Induction of metallothionein-I (MT-I) mRNA in primary astrocyte cultures is mediated by hypotonicity and not ethanol (EtOH) per se.
Metallothionein (MT) mRNA was determined in rat astrocyte cultures in response to ethanol (EtOH). MT-I mRNA was significantly increased after 6 h exposure to isosmotic EtOH, but not hyperosmotic EtOH. Exposure to a hyposmotic/hypotonic solution also led to a significant increase in the expression of astrocytic MT-I mRNA. The large increase in MT-I mRNA was not due to removal of extracellular NaCl, because this effect was reversed by replacement of NaCl with N-methyl D-glucamine chloride. A significant decrease in MT-I mRNA was also noted in astrocytes exposed to an EtOH-free hyperosmotic/hypertonic solution. These results suggest (1) that EtOH per se does not directly induce MT-I mRNA expression, (2) that the induction by EtOH of MT-I mRNA is secondary to hypotonicity, and (3) that hyperosmotic/hypertonic exposure is associated with reduced expression of MT-I mRNA in astrocyte cultures.
Aschner
M
M
Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157-1083, USA. maschner@bgsm.edu
Conklin
D R
DR
Aschner
J L
JL
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D015152:Blotting, Northern; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D018076:DNA, Complementary; D000431:Ethanol / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D007038:Hypotonic Solutions; D008668:Metallothionein / Q000235:genetics*; D010957:Plasmids; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012965:Sodium Chloride / Q000494:pharmacology
D002492:Central Nervous System Depressants; D018076:DNA, Complementary; D007038:Hypotonic Solutions; D012333:RNA, Messenger; D000431:Ethanol; D012965:Sodium Chloride; D008668:Metallothionein