Biomaterial Database

Cationic channels activated by extracellular ATP in rat sensory neurons. 1988

O A Krishtal, and S M Marchenko, and A G Obukhov

Department of Physico-Chemical Biology of Cell Membranes, A.A. Bogomoletz Institute of Physiology, Academy of Sciences of the Ukrainian S.S.R., Kiev, U.S.S.R.

Single channels activated by externally applied ATP were investigated in cultured sensory neurons from nodosal and spinal ganglia of rat using patch clamp and concentration clamp methods. Mean conductance of single ATP-activated channels was 17 pS when measured at a holding potential of -75 mV in saline containing 3 mM Ca2+ and 1 mM Mg2+. Sublevels of conductance were detected in some cases. The current-voltage relationship for a single channel is highly non-linear and demonstrates inwardly directed rectification. The I-V curve obtained for single channels was identical to that for macroscopic current. ATP activated the channels in the absence of divalent cations (in ethylenediaminetetra-acetate-containing medium) as well as in their presence. This indicates that ATP as a free anion can activate the receptor. Ca2+ ions decreased both macro- and microscopic ATP-activated currents. The concentration dependence of this Ca2+ effect does not fit a single site binding isotherm. The single channel current demonstrated prominent fluctuations. When measured in the 0-4 kHz frequency band the amplitude of fluctuations evaluated as a double r.m.s. was about 30% of the mean amplitude of current. The autocorrelation function for the current fluctuations in an open channel could be approximated by a single exponential with the time constant of 0.4 ms. These fluctuations did not depend on the presence of divalent cations in the external medium. The open time distribution for the investigated channels could be described by a sum of two exponentials. Presumably this reflects the existence of two subtypes of ATP-activated channels.

UI	MeSH Term	Description	Entries
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
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
D009475	Neurons, Afferent	Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.	Afferent Neurons,Afferent Neuron,Neuron, Afferent
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
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
D005727	Ganglia, Spinal	Sensory ganglia located on the dorsal spinal roots within the vertebral column. The spinal ganglion cells are pseudounipolar. The single primary branch bifurcates sending a peripheral process to carry sensory information from the periphery and a central branch which relays that information to the spinal cord or brain.	Dorsal Root Ganglia,Spinal Ganglia,Dorsal Root Ganglion,Ganglion, Spinal,Ganglia, Dorsal Root,Ganglion, Dorsal Root,Spinal Ganglion
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
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
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
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