Cyclothiazide and GYKI 52466 modulate AMPA receptor-mediated apoptosis in cortical neuronal cultures.
In neocortical neuronal cultures, (S)-AMPA caused neurotoxicity which was concentration-dependent, receptor-mediated, slow and apoptotic in nature. (S)-AMPA (3-600 microM) failed to produce rapid neuronal swelling, but morphological observations and monitoring of viability at 24-72 h revealed 50% cell death consistent with apoptosis. (S)-AMPA induced cell shrinkage, neurite blebbing and nuclear condensation. Cyclothiazide (50 and 100 microM), which blocks AMPA receptor desensitization potentiated excitotoxicity with 75% of neurones undergoing slow death. The AMPA-selective antagonist GYKI 52466 (10-50 microM), attenuated (S)-AMPA-mediated neurotoxicity. DNA condensation, a hallmark of apoptosis, was found by labelling neurones with the DNA binding dye 4,6-diamidino-2-phenylindole HCl (DAPI). Gel electrophoresis revealed DNA fragmentation, which was increased by cyclothiazide and reduced by GYKI 52466 and cycloheximide. Overstimulation of the AMPA receptor produces a novel form of neuronal death, which is apoptotic, very slow in nature, and which could contribute to various neuropathologies.
John
C A
CA
Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
Beart
P M
PM
Giardina
S F
SF
Pascoe
C J
CJ
Cheung
N S
NS
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001569:Benzodiazepines; D001581:Benzothiadiazines / Q000494:pharmacology*; D002478:Cells, Cultured; D018698:Glutamic Acid / Q000378:metabolism; D051379:Mice; D019579:Neocortex / Q000187:drug effects / Q000196:embryology; D009474:Neurons / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000494:pharmacology; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000378:metabolism*
D014151:Anti-Anxiety Agents; D001581:Benzothiadiazines; D018696:Neuroprotective Agents; D018091:Receptors, AMPA; C061950:GYKI 52466; D001569:Benzodiazepines; D018698:Glutamic Acid; C004639:cyclothiazide