Biomaterial Database

Membrane mechanism associated with muscarinic receptor activation in single cells freshly dispersed from the rat anococcygeus muscle. 1987

N G Byrne, and W A Large

Department of Pharmacology and Clinical Pharmacology, St George's Hospital Medical School, London.

1 The mechanism of action of carbachol was studied on freshly dispersed cells of the rat anococcygeus using microelectrodes and patch pipettes. 2 Micro-ionophoretic application of carbachol evoked reproducible depolarizations which were reduced or blocked by atropine (10(-7)-10(-6) M). The time courses of the responses to noradrenaline and carbachol were similar. 3 The reversal potential of the carbachol-induced response was -3.8 mV and similar to the value (-6.2 mV) found for noradrenaline. 4 During the response to carbachol the membrane conductance was increased. At depolarized membrane potentials carbachol evoked biphasic membrane responses suggesting an increase in two separate ionic conductances. 5 With patch pipettes in the whole-cell configuration under voltage-clamp, carbachol produced an inward current at a holding potential of -50 mV. The inward current was associated with an increase in membrane conductance with an equilibrium potential of about 0 mV. 6 It is suggested that muscarinic receptors and adrenoceptors in the rat anococcygeus may activate similar membrane conductances. The most prominent mechanism is an increase in chloride ion conductance.

UI	MeSH Term	Description	Entries
D008297	Male		Males
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
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
D009638	Norepinephrine	Precursor of epinephrine that is secreted by the ADRENAL MEDULLA and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the LOCUS CERULEUS. It is also found in plants and is used pharmacologically as a sympathomimetic.	Levarterenol,Levonorepinephrine,Noradrenaline,Arterenol,Levonor,Levophed,Levophed Bitartrate,Noradrenaline Bitartrate,Noradrénaline tartrate renaudin,Norepinephrin d-Tartrate (1:1),Norepinephrine Bitartrate,Norepinephrine Hydrochloride,Norepinephrine Hydrochloride, (+)-Isomer,Norepinephrine Hydrochloride, (+,-)-Isomer,Norepinephrine d-Tartrate (1:1),Norepinephrine l-Tartrate (1:1),Norepinephrine l-Tartrate (1:1), (+,-)-Isomer,Norepinephrine l-Tartrate (1:1), Monohydrate,Norepinephrine l-Tartrate (1:1), Monohydrate, (+)-Isomer,Norepinephrine l-Tartrate (1:2),Norepinephrine l-Tartrate, (+)-Isomer,Norepinephrine, (+)-Isomer,Norepinephrine, (+,-)-Isomer
D010646	Phentolamine	A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.	Fentolamin,Phentolamine Mesilate,Phentolamine Mesylate,Phentolamine Methanesulfonate,Phentolamine Mono-hydrochloride,Regitine,Regityn,Rogitine,Z-Max,Mesilate, Phentolamine,Mesylate, Phentolamine,Methanesulfonate, Phentolamine,Mono-hydrochloride, Phentolamine,Phentolamine Mono hydrochloride
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
D002217	Carbachol	A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.	Carbamylcholine,Carbacholine,Carbamann,Carbamoylcholine,Carbastat,Carbocholine,Carboptic,Doryl,Isopto Carbachol,Jestryl,Miostat,Carbachol, Isopto
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia