Biomaterial Database

Voltage-gated sodium and calcium currents in rat osteoblasts. 1988

D Chesnoy-Marchais, and J Fritsch

Laboratoire de Neurobiologie, Ecole Normale Supérieure, Paris, France.

1. The whole-cell voltage-clamp mode of the patch-clamp technique was used to investigate the presence of voltage-gated inward currents in osteoblasts from newborn rat calvaria. 2. In K+-free solutions, three kinds of inward currents could be activated by depolarization: a voltage-gated Na+ current and two different types of Ca2+ currents. 3. The Na+ current was activated by depolarization above -40 mV in all the cells. It was reduced by half by 10 nM-TTX (tetrodotoxin). 4. In an isotonic Ba2+ external solution containing TTX, and with a Cs-EGTA internal solution buffered at pCa 8, depolarizing jumps induced both a transient Ba2+ current and a sustained Ba2+ current. The relative proportions of these two currents varied greatly among cells. 5. The transient and sustained Ba2+ currents differ with respect to their time course and their voltage dependence. 6. The depolarization-activated inward currents were also observed under more physiological conditions, in the presence of only 2 mM-external Ca2+ and with a K+ internal solution buffered at pCa 7. 7. A few records obtained in current clamp showed that it is possible to induce action potentials in osteoblasts.

UI	MeSH Term	Description	Entries
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
D010006	Osteoblasts	Bone-forming cells which secrete an EXTRACELLULAR MATRIX. HYDROXYAPATITE crystals are then deposited into the matrix to form bone.	Osteoblast
D010010	Osteoclasts	A large multinuclear cell associated with the BONE RESORPTION. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in CEMENTUM resorption.	Odontoclasts,Cementoclast,Cementoclasts,Odontoclast,Osteoclast
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
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.
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
D001464	Barium	An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23
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
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