Relaxin restores altered ileal spontaneous contractions in dystrophic (mdx) mice.
We studied the effects of relaxin on ileal contractility in normal and dystrophic (mdx) mice. Ileal preparations from male normal and mdx mice showed spontaneous myogenic contractions whose amplitude was significantly higher in the latter ones. Relaxin added to the bath medium together with l-arginine depressed the amplitude of the spontaneous contractions in the mdx mice to a level similar to that of the normal mice. The nitric oxide synthase (NOS) inhibitor L-N(G)-nitroarginine reverted this effect. In mdx mice pretreated for 18 hours with relaxin, spontaneous motility was greatly reduced in amplitude, resembling that of the normal mice. Concurrently, iNOS expression in the muscle coat was markedly increased. Therefore, in mdx mice, relaxin can restore an ileal motility pattern similar to that of the normal mice by upregulating endogenous NO biosynthesis.
Baccari
Maria Caterina
MC
Department of Physiological Sciences, University of Florence, Florence, Italy.
Calamai
Franco
F
Chiappini
Laura
L
Vannucchi
Maria Giuliana
MG
Bani
Daniele
D
D000818:Animals; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007082:Ileum / Q000187:drug effects* / Q000502:physiology / Q000503:physiopathology; D008297:Male; D051379:Mice; D018101:Mice, Inbred mdx; D009119:Muscle Contraction / Q000187:drug effects*; D020388:Muscular Dystrophy, Duchenne / Q000503:physiopathology*; D009569:Nitric Oxide / Q000378:metabolism; D012065:Relaxin / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects
D009569:Nitric Oxide; D012065:Relaxin