Incubation of tissue slices in the absence of Ca2+ and Mg2+ can cause nonspecific damage.
Superfusion of striatal slices with a medium deficient in Ca2+ and Mg2+ caused a large and sustained increase in release of lactate dehydrogenase, a finding indicative of the disruption of plasma membranes. This was associated with an efflux of dopamine (DA) and the depletion of DA from the tissue. In addition, whereas DA efflux was stimulated by either D-amphetamine (10 microM) or L-glutamate (10 mM) in the absence of Ca2+, these effects were greatly reduced when Mg2+ also was withdrawn from the buffer. These results suggest that (a) incubation in a Ca2+/Mg2(+)-free buffer disrupts plasma membranes, (b) this disruption affects dopaminergic neurons as well as those of other striatal elements, and (c) the failure of a treatment to stimulate DA release in a Ca2+/Mg2(+)-free buffer cannot be used as a test of Ca2+ dependence.
Lonart
G
G
Department of Behavioral Neuroscience, University of Pittsburgh, Pennsylvania.
Zigmond
M J
MJ
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002413:Cations, Divalent / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D006652:Histological Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D002413:Cations, Divalent; D005971:Glutamates; D018698:Glutamic Acid; D000661:Amphetamine; D007770:L-Lactate Dehydrogenase; D008274:Magnesium; D002118:Calcium; D004298:Dopamine