Biomaterial Database

Pharmacological dissection of multiple types of Ca2+ channel currents in rat cerebellar granule neurons. 1995

A Randall, and R W Tsien

Department of Molecular and Cellular Physiology, Beckman Center, Stanford University Medical Center, California 94305, USA.

The diversity of Ca2+ channel types in rat cerebellar granule neurons was investigated with whole-cell recordings (5 mM external Ba2+). Contributions of five different high-voltage-activated Ca2+ channel current components were distinguished pharmacologically. Nimodipine-sensitive L-type current and omega-CTx-GVIA-sensitive N-type current contributed 15 and 20% of the total current, respectively. The bulk of the remaining current (46%) was inhibited by omega-Aga-IVA. The current blocked by this toxin was further subdivided into two components, P-type and Q-type, on the basis of differences in their inactivation kinetics and sensitivity to omega-Aga-IVA. P-Type current was noninactivating during 0.1 sec depolarizations, half-blocked at about 1-3 nM omega-Aga-IVA, and contributed approximately 11% of the total current; Q-type current was prominently inactivating, half-blocked at approximately 90 nM omega-Aga-IVA, and comprised 35% of the total current. Both P- and Q-type currents were potently inhibited by the Conus magus toxin omega-CTx-MVIIC. A current component resistant to all of the aforementioned blockers (R-type) displayed more rapid inactivation than the other components and constituted 19% of the total current. The Q-type current, the largest of the current components in the granule neurons, resembles currents that can be generated in Xenopus oocytes by expression of cloned alpha 1A subunits.

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
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D009553	Nimodipine	A calcium channel blockader with preferential cerebrovascular activity. It has marked cerebrovascular dilating effects and lowers blood pressure.	Admon,Bay e 9736,Brainal,Calnit,Kenesil,Modus,Nimodipin Hexal,Nimodipin-ISIS,Nimodipino Bayvit,Nimotop,Nymalize,Remontal,Bayvit, Nimodipino,Hexal, Nimodipin,Nimodipin ISIS,e 9736, Bay
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D002121	Calcium Channel Blockers	A class of drugs that act by selective inhibition of calcium influx through cellular membranes.	Calcium Antagonists, Exogenous,Calcium Blockaders, Exogenous,Calcium Channel Antagonist,Calcium Channel Blocker,Calcium Channel Blocking Drug,Calcium Inhibitors, Exogenous,Channel Blockers, Calcium,Exogenous Calcium Blockader,Exogenous Calcium Inhibitor,Calcium Channel Antagonists,Calcium Channel Blocking Drugs,Exogenous Calcium Antagonists,Exogenous Calcium Blockaders,Exogenous Calcium Inhibitors,Antagonist, Calcium Channel,Antagonists, Calcium Channel,Antagonists, Exogenous Calcium,Blockader, Exogenous Calcium,Blocker, Calcium Channel,Blockers, Calcium Channel,Calcium Blockader, Exogenous,Calcium Inhibitor, Exogenous,Channel Antagonist, Calcium,Channel Blocker, Calcium,Inhibitor, Exogenous Calcium
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
D002531	Cerebellum	The part of brain that lies behind the BRAIN STEM in the posterior base of skull (CRANIAL FOSSA, POSTERIOR). It is also known as the "little brain" with convolutions similar to those of CEREBRAL CORTEX, inner white matter, and deep cerebellar nuclei. Its function is to coordinate voluntary movements, maintain balance, and learn motor skills.	Cerebella,Corpus Cerebelli,Parencephalon,Cerebellums,Parencephalons
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
D005260	Female		Females