Biomaterial Database

Interactive effects of the GABABergic modulation of calcium channels and calcium-dependent potassium channels in lamprey. 1999

J Tegnér, and S Grillner

Nobel Institute for Neurophysiology, Department of Neuroscience, Karolinska Institutet, S-171 77 Stockholm, Sweden.

The GABAB-mediated modulation of spinal neurons in the lamprey is investigated in this study. Activation of GABAB receptors reduces calcium currents through both low- (LVA) and high-voltage activated (HVA) calcium channels, which subsequently results in the reduction of the calcium-dependent potassium (KCa) current. This in turn will reduce the peak amplitude of the afterhyperpolarization (AHP). We used the modulatory effects of GABAB receptor activation on N-methyl-D-aspartate (NMDA)-induced, TTX-resistant membrane potential oscillations as an experimental model in which to separate the effects of GABAB receptor activation on LVA calcium channels from that on KCa channels. We show experimentally and by using simulations that a direct effect on LVA calcium channels can account for the effects of GABAB receptor activation on intrinsic membrane potential oscillations to a larger extent than indirect effects mediated via KCa channels. Furthermore, by conducting experiments and simulations on intrinsic membrane potential oscillations, we find that KCa channels may be activated by calcium entering through LVA calcium channels, providing that the decay kinetics of the calcium that enters through LVA calcium channels is not as slow as the calcium entering via NMDA receptors. A combined experimental and computational analysis revealed that the LVA calcium current also contributes to neuronal firing properties.

UI	MeSH Term	Description	Entries
D007798	Lampreys	Common name for the only family (Petromyzontidae) of eellike fish in the order Petromyzontiformes. They are jawless but have a sucking mouth with horny teeth.	Eels, Lamprey,Petromyzontidae,Petromyzontiformes,Eel, Lamprey,Lamprey,Lamprey Eel,Lamprey Eels
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
D008959	Models, Neurological	Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Neurologic Models,Model, Neurological,Neurologic Model,Neurological Model,Neurological Models,Model, Neurologic,Models, Neurologic
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
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
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D004351	Drug Resistance	Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.	Resistance, Drug
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
D001418	Baclofen	A GAMMA-AMINOBUTYRIC ACID derivative that is a specific agonist of GABA-B RECEPTORS. It is used in the treatment of MUSCLE SPASTICITY, especially that due to SPINAL CORD INJURIES. Its therapeutic effects result from actions at spinal and supraspinal sites, generally the reduction of excitatory transmission.	Baclophen,Chlorophenyl GABA,Apo-Baclofen,Atrofen,Ba-34,647,Ba-34647,Baclofen AWD,Baclofène-Irex,Baclospas,CIBA-34,647-BA,Clofen,Gen-Baclofen,Genpharm,Lebic,Lioresal,Liorésal,Nu-Baclo,PCP-GABA,PMS-Baclofen,beta-(Aminomethyl)-4-chlorobenzenepropanoic Acid,beta-(p-Chlorophenyl)-gamma-aminobutyric Acid,AWD, Baclofen,Apo Baclofen,ApoBaclofen,Ba34,647,Ba34647,Baclofène Irex,BaclofèneIrex,CIBA34,647BA,GABA, Chlorophenyl,Gen Baclofen,GenBaclofen,Nu Baclo,NuBaclo,PMS Baclofen,PMSBaclofen
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