Biomaterial Database

Pre- and postjunctional muscarinic receptors in canine bronchi. 1990

L J Janssen, and E E Daniel

Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.

Cholinergic receptors on canine bronchial smooth muscle (mediating excitation) or on the cholinergic nerve endings (modulating acetylcholine release) have not yet been characterized. In this study, the effects of agents selective for the various muscarinic receptors on mechanical and electrical responses in isolated segments of canine bronchial smooth muscle (3rd-6th order) were investigated. Carbachol (Cch), bethanechol (Bch), oxotremorine (Oxo), and McNeil A343 (McN) produced membrane depolarization and contractions with a ranked potency order of Oxo approximately Cch greater than Bch greater than McN. Oxo-induced contractions were antagonized by pirenzepine (Pir), AF-DX 116 (AF-DX), or hexahydrosiladifenidol (Hexa); Schild analysis yielded pA2 values of 6.61, 6.81, and 7.40, respectively. Contractions induced by field stimulation (FS) were antagonized by Pir, AF-DX, or Hexa with a potency order of Hexa greater than AF-DX approximately Pir. FS responses were potentiated by lower (i.e., M1-selective) concentrations of Pir, and antagonized by McN. The non-M1 agonists and antagonists had no such effects. These findings indicate that the postjunctional receptors are of the M3 subtype, and that the inhibitory receptors on the cholinergic nerve endings are of the M1 subtype.

UI	MeSH Term	Description	Entries
D008455	(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride	A drug that selectively activates certain subclasses of muscarinic receptors and also activates postganglionic nicotinic receptors. It is commonly used experimentally to distinguish muscarinic receptor subtypes.	McN A-343,McN-A-343,McN-A343,McNeil A 343,A 343, McNeil,McN A 343,McN A343,McNA343
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D008839	Microelectrodes	Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)	Electrodes, Miniaturized,Electrode, Miniaturized,Microelectrode,Miniaturized Electrode,Miniaturized Electrodes
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D010095	Oxotremorine	A non-hydrolyzed muscarinic agonist used as a research tool.	Oxytremorine
D010880	Piperidines	A family of hexahydropyridines.
D010890	Pirenzepine	An antimuscarinic agent that inhibits gastric secretion at lower doses than are required to affect gastrointestinal motility, salivary, central nervous system, cardiovascular, ocular, and urinary function. It promotes the healing of duodenal ulcers and due to its cytoprotective action is beneficial in the prevention of duodenal ulcer recurrence. It also potentiates the effect of other antiulcer agents such as CIMETIDINE and RANITIDINE. It is generally well tolerated by patients.	Gastrotsepin,Gastrozepin,L-S 519,LS-519,Piren-Basan,Pirenzepin,Pirenzepin Von Ct,Pirenzepin-Ratiopharm,Pirenzepine Dihydrochloride,Pyrenzepine,Ulcoprotect,Ulgescum,Dihydrochloride, Pirenzepine,LS 519,LS519,Piren Basan,Pirenzepin Ratiopharm,Von Ct, Pirenzepin
D011976	Receptors, Muscarinic	One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.	Muscarinic Acetylcholine Receptors,Muscarinic Receptors,Muscarinic Acetylcholine Receptor,Muscarinic Receptor,Acetylcholine Receptor, Muscarinic,Acetylcholine Receptors, Muscarinic,Receptor, Muscarinic,Receptor, Muscarinic Acetylcholine,Receptors, Muscarinic Acetylcholine
D001980	Bronchi	The larger air passages of the lungs arising from the terminal bifurcation of the TRACHEA. They include the largest two primary bronchi which branch out into secondary bronchi, and tertiary bronchi which extend into BRONCHIOLES and PULMONARY ALVEOLI.	Primary Bronchi,Primary Bronchus,Secondary Bronchi,Secondary Bronchus,Tertiary Bronchi,Tertiary Bronchus,Bronchi, Primary,Bronchi, Secondary,Bronchi, Tertiary,Bronchus,Bronchus, Primary,Bronchus, Secondary,Bronchus, Tertiary