Acid-sensitive and alkaline-sensitive sensory neurons regulate pH dependent gastrin secretion in rat.
We examined the role of capsaicin-sensitive afferent neurons in pH-dependent gastrin secretion in the rat stomach. The change in serum gastrin levels relative to changes in luminal pH (using omeprazole for luminal alkalization or 0.1 N HCl for luminal acidification) was studied after oral administration of 4% lidocaine or capsaicin-induced ablation of afferent neurons. The increase of serum gastrin levels by luminal alkalization was significantly inhibited (50%) after administration of 4% lidocaine. Capsaicin pretreatment (125 mg/kg subcutaneously over two days) inhibited the change in serum gastrin levels both the luminal alkalization (38%) and acidification (66%). Antral gastrin contents, somatostatin contents, gastrin mRNA expression, and somatostatin mRNA expression were not significantly affected by capsaicin pretreatment. Our results indicate that capsaicin-sensitive afferent neurons participate in the secretion of gastrin by luminal alkalization and inhibition of gastrin by luminal acidification.
Nojima
K
K
First Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
Sumii
K
K
Sumii
M
M
Okahara
S
S
Haruma
K
K
Yoshihara
M
M
Kajiyama
G
G
D000143:Acids / Q000494:pharmacology*; D000468:Alkalies / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D005755:Gastrins / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology*; D011706:Pyloric Antrum / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013004:Somatostatin / Q000235:genetics / Q000378:metabolism
D000143:Acids; D000468:Alkalies; D000779:Anesthetics, Local; D005755:Gastrins; D012333:RNA, Messenger; D013004:Somatostatin; D006859:Hydrogen; D008012:Lidocaine; D002211:Capsaicin