Cytosolic free calcium in hippocampal CA3 pyramidal cells.
The dynamics of cytosolic free Ca2+ ([Ca2+]i) of single voltage-clamped CA3 pyramidal cells in hippocampal slice cultures is reviewed. [Ca2+]i amounts to about 30 nM at resting membrane potential and increases slowly when the membrane potential is clamped at more positive values (up to 500 nM at -30 mV). Short lasting depolarizations (40-100 ms) induce a transient rise in [Ca2+]i which activates a slow aftercurrent (IAHP). The muscarinic or beta-adrenergic depression of IAHP is not accompanied by any change in the dynamics of Ca2+ and appears, therefore, to result primarily from an inhibition of the K(+)-current itself or of the ability of Ca2+ to activate the current. At higher concentrations than those required to inhibit IAHP, muscarine produces a pronounced inward current and this is accompanied by a rise in resting [Ca2+]i concentration.
Knöpfel
T
T
Brain Research Institute, University of Zürich, Switzerland.
Charpak
S
S
Brown
D A
DA
Gähwiler
B H
BH
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism*; D004558:Electric Stimulation; D006624:Hippocampus / Q000378:metabolism / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials; D051381:Rats
D002118:Calcium