Inhibitory effects of lithium ion on intracellular Ca2+ mobilization in the rat hippocampal slices.
Lithium is well established as a treatment of manic-depressive illness. As for the mechanism of action of lithium, it is proposed that lithium has effects on intracellular calcium ion (Ca2+) movement. But there are few reports in which the effects of lithium on intracellular Ca2+ movement are observed in the mammalian brain. We therefore examined the effects of lithium on intracellular Ca2+ changes in the rat hippocampal slices with a Ca2+ sensitive dye fura-2, and analyzed by means of a fluorescence microscope, a video-camera and photometrical devices. From the results of treatment with various noradrenergic agonists or antagonists, noradrenaline (NA)-induced intracellular Ca2+ change appears to be mainly mediated by alpha 1-adrenoceptors (AR) rather than alpha 2- or beta-AR. Furthermore, they are considered to be mediated by both alpha 1A-AR and alpha 1B-AR, and to be partly dependent on extracellular Ca2+. Lithium decreased NA-induced intracellular Ca2+ mobilization by attenuation of T1/2 rather than a change in the peak value, and antagonized ouabain-induced intracellular Ca2+ increase. Lithium may therefore suppress intracellular Ca2+ movement by enhancing the extrusion of intracellular Ca2+.
Okamoto
Y
Y
Department of Psychiatry and Neurosciences, Hiroshima University School of Medicine, Japan.
Kagaya
A
A
Motohashi
N
N
Yamawaki
S
S
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism*; D007477:Ions; D008094:Lithium / Q000494:pharmacology*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D009994:Osmolar Concentration; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D007477:Ions; D008094:Lithium; D002118:Calcium; D009638:Norepinephrine