Cholinergic stimulation of pancreatic amylase release and muscarinic receptors: effect of ionophore A23187
Dispersed rat pancreatic acini were incubated in 0.5 mM calcium medium with increasing concentrations of carbamylcholine, with or without the ionophore A23187 (10/sup -6/M). Addition of the ionophore reduced maximal amylase release, increased the maximal effective concentration of carbamylcholine and dramatically impaired the agonist's capacity to induce enzyme secretion at low concentration. The ionophore also abolished the inhibition of secretion observed at high carbamylcholine concentrations. These effects of the ionophore on the cholinergic secretory response cannot be explained by interaction at the muscarinic receptor since neither the Bmax, the affinity of the receptor for the (/sup 3/H)QNB nor the binding of carbamylcholine were affected by the ionophore. It is suggested that for the conditions studied, the ionophore can interact with the secretory process at one or several points ulterior to the initial recognition site of carbamylcholine on its receptor. 30 references, 3 figures.
- Research Organization:
- Universite de Sherbrooke, Quebec
- OSTI ID:
- 5411334
- Journal Information:
- Life Sci.; (United States), Vol. 37:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMYLASE
SECRETION
CHOLINE
BIOLOGICAL EFFECTS
CHEMICAL BONDS
AFFINITY
CALCIUM
DOSE-RESPONSE RELATIONSHIPS
PANCREAS
RATS
RECEPTORS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALCOHOLS
ALKALINE EARTH METALS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
BODY
DIGESTIVE SYSTEM
DRUGS
ELEMENTS
ENDOCRINE GLANDS
ENZYMES
GLANDS
GLYCOSYL HYDROLASES
HYDROLASES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPOTROPIC FACTORS
MAMMALS
METALS
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
ORGANS
QUATERNARY COMPOUNDS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques