Reduction in bioelectric GABA and NMDA responses in organotypic neocortical explants by chronic elevation of potassium.
Long-term cultures of organotypic neonatal rat neocortex slices were maintained in a serum-free medium supplemented with 25 mM potassium. Such cultures continue to be bioelectrically silent upon return to a 5 mM potassium medium. The absence of responses to pressure ejected gamma-aminobutyric acid (GABA) and N-methyl-D-aspartate (NMDA) from neurons in treated explants suggests that one consequence of chronic depolarization is a reduction in the density of postsynaptic transmitter receptors. [3H]Muscimol binding to neocortical membrane preparations shows a large reduction in the binding of this agonist to GABAA receptors. These data show that the quantitative expression of at least one neurotransmitter receptor, the GABAA receptor, relies on voltage-dependent activity in developing neocortical neurons in vitro.
Baker
R E
RE
Netherlands Institute for Brain Research, Amsterdam.
Ruijter
J M
JM
Walden
J
J
Bingmann
D
D
Straub
H
H
Speckmann
E J
EJ
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D002462:Cell Membrane / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009118:Muscimol / Q000378:metabolism; D016202:N-Methylaspartate / Q000378:metabolism* / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009924:Organ Culture Techniques; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D011963:Receptors, GABA-A / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000494:pharmacology
D011963:Receptors, GABA-A; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D011188:Potassium