Microinjection of TRH analogs into the raphe pallidus stimulates gastric acid secretion in the rat.

Abstract

The effects of microinjection of the stable thyrotropin-releasing hormone (TRH) analog, RX 77368, [pGlu-His-(3,3'-dimethyl)-Pro-NH2] into the raphe pallidus on gastric acid secretion were studied in urethane-anesthetized rats with gastric fistula. RX 77368 microinjected into the raphe pallidus at doses of 0.07, 0.7 and 7.7 pmol induced a dose-dependent net stimulation of gastric acid secretion (7 +/- 4, 50 +/- 7 and 61 +/- 12 mumol/h respectively). The peak acid response was reached within 30 min and returned to basal level 90 min post-injection. The stimulatory effect was abolished by bilateral cervical vagotomy and pirenzepine pretreatment (1 mg/kg, i.v.). RX 77368 (7.7 pmol) microinjected into the inferior olive or pyramidal tract induced smaller or no gastric acid secretory response. These results demonstrate that chemical stimulation of the raphe pallidus increases gastric acid secretion through vagal pathways and peripheral muscarinic receptors. These data suggest that the nucleus raphe pallidus may be involved in vagal modulation of gastric acid secretion in the rat.

• Authors: H Yang, T Ishikawa, Y Taché
• Journal: Brain research (Brain Res) Vol. 531 Issue 1-2 Pg. 280-5 (Oct 29 1990) ISSN: 0006-8993 [Print] Netherlands
• PMID: 2126972 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Thyrotropin-Releasing Hormone
• L-pyroglutamyl-L-histidyl-3,3-dimethylprolinamide
• Pyrrolidonecarboxylic Acid

Topics

• Animals
• Dose-Response Relationship, Drug
• Gastric Acid (metabolism)
• Gastric Juice (drug effects)
• Kinetics
• Male
• Medulla Oblongata (drug effects, physiology)
• Microinjections
• Pyrrolidonecarboxylic Acid (analogs & derivatives)
• Raphe Nuclei (drug effects, physiology)
• Rats
• Rats, Inbred Strains
• Reference Values
• Thyrotropin-Releasing Hormone (administration & dosage, analogs & derivatives, pharmacology)