Biomaterial Database

Intracellular cAMP potentiates voltage-dependent activation of L-type Ca2+ channels in rat islet beta-cells. 1998

T Kanno, and S Suga, and J Wu, and M Kimura, and M Wakui

Department of Physiology, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki 036, Japan.

Intracellular cAMP-dependent modulation of L-type Ca2+ channel activation in cultured rat islet beta-cells has been investigated using the patch-clamp whole-cell current recording mode. The L-type voltage-dependent Ca2+ current (ICa) showed a fast activation followed by a slow inactivation, and was sensitive to Ca2+ channel blockers, for example nifedipine. Application of a cAMP analogue, dibutyryl cyclic AMP (db-cAMP), increased the magnitude of the peak ICa in a concentration-dependent manner. Values of the half-activation potentials (V1/2), taken from activation curves for ICa, were -16.7 +/- 1.8 and -21.9 +/- 3.4 mV (P < 0.05) before and after application of db-cAMP, respectively, with no change of the slope factor (k) or the reversal potential. Pretreatment with a specific protein kinase A antagonist, Rp-cAMP, prevented the potentiating effect of db-cAMP. These results indicate that in rat islet beta-cells, phosphorylation of cAMP-dependent kinase potentiates the voltage-dependent activation of L-type Ca2+ channels.

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
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
D003994	Bucladesine	A cyclic nucleotide derivative that mimics the action of endogenous CYCLIC AMP and is capable of permeating the cell membrane. It has vasodilator properties and is used as a cardiac stimulant. (From Merck Index, 11th ed)	Dibutyryl Adenosine-3',5'-Monophosphate,Dibutyryl Cyclic AMP,(But)(2) cAMP,Bucladesine, Barium (1:1) Salt,Bucladesine, Disodium Salt,Bucladesine, Monosodium Salt,Bucladesine, Sodium Salt,DBcAMP,Dibutyryl Adenosine 3,5 Monophosphate,N',O'-Dibutyryl-cAMP,N(6),0(2')-Dibutyryl Cyclic AMP,AMP, Dibutyryl Cyclic,Adenosine-3',5'-Monophosphate, Dibutyryl,Cyclic AMP, Dibutyryl,Dibutyryl Adenosine 3',5' Monophosphate,Disodium Salt Bucladesine,Monosodium Salt Bucladesine,N',O' Dibutyryl cAMP,Sodium Salt Bucladesine
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
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
D013779	Tetrodotoxin	An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.	Fugu Toxin,Tarichatoxin,Tetradotoxin,Toxin, Fugu
D015220	Calcium Channels	Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.	Ion Channels, Calcium,Receptors, Calcium Channel Blocker,Voltage-Dependent Calcium Channel,Calcium Channel,Calcium Channel Antagonist Receptor,Calcium Channel Antagonist Receptors,Calcium Channel Blocker Receptor,Calcium Channel Blocker Receptors,Ion Channel, Calcium,Receptors, Calcium Channel Antagonist,VDCC,Voltage-Dependent Calcium Channels,Calcium Channel, Voltage-Dependent,Calcium Channels, Voltage-Dependent,Calcium Ion Channel,Calcium Ion Channels,Channel, Voltage-Dependent Calcium,Channels, Voltage-Dependent Calcium,Voltage Dependent Calcium Channel,Voltage Dependent Calcium Channels
D015640	Ion Channel Gating	The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.	Gating, Ion Channel,Gatings, Ion Channel,Ion Channel Gatings