BIOMAT Database Logo BIOMAT Database Logo

Pertussis toxin-sensitive pathway inhibits glucose-stimulated Ca2+ signals of rat islet beta-cells by affecting L-type Ca2+ channels and voltage-dependent K+ channels. 2004

Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Department of Physiology, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan.

A role of pertussis toxin (PTX)-sensitive pathway in regulation of glucose-stimulated Ca2+ signaling in rat islet beta-cells was investigated by using clonidine as a selective agonist to alpha2-adrenoceptors which link to the pathway. An elevation of extracellular glucose concentration from 5.5 to 22.2 mM (glucose stimulation) increased the levels of [Ca2+]i of beta-cells, and clonidine reversibly reduced the elevated levels of [Ca2+]i. This clonidine effect was antagonized by yohimbine, and abolished in beta-cells pre-treated with PTX. Clonidine showed little effect on membrane currents including those through ATP-sensitive K+ channels induced by voltage ramps from -90 to -50 mV. Clonidine showed little effect on the magnitude of whole-cell currents through L-type Ca2+ channels (ICa(L)), but increased the inactivation process of the currents. Clonidine increased the magnitude of the voltage-dependent K+ currents (IVK). These clonidine effects on ICa(L) and IVK were abolished in beta-cells treated with PTX or GDP-betaS. These results suggest that the PTX-sensitive pathway increases IVK activity and decreases ICa(L) activity of islet beta-cells, resulting in a decrease in the levels of [Ca2+]i elevated by depolarization-induced Ca2+ entry. This mechanism seems responsible at least in part for well-known inhibitory action of PTX-sensitive pathway on glucose-stimulated insulin secretion from islet beta-cells.

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
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
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
D003000 Clonidine An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION. Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
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
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
D017208 Rats, Wistar A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain. Wistar Rat,Rat, Wistar,Wistar Rats
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

Related Publications

Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Intracellular cAMP potentiates voltage-dependent activation of L-type Ca2+ channels in rat islet beta-cells.
March 1998, Pflugers Archiv : European journal of physiology,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
VIP inhibits N-type Ca2+ channels of sympathetic neurons via a pertussis toxin-insensitive but cholera toxin-sensitive pathway.
September 1994, Neuron,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Raloxifene relaxes rat cerebral arteries in vitro and inhibits L-type voltage-sensitive Ca2+ channels.
July 2004, Stroke,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Alpha-latrotoxin induces exocytosis by inhibition of voltage-dependent K+ channels and by stimulation of L-type Ca2+ channels via latrophilin in beta-cells.
March 2006, The Journal of biological chemistry,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Pertussis toxin-sensitive G-proteins: participation in the modulation of voltage-dependent Ca2+ channels by hormones and neurotransmitters.
January 1990, Advances in second messenger and phosphoprotein research,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Role of pertussis toxin-sensitive G-protein, K+ channels, and voltage-gated Ca2+ channels in the antinociceptive effect of inosine.
March 2013, Purinergic signalling,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Role of voltage-dependent Na+ channels for rhythmic Ca2+ signalling in glucose-stimulated mouse pancreatic beta-cells.
May 1999, Cellular signalling,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Chick RGS2L demonstrates concentration-dependent selectivity for pertussis toxin-sensitive and -insensitive pathways that inhibit L-type Ca2+ channels.
May 2003, The Journal of physiology,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
Coassembly of big conductance Ca2+-activated K+ channels and L-type voltage-gated Ca2+ channels in rat brain.
August 2004, The Journal of biological chemistry,
Sechiko Suga, and Teruko Takeo, and Kyoko Nakano, and Tatsusuke Sato, and Takanori Igarashi, and Daisuke Yamana, and Makoto Wakui
The beta 1 subunit of L-type voltage-gated Ca2+ channels independently binds to and inhibits the gating of large-conductance Ca2+-activated K+ channels.
February 2008, Molecular pharmacology,
Copied contents to your clipboard!