ACET is a highly potent and specific kainate receptor antagonist: characterisation and effects on hippocampal mossy fibre function.
Kainate receptors (KARs) are involved in both NMDA receptor-independent long-term potentiation (LTP) and synaptic facilitation at mossy fibre synapses in the CA3 region of the hippocampus. However, the identity of the KAR subtypes involved remains controversial. Here we used a highly potent and selective GluK1 (formerly GluR5) antagonist (ACET) to elucidate roles of GluK1-containing KARs in these synaptic processes. We confirmed that ACET is an extremely potent GluK1 antagonist, with a Kb value of 1.4+/-0.2 nM. In contrast, ACET was ineffective at GluK2 (formerly GluR6) receptors at all concentrations tested (up to 100 microM) and had no effect at GluK3 (formerly GluR7) when tested at 1 microM. The X-ray crystal structure of ACET bound to the ligand binding core of GluK1 was similar to the UBP310-GluK1 complex. In the CA1 region of hippocampal slices, ACET was effective at blocking the depression of both fEPSPs and monosynaptically evoked GABAergic transmission induced by ATPA, a GluK1 selective agonist. In the CA3 region of the hippocampus, ACET blocked the induction of NMDA receptor-independent mossy fibre LTP. To directly investigate the role of pre-synaptic GluK1-containing KARs we combined patch-clamp electrophysiology and 2-photon microscopy to image Ca2+ dynamics in individual giant mossy fibre boutons. ACET consistently reduced short-term facilitation of pre-synaptic calcium transients induced by 5 action potentials evoked at 20-25Hz. Taken together our data provide further evidence for a physiological role of GluK1-containing KARs in synaptic facilitation and LTP induction at mossy fibre-CA3 synapses.
Dargan
Sheila L
SL
MRC Centre for Synaptic Plasticity, University of Bristol, Bristol BS8 1TD, UK. sheila.dargan@bristol.ac.uk
Clarke
Vernon R J
VR
Alushin
Gregory M
GM
Sherwood
John L
JL
Nisticò
Robert
R
Bortolotto
Zuner A
ZA
Ogden
Ann M
AM
Bleakman
David
D
Doherty
Andrew J
AJ
Lodge
David
D
Mayer
Mark L
ML
Fitzjohn
Stephen M
SM
Jane
David E
DE
Collingridge
Graham L
GL
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000409:Alanine / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002461:Cell Line, Transformed; D018360:Crystallography, X-Ray / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation / Q000379:methods; D018690:Excitatory Amino Acid Agonists / Q000737:chemistry* / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects*; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018092:Kainic Acid Receptors / Q000037:antagonists & inhibitors* / Q000235:genetics; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D014162:Transfection; D014498:Uracil / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology
D000409:Alanine; D002118:Calcium; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018092:Kainic Acid Receptors; D014498:Uracil; C519517:1-(2-amino-2-carboxyethyl)-3-(2-carboxy-5-phenylthiophene-3-ylmethyl)-5-methylpyrimidine-2,4-dione
Acta Crystallogr D Biol Crystallogr. 2006 Apr;62(Pt 4):439-50
16552146
Neuron. 2003 Jul 17;39(2):327-41
12873388
J Neurosci. 2007 Feb 28;27(9):2212-23
17329418
Neuropharmacology. 2001 Dec;41(8):907-15
11747895
Neuroscience. 2009 Jan 12;158(1):309-23
18400404
Neuropharmacology. 2004 Jul;47(1):46-64
15165833
Nat Rev Neurosci. 2003 Jun;4(6):481-95
12778120
Science. 2001 Mar 9;291(5510):1972-6
11239159
J Med Chem. 2006 Apr 20;49(8):2579-92
16610801
Neuropharmacology. 2004 Sep;47(3):351-62
15275824
Neuropharmacology. 1998 Oct-Nov;37(10-11):1269-77
9849664
J Med Chem. 2005 Dec 1;48(24):7867-81
16302825
J Med Chem. 2007 Apr 5;50(7):1558-70
17348638
Nature. 1997 Jul 10;388(6638):182-6
9217159
Br J Pharmacol. 2003 Mar;138(6):1093-100
12684265
Science. 1998 Feb 27;279(5355):1368-70
9478900
Nature. 1998 Apr 9;392(6676):601-5
9580260
Nat Neurosci. 2002 Aug;5(8):790-5
12118256
Nature. 1997 Oct 9;389(6651):599-603
9335499
J Neurosci. 2006 Jun 28;26(26):7071-81
16807336
Nat Neurosci. 2002 Jul;5(7):657-64
12055631
J Neurosci Methods. 2007 May 15;162(1-2):346-56
17306885
Br J Pharmacol. 2002 Dec;137(7):1125-33
12429586
Neuropharmacology. 1998 Oct-Nov;37(10-11):1211-22
9849659
J Neurosci. 2004 Nov 10;24(45):10093-8
15537878
Neuropharmacology. 1996;35(12):1689-702
9076748
Mol Psychiatry. 2008 Sep;13(9):858-72
18332879
Neuron. 2006 Nov 9;52(3):497-510
17088215
Proc Natl Acad Sci U S A. 2007 Jul 17;104(29):12181-6
17620617
Neuropharmacology. 2002 Jun;42(7):889-902
12069899
Semin Cell Dev Biol. 2006 Oct;17(5):592-604
17110139
Philos Trans R Soc Lond B Biol Sci. 2003 Apr 29;358(1432):657-66
12740111
Acta Crystallogr D Biol Crystallogr. 2001 Jan;57(Pt 1):122-33
11134934
Nat Neurosci. 2003 Oct;6(10):1058-63
12947409
J Physiol. 2005 Jan 1;562(Pt 1):65-72
15513934
Neuropharmacology. 2009 Jan;56(1):90-113
18793656
Neuropharmacology. 2009 Jan;56(1):2-5
18655795
J Neurosci. 2006 Mar 29;26(13):3561-6
16571764
Neuron. 2005 Feb 17;45(4):539-52
15721240
J Neurosci. 2006 Mar 15;26(11):2852-61
16540562
Neuron. 2001 Jan;29(1):209-16
11182092
Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2126-32
15572765
J Neurosci. 1998 May 1;18(9):3386-403
9547246
Neuropharmacology. 2004 Sep;47(3):363-72
15275825
Nature. 1999 Nov 18;402(6759):297-301
10580501
Nature. 1997 Jul 10;388(6638):179-82
9217158
Neuron. 2001 Nov 20;32(4):697-709
11719209
Nat Rev Neurosci. 2008 Jun;9(6):423-36
18464791