Scientific Paper Cholinergic receptor induction and JNK activation in acute pancreatitis Isaac Samuel, M.D. a, *, Smita Zaheer, Ph.D. a , Rory A. Fisher, Ph.D. b , Asgar Zaheer, Ph.D. c a Department of Surgery, Veterans Affairs Medical Center, University of Iowa Roy J. and Lucille A. Carver College of Medicine, 200 Hawkins Dr., 4625 JCP, Iowa City, IA 52242, USA b Department of Pharmacology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, USA c Department of Neurology, University of Iowa Roy J. and Lucille A. Carver College of Medicine and the Veterans Affairs Medical Center, Iowa City, IA, USA Manuscript received June 2, 2003; revised manuscript July 16, 2003 Abstract Background: Cholecystokinin-A (CCK-A) and cholinergic receptor pathways, capable of activating stress kinases p38 mitogen-activated protein kinase (p38 MAPK ) and cJUN N-terminal kinase (JNK), are implicated in the pathogenesis of ligation-induced acute pancreatitis in rats. As ligation-induced acute pancreatitis in rats is associated with CCK-A receptor induction and p38 MAPK activation, and as receptor induction could amplify acinar hyperstimulation and exacerbate cell stress, we tested the hypothesis that the cholinergic M3 receptor is induced and JNK is activated in this model. Methods: Cholinergic M3 receptor expression and JNK activation was compared in rats 1, 3, or 24 hours after sham operation or duct ligation. Results: Immunoblot analysis of pancreatic homogenates showed a time-dependent increase in cholinergic M3 receptor protein, total JNK, and phospho-JNK after duct ligation. Conclusions: There is a rapid and progressive cholinergic M3 receptor induction and JNK activation in ligation-induced acute pancreatitis in rats. These findings may have significance in the mechanism of disease pathogenesis. © 2003 Excerpta Medica, Inc. All rights reserved. Keywords: Acute pancreatitis; CCK; Cholinergic receptor; JNK; Stress-activated protein kinase; Signal transduction Acute pancreatitis is a common disease and is potentially fatal [1]. However, as the mechanism of disease pathogen- esis has not yet been elucidated, the initial treatment re- mains merely nonspecific and supportive [1,2]. The rodent model of bile-pancreatic duct ligation-induced acute pan- creatitis is a useful experimental corollary of gallstone- induced acute pancreatitis [2]. Bile-pancreatic duct ligation in rats excludes bile-pan- creatic juice from gut and induces acute pancreatitis [2]. Cholecystokinin-A (CCK-A) and cholinergic receptor-me- diated exocrine pancreatic hyperstimulation secondary to bile-pancreatic juice exclusion is implicated in disease pathogenesis [3]. In dispersed pancreatic acini, stimulation of these G-protein coupled receptors can activate the stress- activated protein kinases p38 mitogen-activated protein ki- nase (p38 MAPK ) and cJUN N-terminal kinase (JNK) [4,5]. We previously showed that duct ligation-induced acute pan- creatitis in rats is associated with CCK-A receptor induction and p38 MAPK activation [6]. In the present study, we show that ligation-induced acute pancreatitis in rats is associated with cholinergic muscarinic (M3) receptor induction and JNK activation. As an increase in the number of G-protein coupled receptors can amplify exclusion-induced exocrine pancreatic hyperstimulation, and as activation of stress ki- nases can induce acinar cell proinflammatory cytokine pro- duction, our observations may have relevance in the mech- anism of disease pathogenesis. Material and methods Material A phospho-MAPK antibody sampler kit (Cat. No. 9910), containing rabbit polyclonal immunoglobulin G (IgG) against phospho-JNK (Thr183/Tyr185; Cat. No. 9251) and * Corresponding author. Tel.: +1-319-384-7220; fax: +1-319-356- 8378. E-mail address: Isaac-samuel@uiowa.edu The American Journal of Surgery 186 (2003) 569 –574 0002-9610/03/$ – see front matter © 2003 Excerpta Medica, Inc. All rights reserved. doi:10.1016/j.amjsurg.2003.07.016