Biomaterial Database

Quinine blocks the high conductance, calcium-activated potassium channel in rat pancreatic beta-cells. 1990

E Mancilla, and E Rojas

Laboratory of Cell Biology and Genetics, NIDDK, National Institutes of Health, Bethesda, MD 20892.

The [Ca2+]i-activated K+-channel, one of the 3 K+ -channels described in pancreatic beta-cells, is a high conductance, voltage-dependent K+-channel. Quinine, known to block [Ca2+]i-activated K(+)-channels in other cells, has been described to block the silent phase between the bursts of glucose-evoked electrical activity in mouse pancreatic beta-cells, and to inhibit K+ efflux from rat pancreatic islets. We report here that quinine blocks the [Ca2+]i-activated K(+)-channel in rat pancreatic beta-cells from the external side of the membrane. We also show that the blockade is characterized by fast flickering of the K(+)-channel between the open and closed state. Mean open and closed times within bursts were found to be exponentially distributed, suggesting that the blockade by quinine involves obstruction on the K(+) flow through the open to be exponentially distributed, suggesting that the blockade by quinine involves obstruction on the K+ flow through the open channel.

UI	MeSH Term	Description	Entries
D007515	Islets of Langerhans	Irregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the PANCREAS among the exocrine acini. Each islet is surrounded by connective tissue fibers and penetrated by a network of capillaries. There are four major cell types. The most abundant beta cells (50-80%) secrete INSULIN. Alpha cells (5-20%) secrete GLUCAGON. PP cells (10-35%) secrete PANCREATIC POLYPEPTIDE. Delta cells (~5%) secrete SOMATOSTATIN.	Islands of Langerhans,Islet Cells,Nesidioblasts,Pancreas, Endocrine,Pancreatic Islets,Cell, Islet,Cells, Islet,Endocrine Pancreas,Islet Cell,Islet, Pancreatic,Islets, Pancreatic,Langerhans Islands,Langerhans Islets,Nesidioblast,Pancreatic Islet
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011803	Quinine	An alkaloid derived from the bark of the cinchona tree. It is used as an antimalarial drug, and is the active ingredient in extracts of the cinchona that have been used for that purpose since before 1633. Quinine is also a mild antipyretic and analgesic and has been used in common cold preparations for that purpose. It was used commonly and as a bitter and flavoring agent, and is still useful for the treatment of babesiosis. Quinine is also useful in some muscular disorders, especially nocturnal leg cramps and myotonia congenita, because of its direct effects on muscle membrane and sodium channels. The mechanisms of its antimalarial effects are not well understood.	Biquinate,Legatrim,Myoquin,Quinamm,Quinbisan,Quinbisul,Quindan,Quinimax,Quinine Bisulfate,Quinine Hydrochloride,Quinine Lafran,Quinine Sulfate,Quinine Sulphate,Quinine-Odan,Quinoctal,Quinson,Quinsul,Strema,Surquina,Bisulfate, Quinine,Hydrochloride, Quinine,Sulfate, Quinine,Sulphate, Quinine
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002463	Cell Membrane Permeability	A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.	Permeability, Cell Membrane
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D005947	Glucose	A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.	Dextrose,Anhydrous Dextrose,D-Glucose,Glucose Monohydrate,Glucose, (DL)-Isomer,Glucose, (alpha-D)-Isomer,Glucose, (beta-D)-Isomer,D Glucose,Dextrose, Anhydrous,Monohydrate, Glucose
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