Spontaneous mechanical activity and evoked responses in isolated gastric preparations from normal and dystrophic (mdx) mice.
This study examined whether alterations of the spontaneous and evoked mechanical activity are present in the stomach of the mdx mouse, the animal model for Duchenne muscular dystrophy. The gastric mechanical activity from whole-organ of normal and mdx mice was recorded in vitro as changes of intraluminal pressure. All gastric preparations developed spontaneous tone and phasic contractions, although the tone of the mdx preparations was significantly greater. Atropine reduced the tone of the two preparations by the same degree. Nomega-nitro-l-arginine methyl ester (l-NAME) significantly increased the tone and spontaneous contractions only in the stomach from normal animals, but did not affect on the mdx preparations. Effects ofl-NAME on tone and contractility were preserved in the presence of tetrodotoxin. In both types of tissues electrical field stimulation (EFS) induced a biphasic response: cholinergic contraction followed by slow relaxation. In nonadrenergic noncholinergic conditions, EFS induced a rapid relaxation followed by a slow component in both types of tissues. l-NAME abolished the rapid component, reduced the slow component and unmasked tachychinergic contractions. No significant difference was found in evoked responses. The enteric neurotransmission is preserved in mdx gastric preparations, although alterations in the ongoing production of nitric oxide are present.
Mulè
F
F
Dipartimento di Biologia cellulare e dello Sviluppo, Università di Palermo, Italia. fmule@unipa.it
Serio
R
R
D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D051379:Mice; D018101:Mice, Inbred mdx; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D009137:Muscular Dystrophy, Animal / Q000503:physiopathology*; D020388:Muscular Dystrophy, Duchenne / Q000503:physiopathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D009924:Organ Culture Techniques; D013270:Stomach / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
D000779:Anesthetics, Local; D018679:Cholinergic Agonists; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D009599:Nitroprusside; D009569:Nitric Oxide; D013779:Tetrodotoxin; D002217:Carbachol; D019331:NG-Nitroarginine Methyl Ester