Biomaterial Database

Origin of calcium ions involved in the generation of a slow afterhyperpolarization in bullfrog sympathetic neurones. 1983

K Kuba, and K Morita, and M Nohmi

The origin of Ca2+ that activates the Ca2+-dependent K+ conductance which is responsible for the slow afterhyperpolarization (a.h.p.) following an action potential was studied in bullfrog sympathetic ganglia. The decay phase of the a.h.p. was a graded function of the extracellular Ca2+, and showed a voltage sensitivity opposite to that of the Ca2+-dependent K+-current reported previously (Pallotta et al. 1981), indicating that it reflected the time course of an increase in intracellular free Ca2+. An a.h.p. of longer duration was generated in cells which showed more pronounced rhythmic hyperpolarizations induced by intracellular Ca2+ release. The duration of the a.h.p. recorded with electrodes filled with K3-citrate [a.h.p. (citrate)], which favors Ca2+ release, was longer than the a.h.p. recorded with KCl-filled electrodes [a.h.p. (C1)]. D-600 (50-100 microM) drastically reduced the a.h.p. (C1), but had less effect on the a.h.p. (citrate). Caffeine which facilitates Ca2+ release prolonged the a.h.p. (C1), but had less effect on the a.h.p. (citrate). The a.h.p. (citrate) showed a greater sensitivity to a low temperature than the a.h.p. (C1). Mn2+ (1-3 mM) depressed both types of a.h.ps to the same extent. These results suggest that the origin of intracellular Ca2+ for a.h.p. (C1) is mainly Ca2+ influx during an action potential, while that for the a.h.p. (citrate) is both Ca2+ entry and intracellular Ca2+ release, although the effect of Mn2+ is difficult to explain fully.

UI	MeSH Term	Description	Entries
D008345	Manganese	A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
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
D011892	Rana catesbeiana	A species of the family Ranidae (true frogs). The only anuran properly referred to by the common name "bullfrog", it is the largest native anuran in North America.	Bullfrog,Bullfrogs,Rana catesbeianas,catesbeiana, Rana
D002110	Caffeine	A methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine's most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.	1,3,7-Trimethylxanthine,Caffedrine,Coffeinum N,Coffeinum Purrum,Dexitac,Durvitan,No Doz,Percoffedrinol N,Percutaféine,Quick-Pep,Vivarin,Quick Pep,QuickPep
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
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D004533	Egtazic Acid	A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.	EGTA,Ethylene Glycol Tetraacetic Acid,EGATA,Egtazic Acid Disodium Salt,Egtazic Acid Potassium Salt,Egtazic Acid Sodium Salt,Ethylene Glycol Bis(2-aminoethyl ether)tetraacetic Acid,Ethylenebis(oxyethylenenitrile)tetraacetic Acid,GEDTA,Glycoletherdiamine-N,N,N',N'-tetraacetic Acid,Magnesium-EGTA,Tetrasodium EGTA,Acid, Egtazic,EGTA, Tetrasodium,Magnesium EGTA
D005711	Gallopamil	Coronary vasodilator that is an analog of iproveratril (VERAPAMIL) with one more methoxy group on the benzene ring.	Methoxyverapamil,D-600,D600,Elgiprona,Gallobeta,Gallopamil Hydrochloride,Prebet,Procorum,gallopamil von ct,D 600,Hydrochloride, Gallopamil
D005728	Ganglia, Sympathetic	Ganglia of the sympathetic nervous system including the paravertebral and the prevertebral ganglia. Among these are the sympathetic chain ganglia, the superior, middle, and inferior cervical ganglia, and the aorticorenal, celiac, and stellate ganglia.	Celiac Ganglia,Sympathetic Ganglia,Celiac Ganglion,Ganglion, Sympathetic,Ganglia, Celiac,Ganglion, Celiac,Sympathetic Ganglion
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential