Intracisternal TRH analog increases gastrin release and corpus histidine decarboxylase activity in rats.
Thyrotropin-releasing hormone (TRH) acts in brain stem nuclei to induce vagally mediated stimulation of gastric secretion. The effects of intracisternal injection of the TRH analog RX-77368 on plasma gastrin levels and corpus histidine decarboxylase (HDC) activity were studied in 48-h fasted conscious rats. RX-77368 (25-100 ng) increased plasma gastrin levels by threefold at 30 min, which remained significantly higher than control at 2 and 4 h postinjection. Corpus HDC activity began to increase at 2 h and reached a peak at 4 h postinjection with a 21-fold maximum response observed at 50 ng. Morphological changes in the appearance of corpus HDC-immunoreactive cells correlated well with HDC activity. Pretreatment with gastrin monoclonal antibody completely prevented RX-77368 stimulatory effects on HDC activity. Atropine significantly attenuated gastrin increase at 30 min by 26%. These results indicated that in conscious fasted rats, TRH analog acts in the brain to increase corpus HDC activity in the enterochromaffin-like cells, which involves gastrin release stimulated by central TRH analog.
Song
M
M
CURE: Digestive Diseases Research Center, West Los Angeles Veterans Affairs Medical Center, Los Angeles, California 90073, USA.
Yang
H
H
Walsh
J H
JH
Ohning
G
G
Wong
H
H
Taché
Y
Y
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000235:genetics*; D005753:Gastric Mucosa / Q000201:enzymology*; D005755:Gastrins / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D006640:Histidine Decarboxylase / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008845:Microinjections; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D051381:Rats; D017207:Rats, Sprague-Dawley; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors
D000911:Antibodies, Monoclonal; D005755:Gastrins; D013973:Thyrotropin-Releasing Hormone; C027979:L-pyroglutamyl-L-histidyl-3,3-dimethylprolinamide; D001285:Atropine; D019204:GTP-Binding Proteins; D006640:Histidine Decarboxylase; D011761:Pyrrolidonecarboxylic Acid