Anoxia selectively depresses excitatory synaptic transmission in hippocampal slices.
EPSPs/IPSPs were recorded with intracellular electrodes from CA1 neurons close to site of stimulation. Brief anoxia (3 min) abolished EPSPs but reduced IPSPs by 64.8 +/- 4.0% (n = 10); the remaining IPSP was presumed to be monosynaptic. The effects of anoxia on purely monosynaptic IPSPs were examined after pharmacological blockade of excitatory synaptic transmission with 2 mM kynurenate or 20 microM CNQX + 20 microM APV. In these tests, after 3 min of anoxia the slopes of IPSPs vs. membrane potential were reduced by only 38.2 +/- 4.3% (n = 12). The present study demonstrates that, contrary to previous reports, inhibitory synaptic transmission is quite resistant to anoxia.
Zhu
P J
PJ
Anaesthesia Research, Department, McGill University, Montréal, Qué., Canada.
Krnjević
K
K
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology*; D066298:In Vitro Techniques; D007736:Kynurenic Acid / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*
D011810:Quinoxalines; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D015763:2-Amino-5-phosphonovalerate; D007736:Kynurenic Acid; D001640:Bicuculline