Basic Research
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. May 21, 2006; 12(19): 3026-3030
Published online May 21, 2006. doi: 10.3748/wjg.v12.i19.3026
γ-aminobutyric acid secreted from islet β-cells modulates exocrine secretion in rat pancreas
Yong-Deuk Park, Zheng-Yun Cui, Guang Wu, Hyung-Seo Park, Hyoung-Jin Park
Yong-Deuk Park, Department of MedicoLife Science, Youngdong University, Chungbuk, Korea
Zheng-Yun Cui, Guang Wu, Hyoung-Jin Park, Department of Physiology, College of Medicine and Ilsong Institute of Life Science, Hallym University, Chuncheon, Gangwon-do, Korea
Hyung-Seo Park, Department of Physiology, College of Medicine, Konyang University, Daejeon, Korea
Author contributions: All authors contributed equally to the work
Supported by the Hallym Academy of Sciences, Hallym University, Korea in 2001 (to HJ Park)
Correspondence to: Hyoung-Jin Park, MD, PhD, Department of Physiology, College of Medicine, Hallym University, 1 Okchon-Dong, Chuncheon, Gangwon-Do, 200-702, Republic of Korea. hjpark@hallym.ac.kr
Telephone: +82-33-2482582 Fax: +82-33-2551640
Received: December 5, 2005
Revised: January 10, 2006
Accepted: January 19, 2006
Published online: May 21, 2006
Abstract

AIM: To investigate the role of endogenous γ-amino-butyric acid (GABA) in pancreatic exocrine secretion.

METHODS: The isolated, vascularly perfused rat pancreas was employed in this study to eliminate the possible influences of extrinsic nerves and hormones. Cholecystokinin (CCK; 10 pmol/L) was intra-arterially given to stimulate exocrine secretion of the pancreas.

RESULTS: Glutamine, a major precursor of GABA, which was given intra-arterially at concentrations of 1, 4 and 10 mmol/L, dose-dependently elevated the CCK-stimulated secretions of fluid and amylase in the normal pancreas. Bicuculline (10 μmol/L), a GABAA receptor antagonist, blocked the enhancing effect of glutamine (4 mmol/L) on the CCK-stimulated exocrine secretions. Glutamine, at concentrations of 1, 4 and 10 mmol/L, dose-dependently increased the GABA concentration in portal effluent of the normal pancreas. The effects of glutamine on the CCK-stimulated exocrine secretion as well as the GABA secretion were markedly reduced in the streptozotocin-treated pancreas.

CONCLUSION: GABA could be secreted from β-cells into the islet-acinar portal system after administration of glutainine, and could enhance the CCK-stimulated exocrine secretion through GABAA receptors. Thus, GABA in islet β-cells is a hormone modulating pancreatic exocrine secretion.

Keywords: GABA; GABAA receptor; GABA secretion; Cholecystokinin; Islet of langerhans; Pancreas