In vivo recording of colonic motility in conscious rats with deficiency of interstitial cells of Cajal, with special reference to the effects of nitric oxide on colonic motility.
BACKGROUND
We recorded in vivo colonic motility in rats with a deficiency of interstitial cells of Cajal (ICC) (Ws/Ws rats) and in wild-type rats (+/+ rats), with special reference to the effects of nitric oxide (NO) on colonic motility in both types of rats, in order to ascertain the role of ICC in colonic motility, and the relationship between NO and ICC in regard to colonic motility.


METHODS
Miniature strain-gauge force transducers were sutured on the surface of the ascending and sigmoid colon of Ws/Ws rats and +/+ rats as controls. After 1 week and a fasting period of 24 h, colonic motility in +/+ and Ws/Ws rats was recorded. We also studied the effect of NO on colonic motility in both types of rats, by means of the administration of N-nitro-L-arginine methyl ester (L-NAME) or L-arginine.


RESULTS
In +/+ rats, there were contractions with high amplitude and long duration in both the ascending and sigmoid colon. The number, amplitude, and duration of contractions in the ascending colon were 9.9/20 min, 6.1 g, and 22.7 s, respectively. These findings in the sigmoid colon were 5.2/20 min, 5.2 g, and 23.0 s, respectively. The number of contractions in the ascending and sigmoid colon in Ws/Ws rats (2.3 and 1.0/20 min) was significantly lower than that in +/+ rats (P < 0.05). The number of contractions in the ascending and sigmoid colon in +/+ rats (9.7 and 5.1/20 min before treatment) was significantly increased by L-NAME administration (28.7 and 13.9/40-60 min after treatment; P < 0.05), but that in Ws/Ws rats was not influenced. The number of contractions in the ascending and sigmoid colon in +/+ rats (10.2 and 5.2/20 min before treatment) was significantly decreased by L-arginine administration (3.6 and 2.1/40-60 min after treatment; P < 0.05), but that in Ws/Ws rats was not influenced.


CONCLUSIONS
ICC must be related to the occurrence of a normal number of colonic contractions. NO may be involved in the inhibitory regulation of colonic motility, and the effect of NO on the occurrence of contractions appears to be mediated by ICC.
Takahashi
Atsushi
A
Department of General Surgical Science (Surgery I), Gunma University, Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi 371-8511, Japan.
Tomomasa
Takeshi
T
Kaneko
Hiroaki
H
Hatori
Reiko
R
Ishige
Takashi
T
Suzuki
Makoto
M
Mochiki
Erito
E
Morikawa
Akihiro
A
Kuwano
Hiroyuki
H
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D044682:Colon, Ascending / Q000166:cytology / Q000502:physiology; D012809:Colon, Sigmoid / Q000166:cytology* / Q000502:physiology*; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D019009:Proto-Oncogene Proteins c-kit; D019331:NG-Nitroarginine Methyl Ester