Developmental changes in depolarization-mediated AMPA receptor modifications and potassium-induced long-term potentiation.
In the present study, we examined the KCl-induced increase in [3H] amino-3-hydroxy-5-methylisoxazole-4-propionate ([3H]AMPA) binding in telencephalic synaptoneurosomes and potentiation of synaptic transmission (KLTP) in hippocampal slices during development in rats. As previously reported, KCI-induced depolarization of telencephalic synaptoneurosomes resulted in a 40 +/- 5% increase in [3H]AMPA binding to membrane fractions in adult rats (3 months old). KCI-induced increase in [3H]AMPA binding was reduced to 24 +/- 5% and 15 +/- 5% at postnatal days (PND) 25-30 and PND 15-20 respectively, and was only 6 +/- 5% at PND 5-10. KLTP in area CA1 of hippocampus was most pronounced in adult slices (40 +/- 5%), and was reduced to 30 +/- 5% in slices prepared from PND 25-30 animals; KCI-induced LTP was absent in CA1 hippocampal slices prepared from PND 5-10 animals (3 +/- 5%). The decrease in KCI-induced changes in AMPA receptor binding in young animals was also associated with an altered capacity of the bee venom peptide, mellitin (a phospholipase A2 (PLA2) activator), to increase [3H]AMPA binding in synaptoneurosomes. The smaller effect of mellitin on [3H]AMPA binding in young animals was not due to a decreased ability of this peptide to release [3H]arachidonate from synaptoneuro-somes. The parallel modifications in the extent of depolarization-induced change in AMPA receptor binding and excitatory synaptic transmission during development further support the hypothesis that alterations in AMPA receptor properties may play a critical role in synaptic plasticity.
Chabot
C
C
Départment de Chimie-Biologie, Université du Québec à Trois-Rivières, Canada.
Bernard
J
J
Normandin
M
M
Ohayon
M
M
Baudry
M
M
Massicotte
G
G
D000367:Age Factors; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D004594:Electrophysiology; D006624:Hippocampus / Q000196:embryology / Q000254:growth & development*; D017774:Long-Term Potentiation / Q000502:physiology*; D008555:Melitten / Q000494:pharmacology; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure; D009924:Organ Culture Techniques; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D011189:Potassium Chloride / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000187:drug effects / Q000502:physiology*; D013574:Synaptosomes / Q000737:chemistry; D014316:Tritium
D018091:Receptors, AMPA; D014316:Tritium; D008555:Melitten; D016718:Arachidonic Acid; D011189:Potassium Chloride; D010741:Phospholipases A; D054467:Phospholipases A2