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Synaptic transmission at nicotinic acetylcholine receptors in rat hippocampal organotypic cultures and slices
Author(s) -
Hefft Stefan,
Hulo Sophie,
Bertrand Daniel,
Muller Dominique
Publication year - 1999
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1999.769ab.x
Subject(s) - methyllycaconitine , nicotinic agonist , ampa receptor , neurotransmission , nbqx , chemistry , nicotinic antagonist , picrotoxin , neuroscience , tetrodotoxin , gabaa receptor , nmda receptor , biophysics , receptor , biology , nicotinic acetylcholine receptor , biochemistry
1 Whole‐cell clamp recordings of the compound synaptic current elicited by afferent stimulation of Schaffer collaterals showed that blockade of the NMDA, AMPA and GABA A receptor‐mediated components by 6‐nitro‐7‐sulphamoyl‐ benzo( f )quinoxaline‐2,3‐dione (NBQX), 3‐(( R )‐2‐carboxypiperazine‐4‐yl)propyl‐1‐phosphonate (R‐CPP) and picrotoxin, respectively, left a small residual current in 39 out of 41 CA1 pyramidal neurones in organotypic cultures and 9 out of 16 CA1 cells in acutely prepared slices. 2 This current represented 2.9 ± 0.4% of the compound evoked synaptic response in organoypic cultures and 1.4 ± 0.5% in slices. It was characterized by a slightly rectifying I–V curve and a reversal potential of 3.4 ± 5.1 mV. 3 This residual current was insensitive to blockers of GABA B , purinergic, muscarinic and 5‐HT3 receptors, but it was essentially blocked by the nicotinic receptor antagonist d‐ tubocurarine (91 ± 4% blockade; 20 μ m ), and partly blocked by α‐bungarotoxin (200 n m ) and methyllycaconitine (10 n m ), two antagonists with a higher selectivity for α7 subunit‐containing nicotinic receptors (48 ± 3% and 55 ± 11% blockade, respectively). 4 The residual current was of synaptic origin, since it occurred after a small delay; its amplitude depended upon the stimulation intensity and it was calcium dependent and blocked by the sodium channel antagonist tetrodotoxin. 5 We conclude that afferent stimulation applied in the stratum radiatum evokes in some hippocampal neurones a small synaptic current mediated by activation of neuronal nicotinic receptors.