TY - JOUR
T1 - Functional characterization of a muscarinic receptor stimulating gastrin release from rabbit antral G-cell in primary culture
AU - Weigert, Norbert
AU - Schaffer, Kirsten
AU - Wegner, Ute
AU - Schusdziarra, Volker
AU - Classen, Meinhard
AU - Schepp, Wolfgang
N1 - Funding Information:
This study was supported by a grant from the Deutsche Forschungsgemeinschaft (Sche 229/7-1). We wish to thank Prof. G. Lambrecht (Department of Pharmacology, University of Frankfurt, Frankfurt/M, Germany) for valuable discussions and suggestions. The generous help of Prof. Bliimel and collaborators (Department of Experimental Surgery, Technical University of Munich) is gratefully acknowledged.
PY - 1994/11/3
Y1 - 1994/11/3
N2 - In previous studies carbachol-induced stimulation of gastrin release from antral G-cells in primary culture suggested the presence of muscarinic acetylcholine receptors on this cell type. Therefore, we attempted to pharmacologically characterize the muscarinic acetylcholine receptor subtype involved. Enzymatically isolated rabbit antral mucosal cells (0.8% G-cells) were separated by counterflow elutriation yielding a fraction (1.7% G-cells) that was placed in culture on collagen-coated well plates. After 24-36 h of culture 13.0 ± 2.4% of total adherent cells were immunoreactive for gastrin as shown by immunocytochemical staining using the avidin-biotin complex method. In this preparation basal gastrin release ranged from 3.3 ± 0.3 to 4.1 ± 0.3% of total cellular content. Maximal gastrin release in response to the acetylcholine receptor agonist carbachol (10-4 M) or the selective muscarinic receptor agonist arecaidine propargyl ester (10-4 M) was 8.5 ± 0.4% and 7.6 ± 0.4% of total cellular content, respectively. The EC50 values were 3.7 ± 0.5 × 10-6 M carbachol and 1.8 ± 0.4 × 10-6 M arecaidine propargyl ester. At a concentration of 10-6 M the non-selective muscarinic receptor antagonist atropine and the muscarinic M3 receptor preferring antagonist hexahydro-sila-difenidol (HHSiD; M3 ≥ M1 > M2) completely inhibited gastrin release in response to carbachol (Ki values: 52 × 10-9 M atropine and 29 × 10-9 M HHSiD) and arecaidine propargyl ester (Ki values: 11 × 10-9 M atropine and 13 × 10-9 M HHSiD). In contrast the muscarinic M1 receptor preferring antagonist pirenzepine (M1 > M3 ≥ M2) even at high concentrations (10-6-10-5 M) inhibited the carbachol- and arecaidine propargyl ester-induced gastrin release by only about 40%, while the muscarinic M2/M4 receptor antagonist 11-[[4-[4-(diethylamino)butyl]-1-piperidinyl]acetyl]-5,1-dihydro-6H- pyrido[2,3-b][1,4]benzodiazepin-6-one hydrochloride (AQ-RA 741; M2 = M4 > M1 > M3) was ineffective at all concentrations tested (10-9-10-5 M). We conclude that muscarinic receptor agents may directly stimulate gastrin release from antral G-cells via activation of muscarinic M3 receptors most probably residing on the G-cells themselves.
AB - In previous studies carbachol-induced stimulation of gastrin release from antral G-cells in primary culture suggested the presence of muscarinic acetylcholine receptors on this cell type. Therefore, we attempted to pharmacologically characterize the muscarinic acetylcholine receptor subtype involved. Enzymatically isolated rabbit antral mucosal cells (0.8% G-cells) were separated by counterflow elutriation yielding a fraction (1.7% G-cells) that was placed in culture on collagen-coated well plates. After 24-36 h of culture 13.0 ± 2.4% of total adherent cells were immunoreactive for gastrin as shown by immunocytochemical staining using the avidin-biotin complex method. In this preparation basal gastrin release ranged from 3.3 ± 0.3 to 4.1 ± 0.3% of total cellular content. Maximal gastrin release in response to the acetylcholine receptor agonist carbachol (10-4 M) or the selective muscarinic receptor agonist arecaidine propargyl ester (10-4 M) was 8.5 ± 0.4% and 7.6 ± 0.4% of total cellular content, respectively. The EC50 values were 3.7 ± 0.5 × 10-6 M carbachol and 1.8 ± 0.4 × 10-6 M arecaidine propargyl ester. At a concentration of 10-6 M the non-selective muscarinic receptor antagonist atropine and the muscarinic M3 receptor preferring antagonist hexahydro-sila-difenidol (HHSiD; M3 ≥ M1 > M2) completely inhibited gastrin release in response to carbachol (Ki values: 52 × 10-9 M atropine and 29 × 10-9 M HHSiD) and arecaidine propargyl ester (Ki values: 11 × 10-9 M atropine and 13 × 10-9 M HHSiD). In contrast the muscarinic M1 receptor preferring antagonist pirenzepine (M1 > M3 ≥ M2) even at high concentrations (10-6-10-5 M) inhibited the carbachol- and arecaidine propargyl ester-induced gastrin release by only about 40%, while the muscarinic M2/M4 receptor antagonist 11-[[4-[4-(diethylamino)butyl]-1-piperidinyl]acetyl]-5,1-dihydro-6H- pyrido[2,3-b][1,4]benzodiazepin-6-one hydrochloride (AQ-RA 741; M2 = M4 > M1 > M3) was ineffective at all concentrations tested (10-9-10-5 M). We conclude that muscarinic receptor agents may directly stimulate gastrin release from antral G-cells via activation of muscarinic M3 receptors most probably residing on the G-cells themselves.
KW - AQ-RA 741
KW - Antral G-cell
KW - Atropine
KW - Hexahydro-sila-difenidol
KW - Muscarinic M receptor
KW - Muscarinic receptor subtype
KW - Pirenzepine
UR - https://www.scopus.com/pages/publications/0027945878
U2 - 10.1016/0014-2999(94)90671-8
DO - 10.1016/0014-2999(94)90671-8
M3 - Article
C2 - 7698174
AN - SCOPUS:0027945878
SN - 0014-2999
VL - 264
SP - 337
EP - 344
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
IS - 3
ER -