Different modulation of spontaneous activities by nitrergic inhibitory nerves between ileum and jejunum in W/Wv mutant mice.
We compared the spontaneous electrical and mechanical activities between the jejunum and ileum in the W/Wv mutant mouse, where ICC in the myenteric region (ICC-MY) are deficient. Electrical slow waves (SWs) superimposed with spike potentials, and synchronous circular and longitudinal muscle mechanical activities at a regular rhythm under approximately 1 cm H2O were recorded in the jejunum and ileum of wild-type mice. However, in the jejunum and ileum of W/Wv mice, irregular electrical and mechanical activities without discernable SWs were recorded. N-nitro-L-arginine methyl ester (L-NAME) significantly decreased the mean interval of longitudinal muscle contractions from 4.43+/-3.39 to 2.50+/-1.23 s in the ileum of W/W(V) mice. L-NAME also significantly decreased mean coefficient of variance (decreased irregularity) in the intervals from 2.59+/-0.84 to 0.48+/-0.46 in the ileum. Tetrodotoxin also significantly decreased mean interval and coefficient of variance in the ileum. Neither L-NAME nor tetrodotoxin affected contractile activity in the jejunum. These results suggest that enteric nitrergic nerves in the ileum, but not the jejunum, mediate a steady-state inhibition of myogenic activity in W/Wv mice.
Nakagawa
Tadashi
T
Department of Physiology II, Nara Medical University School of Medicine, 840 Shijo-cho, Kashihara, Nara 634-8521, Japan.
Ueshima
Shigeyuki
S
Fujii
Hisao
H
Nakajima
Yoshiyuki
Y
Takaki
Miyako
M
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D007082:Ileum / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007583:Jejunum / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D026602:Nitrergic Neurons / Q000187:drug effects / Q000502:physiology*
D019331:NG-Nitroarginine Methyl Ester