraethylammonium (TEA) and 4-aminopyridine, increase force of normal skeletal muscle. To determine whether they also increase force of diseased muscle, effects of TEA were examined on limb muscles of dy/dy dystrophic mice in vitro. TEA significantly increased isometric twitch force of normal and dystrophic soleus muscle by 29.9+/-5.8 and 30.0+/-5.0%, respectively, and significantly increased force of normal and dystrophic extensor digitorum longus muscle by 18.3+/-1.9 and 34. 9+/-10.4%, respectively. Force increases could be attributed only partially to a prolongation of contraction time. These data indicate that TEA augments force of overtly diseased (dystrophic) limb muscle to an extent comparable with that of normal limb muscle.
Manubay
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P
Departments of Medicine (Pulmonary) and Neurosciences, Case Western Reserve University and Cleveland VA Medical Center, Cleveland, OH 44106, USA.
van Lunteren
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E
D000818:Animals; D005121:Extremities; D007537:Isometric Contraction / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000503:physiopathology*; D009136:Muscular Dystrophies / Q000378:metabolism / Q000503:physiopathology*; D026902:Potassium Channel Blockers; D019789:Tetraethylammonium / Q000494:pharmacology*
D026902:Potassium Channel Blockers; D019789:Tetraethylammonium