Involvement of capsaicin-sensitive sensory nerves in gastric adaptive relaxation in isolated guinea-pig stomachs.
We investigated the role of capsaicin-sensitive sensory nerves (CPSNs), nitric oxide (NO), calcitonin gene-related peptide (CGRP) and vasoactive intestinal peptide (VIP) in gastric adaptive and receptive relaxation in isolated guineapig stomachs. Changes in intragastric volume and pressure were recorded simultaneously in isolated stomachs in baths containing atropine and guanethidine. Adaptive relaxation was induced by luminal distention, and receptive relaxation was induced by electrical vagal stimulation. We found that desensitization to capsaicin inhibited adaptive relaxation, but not vagally induced relaxation. Extraluminal capsaicin induced gastric relaxation. Adaptive relaxation and capsaicin-induced relaxation were reduced by both tetrodotoxin and NG-nitro-L-arginine (LNNA), but not by hexamethonium. The effect of LNNA was partially reversed by co-incubation with L-arginine. Neither CGRP(8-37) nor VIP(10-28) inhibited all responses of adaptive relaxation, vagally induced and capsaicin-induced relaxation. These findings suggest that activation of CPSNs may be involved in adaptive relaxation, and that NO, but not CGRP or VIP, may be involved in the mechanisms of adaptive relaxation and receptive relaxation.
Uno
H
H
Third Department of Internal Medicine, Osaka City University Medical School, Japan.
Arakawa
T
T
Fukuda
T
T
Higuchi
K
K
Kobayashi
K
K
D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology / Q000502:physiology; D002211:Capsaicin / Q000494:pharmacology*; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005730:Ganglionic Blockers / Q000494:pharmacology; D005753:Gastric Mucosa / Q000502:physiology*; D006168:Guinea Pigs; D018738:Hexamethonium / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008916:Miotics / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D019335:Nitroarginine / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D013270:Stomach / Q000187:drug effects / Q000294:innervation*; D013779:Tetrodotoxin / Q000494:pharmacology; D014630:Vagus Nerve / Q000187:drug effects*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology / Q000502:physiology
D004791:Enzyme Inhibitors; D005730:Ganglionic Blockers; D008916:Miotics; D010446:Peptide Fragments; C058636:calcitonin gene-related peptide (8-37); D019335:Nitroarginine; D009569:Nitric Oxide; D014660:Vasoactive Intestinal Peptide; D018738:Hexamethonium; D013779:Tetrodotoxin; C047945:vasoactive intestinal peptide (10-28); D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin