Volume regulation of single astroglial cells in primary culture.
Relative volume variations in cultured astrocytes were examined by microspectrofluorimetry after loading the cells with the highly fluorescent intracellular probes 2,7-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF/AM) or fura-2/AM. At their isosbestic points, 450 nm and 358 nm, respectively, the probes were ion-insensitive and the fluorescent signals emitted related only to the intracellular dye concentration. By varying the excitation wavelengths, changes in intracellular pH or Ca2+ transients could be recorded simultaneously with the relative volume variations of the individual cells. After exposure to a hypotonic buffer, type 1 astrocytes swelled within 30 s and subsequently underwent regulatory volume decrease (RVD). When exposed to a hypertonic buffer, the astrocytes shrunk and exhibited regulatory volume increase (RVI). One mM glutamate induced an increase in astrocyte volume in 60 sec and evoked cytosolic Ca2+ transients but did not change intracellular pH.
Eriksson
P S
PS
Institute of Neurobiology, University of Göteborg, Sweden.
Nilsson
M
M
Wågberg
M
M
Rönnbäck
L
L
Hansson
E
E
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D048429:Cell Size; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D005452:Fluoresceins; D016257:Fura-2; D006863:Hydrogen-Ion Concentration; D006982:Hypertonic Solutions / Q000494:pharmacology; D007038:Hypotonic Solutions / Q000494:pharmacology; D009997:Osmotic Pressure; D051381:Rats
D005452:Fluoresceins; D006982:Hypertonic Solutions; D007038:Hypotonic Solutions; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D002118:Calcium; D016257:Fura-2