Muscarinic receptor subtypes mediating the mucosal response to neural stimulation of guinea pig ileum
Muscarinic receptors involved in the secretory response evoked by electrical stimulation of submucosal neutrons were investigated in muscle-stripped flat sheets of guinea pig ileum set up in flux chambers. Neural stimulation produced a biphasic increase in short-circuit current due to active chloride secretion. Atropine and 4-diphenylacetoxy-N-methylpiperadine methiodide (4-DAMP) (10/sup -7/ M) were more potent inhibitors of the cholinergic phase of the response than was pirenzepine. Dose-dependent increases in base-line short-circuit current were evoked by carbachol and bethanechol; 4-hydroxy-2-butynyl trimethylammonium chloride (McN A343) produced a much smaller effect. Tetrodotoxin abolished the effects of McN A343 but did not alter the responses of carbachol and bethanechol. McN A343 significantly reduced the cholinergic phase of the neurally evoked response and caused a rightward shift of the carbachol dose-response curve. All muscarinic compounds inhibited (/sup 3/H)quinuclidinyl benzilate binding to membranes from muscosal scrapings, with a rank order of potency of 4-DAMP > pirenzepine > McN A343 > carbachol > bethanechol. These results suggest that acetylcholine released from submucosal neurons mediates chloride secretion by interacting with muscarinic cholinergic receptors that display a high binding affinity for 4-DAMP. Activation of neural muscarinic receptors makes a relatively small contribution to the overall secretory response.
- Research Organization:
- Ohio State Univ., Columbus (USA)
- OSTI ID:
- 6803254
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 253:3
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ELECTRIC FIELDS
BIOLOGICAL EFFECTS
IONS
SECRETION
RECEPTORS
BIOCHEMICAL REACTION KINETICS
CHEMICAL ACTIVATION
SYMPATHOMIMETICS
RADIORECEPTOR ASSAY
ALCOHOLS
ATROPINE
CHLORIDES
DOSE-RESPONSE RELATIONSHIPS
GUINEA PIGS
MEMBRANE TRANSPORT
MUCOUS MEMBRANES
NERVE CELLS
SMALL INTESTINE
TOXINS
TRITIUM COMPOUNDS
ALKALOIDS
ANIMAL CELLS
ANIMALS
ANTIGENS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CHARGED PARTICLES
CHLORINE COMPOUNDS
DIGESTIVE SYSTEM
DRUGS
GASTROINTESTINAL TRACT
HALIDES
HALOGEN COMPOUNDS
HYDROXY COMPOUNDS
INTESTINES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
ORGANIC COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PROTEINS
REACTION KINETICS
RODENTS
SOMATIC CELLS
TOXIC MATERIALS
TRACER TECHNIQUES
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
560400 - Other Environmental Pollutant Effects