Intracellular calcium redistribution accompanies changes in total tissue Na+, K+ and water during the first two hours of in vitro incubation of hippocampal slices.
Changes of total tissue water, Ca, Na and K contents were monitored in whole transverse hippocampal slices of the guinea-pig during the first 2 h of in vitro incubation. A brief, 75% increase in tissue Ca was noted during the initial 15 min of maintenance, in contrast to a permanent increase of sodium and water contents, coupled to simultaneous decrease of potassium level. The rate of tissue Na, K and water changes comprised a rapid phase at the first 10-20 min, parallel with the increase of the tissue Ca content, and a slow phase during the rest of the incubation period. Development of specific morphological alterations, representative of ischemic/hypoxic lesions and a translocation of calcium from cytoplasm to mitochondria and endoplasmic reticulum during slice maintenance, was also detected by electron microscopy. A two-step mechanism might explain the development of a new steady-state total calcium content of slices. in which the cellular Ca2+ uptake at the beginning of incubation, likely triggered by hypoxic/ ischemic trauma of slice preparation, is followed by a balanced Ca2+ influx, extrusion and sequestration (predominantly into mitochondria and endoplasmic reticulum) during maintenance.
Siklós
L
L
Laboratory of Molecular Neurobiology, Institute of Biophysics, Biological Research Center, Szeged, Hungary.
Kuhnt
U
U
Párducz
A
A
Szerdahelyi
P
P
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D046508:Culture Techniques; D005260:Female; D006168:Guinea Pigs; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution; D014867:Water / Q000378:metabolism*
D014867:Water; D012964:Sodium; D011188:Potassium; D002118:Calcium