Decrease in participation of nitric oxide in nonadrenergic, noncholinergic relaxation of rat intestine with age.
Participation of nitric oxide in the electrical field stimulation-induced nonadrenergic, noncholinergic (NANC) relaxation in various intestinal regions was studied in 2- to 50-week-old Wistar rats. In the jejunum of 2-week-old rats, the extent of the nitric oxide-mediated component of the relaxation of longitudinal muscle was approximately 60-70%, whereas the component was 40-50% in 4-week-old rats and was absent in 8- and 50-week-old rats. Thus, nitric oxide seems to be the most important mediator at young ages but its significance is lost with age. The same tendency as that in the jejunum was also shown in longitudinal muscle of the ileum, proximal and distal colon, and rectum. The tendency was also shown in the circular muscle of the rectum. Sensitivity of the longitudinal muscle of the jejunum and proximal colon to exogenously added nitric oxide was high in younger rats. Immunoreactive structures for nitric oxide synthase were observed in the circular muscle layer of the rectum. The population of the structures was denser in 4-week-old than that in 50-week-old. The results suggest that NANC relaxation in every region of the intestine at 2-week-old is almost solely mediated by nitric oxide, and its significance as an inhibitory mediator gradually or rapidly decreases with age.
Takeuchi
T
T
Department of Veterinary Pharmacology, College of Agriculture, Research Institute for Advanced Science and Technology, Osaka Prefecture University, Sakai, Japan.
Niioka
S
S
Yamaji
M
M
Okishio
Y
Y
Ishii
T
T
Nishio
H
H
Takatsuji
K
K
Hata
F
F
D018663:Adrenergic Agents / Q000494:pharmacology; D000375:Aging / Q000502:physiology*; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D003106:Colon / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006145:Guanethidine / Q000494:pharmacology; D006801:Humans; D007082:Ileum / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007231:Infant, Newborn; D007422:Intestines / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D007583:Jejunum / Q000187:drug effects / Q000502:physiology; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D009197:Myenteric Plexus / Q000201:enzymology; D009569:Nitric Oxide / Q000494:pharmacology / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I; D019335:Nitroarginine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012007:Rectum / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D013997:Time Factors
D018663:Adrenergic Agents; D004791:Enzyme Inhibitors; D018727:Muscarinic Antagonists; D019335:Nitroarginine; D009569:Nitric Oxide; D001285:Atropine; D001120:Arginine; C496320:NOS1 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat; D006145:Guanethidine