Glial swelling in ischemia: a hypothesis.
On the basis of experiments with primary cultures of mouse astrocytes with conventional K(+)-sensitive intracellular microelectrodes involving 'chemical ischemia' (antimycin a and sodium fluoride treatment), a model of ischemia is presented. According to this model, ischemia has no significant direct effect during the first 10 min on astrocytes; neurones, however, lose a major part of their K+ into the ECS. This leads to an astrocytic depolarization, which in turn activates astrocytic anion channels. This will result in passive, Donnan-mediated K+, Cl- and HCO3- fluxes into astrocytes, which in turn causes swelling and a collapse of the ECS. Arguments are put forward that this may explain the swelling of astrocytic endfeet, which occurs very early in an ischemic insult.
Walz
W
W
Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
Klimaszewski
A
A
Paterson
I A
IA
D000818:Animals; D001253:Astrocytes / Q000473:pathology; D002545:Brain Ischemia / Q000473:pathology*; D048429:Cell Size / Q000502:physiology; D002478:Cells, Cultured; D051379:Mice; D009457:Neuroglia / Q000473:pathology*