Biomaterial Database

Nucleotide Regulation of a calcium-activated cation channel in the rat insulinoma cell line, CRI-G1. 1994

V Reale, and C N Hales, and M L Ashford

Department of Clinical Biochemistry, University of Cambridge, New Addenbrookes Hospital, United Kingdom.

The nucleotide regulation of a calcium-activated nonselective cation (Ca-NS+) channel has been investigated in the rat insulinoma cell line CRI-G1. The activity of the channel is reduced by both AMP and ADP (1-100 microM) in a concentration-dependent manner, with AMP being more potent than ADP. At lower concentrations (0.1-5 microM), both ADP and AMP activate the channel in some patches. Examination of the nucleotide specificity of channel inhibition indicates a high selectivity for AMP over the other nucleotides tested with a rank order of potency of AMP > UMP > CMP > or = GMP. Cyclic nucleotides also modulate channel activity in a complex, concentration-dependent way. Cyclic AMP exhibits a dual effect, predominantly increasing channel activity at low concentrations (0.1-10 microM) and reducing it at higher concentrations (100 microM and 1 mM). Specificity studies indicate that the cyclic nucleotide site mediating inhibition of channel activity exhibits a strong preference for cyclic AMP over cyclic GMP, with cyclic UMP being almost equipotent with cyclic AMP. Cyclic IMP and cyclic CMP are not active at this site. The cyclic nucleotide site mediating activation of the channel shows much less nucleotide specificity than the inhibitory site, with cyclic AMP, cyclic GMP and cyclic IMP being almost equally active.

UI	MeSH Term	Description	Entries
D007340	Insulinoma	A benign tumor of the PANCREATIC BETA CELLS. Insulinoma secretes excess INSULIN resulting in HYPOGLYCEMIA.	Adenoma, beta-Cell,Insuloma,beta-Cell Tumor,Adenoma, beta Cell,Adenomas, beta-Cell,Insulinomas,Insulomas,Tumor, beta-Cell,Tumors, beta-Cell,beta Cell Tumor,beta-Cell Adenoma,beta-Cell Adenomas,beta-Cell Tumors
D007473	Ion Channels	Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.	Membrane Channels,Ion Channel,Ionic Channel,Ionic Channels,Membrane Channel,Channel, Ion,Channel, Ionic,Channel, Membrane,Channels, Ion,Channels, Ionic,Channels, Membrane
D007700	Kinetics	The rate dynamics in chemical or physical systems.
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
D010190	Pancreatic Neoplasms	Tumors or cancer of the PANCREAS. Depending on the types of ISLET CELLS present in the tumors, various hormones can be secreted: GLUCAGON from PANCREATIC ALPHA CELLS; INSULIN from PANCREATIC BETA CELLS; and SOMATOSTATIN from the SOMATOSTATIN-SECRETING CELLS. Most are malignant except the insulin-producing tumors (INSULINOMA).	Cancer of Pancreas,Pancreatic Cancer,Cancer of the Pancreas,Neoplasms, Pancreatic,Pancreas Cancer,Pancreas Neoplasms,Pancreatic Acinar Carcinoma,Pancreatic Carcinoma,Acinar Carcinoma, Pancreatic,Acinar Carcinomas, Pancreatic,Cancer, Pancreas,Cancer, Pancreatic,Cancers, Pancreas,Cancers, Pancreatic,Carcinoma, Pancreatic,Carcinoma, Pancreatic Acinar,Carcinomas, Pancreatic,Carcinomas, Pancreatic Acinar,Neoplasm, Pancreas,Neoplasm, Pancreatic,Neoplasms, Pancreas,Pancreas Cancers,Pancreas Neoplasm,Pancreatic Acinar Carcinomas,Pancreatic Cancers,Pancreatic Carcinomas,Pancreatic Neoplasm
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
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D003568	Cytidine Monophosphate	Cytidine (dihydrogen phosphate). A cytosine nucleotide containing one phosphate group esterified to the sugar moiety in the 2', 3' or 5' position.	CMP,Cytidylic Acid,2'-CMP,3'-CMP,Cytidylic Acids,2' CMP,3' CMP,Acid, Cytidylic,Acids, Cytidylic,Monophosphate, Cytidine
D006157	Guanosine Monophosphate	A guanine nucleotide containing one phosphate group esterified to the sugar moiety and found widely in nature.	5'-Guanylic Acid,Guanosine 5'-Monophosphate,5'-GMP,Guanylic Acid,5' Guanylic Acid,5'-Monophosphate, Guanosine,Acid, 5'-Guanylic,Acid, Guanylic,Guanosine 5' Monophosphate,Monophosphate, Guanosine
D000244	Adenosine Diphosphate	Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.	ADP,Adenosine Pyrophosphate,Magnesium ADP,MgADP,Adenosine 5'-Pyrophosphate,5'-Pyrophosphate, Adenosine,ADP, Magnesium,Adenosine 5' Pyrophosphate,Diphosphate, Adenosine,Pyrophosphate, Adenosine