Optical control of AMPA receptors using a photoswitchable quinoxaline-2,3-dione antagonist

Article abstract of DOI:10.1039/C6SC01621A

AMPA receptors respond to the neurotransmitter glutamate and play a critical role in excitatory neurotransmission. They have been implicated in several psychiatric disorders and have rich pharmacology. Antagonists of AMPA receptors have been explored as drugs and one has even reached the clinic. We now introduce a freely diffusible photoswitchable antagonist that is selective for AMPA receptors and endows them with light-sensitivity. Our photoswitch, ShuBQX-3, is active in its dark-adapted trans-isoform but is significantly less active as its cis-isoform. ShuBQX-3 exhibits a remarkable red-shifting of its photoswitching properties through interactions with the AMPA receptor ligand binding site. Since it can be used to control action potential firing with light, it could emerge as a powerful tool for studying synaptic transmission with high spatial and temporal precision.

Full text of DOI:10.1039/C6SC01621A

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Optical Control of AMPA Receptors Using a Photoswitchable
Quinoxaline-2,3-dione Antagonist
David M. Barber,†a Shu-An Liu,†a Kevin Gottschling,b Martin Sumser,a Michael Hollmann,b and
Dirk Trauner*a
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
AMPA receptors respond to the neurotransmitter glutamate and play a critical role in excitatory neurotransmission. They
have been implicated in several psychiatric disorders and have rich pharmacology. Antagonists of AMPA receptors have
been explored as drugs and one has even reached the clinic. We now introduce a freely diffusible photoswitchable
antagonist that is selective for AMPA receptors and endows them with light-sensitivity. Our photoswitch, ShuBQX-3, is
active in its dark-adapted trans-isoform but is significantly less active as its cis-isoform. ShuBQX-3 exhibits a remarkable
red-shifting of its photoswitching properties through interactions with the AMPA receptor ligand binding site. Since it can
be used to control action potential firing with light it could emerge as a powerful tool for studying synaptic transmission
with high spatial and temporal precision.
www.rsc.org/
neuroscience and why they have undergone extensive
development as drugs to treat psychiatric diseases.11 It would
be advantageous to use light to precisely control glutamate
Introduction
Photopharmacology is the attempt to endow biological targets
with light sensitivity using small photoswitchable molecules.1 It
has been applied to a wide variety of molecular targets,
including ion channels,2 G-protein coupled receptors (GPCRs)3
and enzymes.4 As such, it has enabled the light-dependent
control of diverse cellular processes, such as proliferation5 and
neuronal excitability.6
receptor antagonists and target their actions to specific
locations. To that end, a few caged antagonists of iGluRs have
been disclosed12 but their activation is irreversible. This
prompted us to develop a photoswitchable antagonist that can
be reversibly turned on and off. Our studies resulted in a
quinoxaline-2,3-dione derivative, termed ShuBQX-3 ‡
that
,
enables the optical control of AMPA receptor-mediated action
potential firing of hippocampal neurons.
The ionotropic glutamate receptors (iGluRs) are attractive
targets for photopharmacology due to their fundamental roles
in excitatory neurotransmission7 and their involvement in
neurodegenerative conditions and psychiatric disorders.8 The
iGluRs are natively gated by the neurotransmitter glutamate
and are divided into three subclasses due to their individual
responses to selective agonists: AMPA receptors (GluAs)
kainate receptors (GluKs) and NMDA receptors (GluNs).9
To date, all three of the iGluR subtypes have been addressed
Results and Discussion
Our design of ShuBQX-3 was based on the vast array of
antagonists for AMPA receptors that have been developed.13
These encompass compounds that exhibit non-competitive
antagonism, such as perampanel,14 which is clinically used, as
well as those that compete for the glutamate binding site.
Competitive AMPA receptor antagonists that contain the
quinoxaline-2,3-dione motif (Figure 1a,b), are an extremely
well developed family of antagonists and have undergone
extensive structure-activity relationship (SAR) studies.15
with
photopharmacology,
using
freely
diffusible
photoswitchable agonists.10 Although synthetic agonists for
neurotransmitter receptors are powerful tools, they do create
a non-physiological situation that can complicate the analyses
of neural networks. This is perhaps the reason why antagonists
of glutamatergic signaling are more widely used in
a. Department of Chemistry and Center for Integrated Protein Science, Ludwig
Maximilians University Munich, Butenandtstraße 5-13, 81377 Munich, Germany
E-mail: dirk.trauner@lmu.de
b. Department of Biochemistry I – Receptor Biochemistry, Ruhr-Universität-Bochum
Bochum 44780, Germany
† These authors contributed equally.
Electronic Supplementary Information (ESI) available: Experimental procedures
and characterisation data. See DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
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Journal Name
OH
B
R1
HO
NH2
(2)
R2
O
O2
N
CF3
Cl
O2
N
CF3
Cl
P
HC(OEt)3
p-TsOH
5: R1 = NHBoc; R2 = H
6: R1 = H; R2 = NHBoc
O2
N
CF3
Cl
HO OH
HN
HN
(68%)
O
(82%)
O
Pd(PPh3
)
4 (10 mol%)
Cl
P
P
1
HO OH
EtO OEt
4
3
O
O
Cl
(11)
H
N
O2
N
CF3
H2
N
CF3
O
CF3
R1 Pd/C, H2
R2
R1 i) Et3N,
R1
OEt
HN
HN
O
O
N
O
O
ii) EtOH/1 M HCl
P
P
R2
P
R2
EtO OEt
7: R1 = NHBoc; R2 = H (80%)
8: R1 = H; R2 = NHBoc (77%)
EtO OEt
9: R1 = NHBoc; R2 = H (89%)
10: R1 = H; R2 = NHBoc (54%)
EtO OEt
12: R1 = NH2; R2 = H (60%)
13: R1 = H; R2 = NH2 (55%)
N
H
N
H
N
(14)
O
CF3
O
CF3
N
N
t-BuONO, HCl
6 M HCl
(52%)
N
N
ShuBQX-1
CF3
O
O
N
O
O
N
12
N
N
(88%)
P
P
EtO OEt
HO OH
15
N
H
H
(14)
O
N
N
CF3
O
N
N
t-BuONO, HCl
6 M HCl
(21%)
O
O
13
O
O
N
(58%)
N
P
N
P
N
EtO OEt
HO OH
N
N
ShuBQX-2
16
Scheme 1. Synthesis of the photochromic AMPA receptor antagonists ShuBQX-1 and
ShuBQX-2.
afforded the desired meta- and para-amino substituted
quinoxaline-2,3-diones 12 and 13. Quinoxaline 12 was then
converted to meta-azobenzene 15 in an azo-coupling reaction
with N,N-dimethylaniline (14) and ShuBQX-1 was furnished
Figure 1. a) Molecular structures of quinoxaline-2,3-dione AMPA receptor
antagonists. b) Molecular structures of quinoxaline-2,3-dione AMPA receptor
antagonists with increased solubility. c) Molecular structures of the designed
photochromic AMPA receptor antagonists ShuBQX-1, ShuBQX-2 and ShuBQX-3.
after deprotection of the phosphonate ester using 6
M HCl
Starting from the parent compound DNQX, a wide array of
more selective and more soluble derivatives have been
developed, including CNQX and NBQX (Figure 1a). To increase
solubility, carboxylate or phosphonate moieties were
introduced on the nitrogen in position 4, which gave rise to
followed by reverse phase chromatography. The preparation
of ShuBQX-2 followed the same azo-coupling and deprotection
procedures as ShuBQX-1, with moderate yields of the desired
products being obtained in both reactions.
We next accomplished the synthesis of ShuBQX-3 starting
zonampanel,
LU115455 and MPQX (fanampanel) (Figure 1b).14
from phosphonate ester
cross-coupling of N-Boc protected hydrazine 17 with
phosphonate ester afforded protected hydrazine 18 in 72%
yield. Reduction of the nitro group followed by cyclization to
the quinoxaline-2,3-dione using ethyl chlorooxoacetate (11
4 (Scheme 2). A Buchwald-Hartwig
We postulated that an azobenzene moiety could be
accommodated in the 6-position of the quinoxaline-2,3-dione
core as sterically bulky substituents are tolerated in this
position. Our design hypothesis was also supported by a X-ray
crystal structure of the compound MPQX bound to a GluA2
receptor.16 The crystal structure strongly suggested that a
reasonable amount of steric bulk could be accommodated in
the 6-position of the quinoxaline-2,3-dione without interfering
with the binding of the antagonist. On the other hand, we
concluded that photoisomerization of such a moiety would
change the affinity of a ligand bound to the clamshell-like
ligand binding domain. At the very least, this could be
mediated by a reorganization of the solvation sphere upon
photoisomerization. We also added the phosphonic acid side
chain from the antagonist MPQX as it dramatically improves
the solubility of the compound in aqueous solutions.17 When
considering all of our strategic aspects, the photoswitchable
4
)
and subsequent deprotection of the phosphonate ester gave
ShuBQX-3 in 18% yield (over three steps).
With our small family of soluble, photochromic ligands in
hand, we first deduced the optimum photoswitching
wavelengths using UV-Vis spectroscopy (Figure S1) and then
determined their functional properties as light-controllable
AMPA receptor antagonists. Whole-cell patch-clamp
electrophysiology of HEK293T cells expressing GluA1-L497Y
receptors (a non-desensitizing AMPA receptor mutant)18 found
that the photochromic ligands ShuBQX-1 (5 µ
(5 µ ) are good antagonists of AMPA receptors in the
presence of glutamate (300 ). However, upon
M) and ShuBQX-2
M
µ
M
photoisomerization using blue (460 nm) and green (560 nm)
light only a small change in AMPA receptor antagonism was
antagonists ShuBQX-1, ShuBQX-2 and ShuBQX-3 were
designed (Figure 1c).
observed (Figure 2a). We then evaluated ShuBQX-3 (5 µM) and
We then set about preparing our target photoswitches, initially
focusing on ShuBQX-1 and ShuBQX-2 (Scheme 1). Starting
from dichloride
reaction furnished phosphonic acid
afford phosphonate ester . Suzuki coupling reactions using
boronic acids and , bearing Boc-protected anilines in the
meta- and para-positions, respectively, were performed to
provide biaryls and . Subsequent reduction of the nitro
1
and aminomethylphosphonic acid (
2) a SNAr
3, which was protected to
4
5
6
7
8
group followed by cyclization with ethyl chlorooxoacetate (11
)
Scheme 2. Synthesis of the photochromic AMPA receptor antagonist ShuBQX-3.
2 | J. Name., 2012, 00, 1-3
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discovered that it is an excellent photoswitchable antagonist
of AMPA receptors.
First, we determined the IC50 value of ShuBQX-3 in the
absence of light and in the presence of glutamate (300 µ
was found to be 3.1 µ (Figure S3). A very similar value (IC50
3.3 µ was obtained when illuminating ShuBQX-3 with
M). It
M
=
M
)
orange light (600 nm). At this wavelength, the photoswitch
largely resides in the trans-form. Under blue light illumination
(460 nm), which favors the cis-state of ShuBQX-3, the
antagonist was significantly less potent than in the dark-
adapted state (Figure 2). Finally, experiments conducted using
ShuBQX-3 with differing concentrations of glutamate (100 µ
M
and 1 mM) confirmed that it is a competitive antagonist of
GluA1 receptors (Figure S4). Further studies on the biological
activity of ShuBQX-3 using patch-clamp electrophysiology
showed that glutamate-induced currents are completely
blocked in its trans-form. Upon illumination with 460 nm light,
50% of the glutamate-induced current (compared to the
current induced in the absence of ShuBQX-3) could be
released (Figure 2a). We then determined the action spectrum
of ShuBQX-3 in the presence of glutamate. When the
wavelength was switched between orange light (600 nm) and
different wavelengths of purple blue and green light (400-500
nm), we observed large differences in current (Figure 2b). The
maximum inward current was consistently observed when
illuminating with 440 nm or 460 nm (Figure S5) whereas
minimum inward currents were observed using long
wavelength light or in the dark. Reversible photoactivation of
AMPA receptors with ShuBQX-3 is robust and could be
repeated over many times without any significant loss of
receptor antagonism (Figure 2c). Highly reproducible
photoswitching of ShuBQX-3 was also obtained when
operating in current-clamp mode (Figure S6).
To determine the selectivity profile of ShuBQX-3 (5 µ
dark state, we evaluated its effects on Xenopus oocytes
expressing variety of glutamate receptors (Figure 3).
ShuBQX-3 (5 µ ) showed excellent antagonism of all GluA1-
M) in its
a
M
containing receptors that were tested (85-93%). By contrast,
the amount of antagonism observed at this concentration on
the GluK2 receptor was significantly reduced (25%) when
inducing the current using glutamate (100 µ
M). Reducing the
concentration of glutamate (30 µM) increased the amount of
antagonism exhibited by ShuBQX-3 at the GluK2 receptor
(49%). Thus, indicating that the dark state of ShuBQX-3 is a
competitive antagonist of the GluK2 receptor. Additionally,
ShuBQX-3 (5 µ
M
) was evaluated against several GluN1-1a-
) displayed minimal
containing receptors. ShuBQX-3 (5 µ
M
antagonism at the GluN1-1a-containing glutamate receptors,
demonstrating that ShuBQX-3 is partially selective for AMPA
receptors over kainate, whilst having significantly reduced
levels of antagonism at NMDA receptors.
With the full evaluation of ShuBQX-3 in transfected HEK293T
cells and Xenopus oocytes complete, we set out to
demonstrate that ShuBQX-3 could control native AMPA
receptors in excitable cells. For these experiments we used
acute mouse brain slice preparations and whole cell patch-
clamp electrophysiology of hippocampal CA1 neurons.
Pleasingly, when ShuBQX-3 (10 µM) and glutamate (100 µM)
were locally applied in a brain slice preparation, the induced
action potential firing of a single neuron could be effectively
controlled by switching between blue (460 nm) and orange
(620 nm) light (Figure 4). The NMDA-receptor antagonist AP-5
Figure 2.
(50 µM) was locally added to ensure that the action potential
firing was not caused by any interactions between the NMDA
receptors and glutamate. Additionally, we were able to
optically control hippocampal CA1 neurons when using AMPA
as the agonist (Figure S7). Demonstrating that ShuBQX-3 is
selective for AMPA receptors.
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20-fold excess of
L
-arginine. The optimum photoswitching
wavelengths of ShuBQX-3 were now demonstrated to be 460
nm and 600 nm (Figure 5b). When -arginine was replaced by
L
guanidine, a similar bathochromic shift was observed (Figure
S8), substantiating our hypothesis. UV-Vis experiments
conducted with the diethyl phosphonate of ShuBQX-3 showed
that the phosphonic acid side chain is not crucial for the
interaction (Figure S9). We also measured the thermal
relaxation rate of ShuBQX-3 in the presence of L-arginine (τ =
1.68 min) and found it to be faster than the rate of ShuBQX-3
alone (τ = 7.37 min). This is in accordance to the rate
acceleration of red-shifted azobenzenes in comparison to their
non red-shifted analogues.20 To the best of our knowledge,
this is the first example of an azobenzene-based photoswitch
to exhibit such red-shifting properties. Control experiments
Figure 4. Optical control of action potential firing in hippocampal CA1 neurons using
ShuBQX-3 (10 µM) in the presence of glutamate (100 µM) and AP-5 (50 µM).
The action spectrum of ShuBQX-3 is noteworthy, as we
observed
a significant difference between the optimal
photoswitching wavelengths established by the UV-Vis
experiments and the physiological patch-clamp experiments.
using ShuBQX-3 (50 µM) dissolved in Ringer’s solution showed
almost no change in the absorption maximum (Figure S1). Our
findings suggest that the interaction between R-485 and the
quinoxaline-2,3-dione is responsible for the bathochromic shift
In our UV-Vis experiments, a solution of ShuBQX-3 (50 µ
M in
DMSO) displayed optimal photoswitching at 380 nm (trans to
cis) and 460 nm (cis to trans), with a λmax = 365 nm for the
trans-isomer (Figure 5a, S1). However, in the patch-clamp
experiments in HEK293T cells expressing the GluA1 receptor,
in the action spectrum of ShuBQX-3
.
ShuBQX-3 exhibited
a bathochromic shift in its action
Conclusions
spectrum, with optimal photoswitching now taking place when
illuminating with 460 nm and 600 nm light.19 In an attempt to
ascertain why this bathochromic shift was occurring, we
consulted the X-ray crystal structure of the non-
photoswitchable antagonist MPQX bound to a GluA2 receptor
(Figure 5c).16 The structure features prominent interaction
between the guanidinium moiety of arginine R-485, which is
also involved in glutamate binding, and the quinoxaline-2,3-
dione core of MPQX. We therefore postulated that this
interaction could have an effect on the photoswitching
properties of ShuBQX-3 when it is bound to the GluA1
receptor.
In summary, we have developed a photochromic antagonist
that permits the precise optical control of AMPA receptors.
Our photoswitch, ShuBQX-3, is active as its trans-isomer and is
converted to its cis-isomer using blue light illumination
enabled by red-shifting upon binding to AMPA receptors.
ShuBQX-3 expands the photopharmacology of iGluRs and
demonstrates that potent photoswitchable antagonists for
these receptors can be developed. We envision that ShuBQX-3
will be an important tool for studying the function of AMPA
receptors in vivo.
To probe this possible interaction, we took the UV-Vis solution
Acknowledgements
of ShuBQX-3 (50 µ
M in DMSO) and doped it with L-arginine.
Indeed, a bathochromic shift of 75 nm (λmax = 440 nm) in the
UV-Vis spectrum of ShuBQX-3 was observed (Figure 5a) with a
D.M.B. gratefully acknowledges the European Commission for
a Marie Skłodowska-Curie Intra-European Fellowship (PIEF-GA-
2013-627990). S.L. thanks the Studienstiftung des deutschen
Volkes for a PhD studentship. D.T. thanks the Munich Centre
for Integrated Protein Science (CIPSM) and the European
Research Council (Advanced Grant 268795). K.G. was funded
by the International Graduate School of Neuroscience (IGSN)
at the Ruhr University Bochum and the RUB Research School.
We thank Dr. Laura Salonen for initial studies toward the
synthesis of ShuBQX-1 and Luis de la Osa de la Rosa for
technical assistance. In addition, we are grateful to Dr.
Johannes Broichhagen for helpful discussions and Philipp
Leippe for assistance with the UV-Vis experiments.
Live subject statement
All animal procedures were performed in accordance with the
guidelines of the Regierung Oberbayern/ the Tierschutzgesetz
(TierSchG)
and
the
TierschutzVersuchstierverordnung
(TierSchVersV).
4 | J. Name., 2012, 00, 1-3
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M. R. Helix, E. Y. Isacoff, D. Trauner, J. Am. Chem. Soc.
2007, 129, 260-261; c) P. Stawski, M. Sumser, D. Trauner,
Angew. Chem. Int. Ed. 2012, 51, 5748-5751; d) L. Laprell,
E. Repak, V. Franckevicius, F. Hartrampf, J. Terhag, M.
Hollmann, M. Sumser, N. Rebola, D. A. DiGregorio, D.
Trauner, Nat Commun 2015, 6.
Notes and references
‡ ShuBQX is a combination of the names of the authors D.M.B.
and S.L. and the antagonist MPQX.
1
a) T. Fehrentz, M. Schönberger, D. Trauner, Angew. Chem.
Int. Ed. 2011, 50, 12156-12182; b) A. A. Beharry, G. A.
Woolley, Chem. Soc. Rev. 2011, 40, 4422-4437; c) C.
Brieke, F. Rohrbach, A. Gottschalk, G. Mayer, A. Heckel,
Angew. Chem. Int. Ed. 2012, 51, 8446-8476; d) W.
Szymański, J. M. Beierle, H. A. V. Kistemaker, W. A.
Velema, B. L. Feringa, Chem. Rev. 2013, 113, 6114-6178;
e) W. A. Velema, W. Szymanski, B. L. Feringa, J. Am. Chem.
Soc. 2014, 136, 2178-2191.
11
12
P. K. Y. Chang, D. Verbich, R. A. McKinney, Eur. J. Neurosci.
2012, 35, 1908-1916.
a) K. P. S. J. Murphy, G. P. Reid, D. R. Trentham, T. V. P.
Bliss, J. Physiol. 1997, 504, 379-385; b) J. E. Reeve, M. M.
Kohl, A. Rodríguez-Moreno, O. Paulsen, H. L. Anderson,
Commun. Integr. Biol 2012, 5, 240-242; c) J. J. Chambers,
H. Gouda, D. M. Young, I. D. Kuntz, P. M. England, J. Am.
Chem. Soc. 2004, 126, 13886-13887.
a) S. S. Nikam, B. E. Kornberg, Curr. Med. Chem. 2001, 8,
155-170; b) P. Stawski, H. Janovjak, D. Trauner, Bioorg.
Med. Chem. 2010, 18, 7759-7772.
S. Hibi, K. Ueno, S. Nagato, K. Kawano, K. Ito, Y. Norimine,
O. Takenaka, T. Hanada, M. Yonaga, J. Med. Chem. 2012,
55, 10584-10600.
D. Catarzi, V. Colotta, F. Varano, Med. Res. Rev. 2007, 27,
239-278.
A. I. Sobolevsky, M. P. Rosconi, E. Gouaux, Nature 2009,
462, 745-756.
L. Turski, A. Huth, M. Sheardown, F. McDonald, R.
Neuhaus, H. H. Schneider, U. Dirnagl, F. Wiegand, P.
Jacobsen, E. Ottow, Proc. Natl. Acad. Sci. 1998, 95, 10960-
10965.
2
a) M. Schönberger, M. Althaus, M. Fronius, W. Clauss, D.
Trauner, Nat Chem 2014, 6, 712-719; b) J. Broichhagen,
M. Schönberger, S. C. Cork, J. A. Frank, P. Marchetti, M.
Bugliani, A. M. J. Shapiro, S. Trapp, G. A. Rutter, D. J.
Hodson, D. Trauner, Nat Commun 2014, 5; c) A.
Damijonaitis, J. Broichhagen, T. Urushima, K. Hüll, J.
Nagpal, L. Laprell, M. Schönberger, D. H. Woodmansee, A.
Rafiq, M. P. Sumser, W. Kummer, A. Gottschalk, D.
Trauner, ACS Chemical Neuroscience 2015, 6, 701-707.
a) M. Schönberger, D. Trauner, Angew. Chem. Int. Ed.
2014, 53, 3264-3267; b) S. Pittolo, X. Gómez-Santacana, K.
Eckelt, X. Rovira, J. Dalton, C. Goudet, J.-P. Pin, A. Llobet,
J. Giraldo, A. Llebaria, P. Gorostiza, Nat. Chem. Biol. 2014,
10, 813-815.
a) C. Falenczyk, M. Schiedel, B. Karaman, T. Rumpf, N.
Kuzmanovic, M. Grotli, W. Sippl, M. Jung, B. Konig,
Chemical Science 2014, 5, 4794-4799; b) B. Reisinger, N.
Kuzmanovic, P. Löffler, R. Merkl, B. König, R. Sterner,
Angew. Chem. Int. Ed. 2014, 53, 595-598; c) X. Chen, S.
Wehle, N. Kuzmanovic, B. Merget, U. Holzgrabe, B. König,
C. A. Sotriffer, M. Decker, ACS Chemical Neuroscience
2014, 5, 377-389; d) J. Broichhagen, I. Jurastow, K. Iwan,
W. Kummer, D. Trauner, Angew. Chem. Int. Ed. 2014, 53,
7657-7660.
13
14
15
16
17
3
4
18
19
Y. Stern-Bach, S. Russo, M. Neuman, C. Rosenmund,
Neuron 1998, 21, 907-918.
We also conducted patch-clamp experiments in which
ShuBQX-1 and ShuBQX-2 were irradiated with varying
wavelengths of light but no bathochromic shift was
observed for either of these compounds (Figure S2).
J. García-Amorós, D. Velasco, Beilstein J. Org. Chem. 2012,
8, 1003-1017.
20
5
6
M. Borowiak, W. Nahaboo, M. Reynders, K. Nekolla, P.
Jalinot, J. Hasserodt, M. Rehberg, M. Delattre, S. Zahler, A.
Vollmar, D. Trauner, O. Thorn-Seshold, Cell 2015, 162,
403-411.
a) A. Polosukhina, J. Litt, I. Tochitsky, J. Nemargut, Y.
Sychev, I. De Kouchkovsky, T. Huang, K. Borges, D.
Trauner, Russell N. Van Gelder, Richard H. Kramer,
Neuron 2012, 75, 271-282; b) A. Mourot, T. Fehrentz, Y. Le
Feuvre, C. M. Smith, C. Herold, D. Dalkara, F. Nagy, D.
Trauner, R. H. Kramer, Nat Meth 2012, 9, 396-402; c) I.
Tochitsky, A. Polosukhina, Vadim E. Degtyar, N. Gallerani,
Caleb M. Smith, A. Friedman, Russell N. Van Gelder, D.
Trauner, D. Kaufer, Richard H. Kramer, Neuron 2014, 81,
800-813.
7
8
S. F. Traynelis, L. P. Wollmuth, C. J. McBain, F. S. Menniti,
K. M. Vance, K. K. Ogden, K. B. Hansen, H. Yuan, S. J.
Myers, R. Dingledine, Pharmacol. Rev. 2010, 62, 405-496.
a) S. A. Lipton, Nat Rev Drug Discov 2006, 5, 160-170; b) A.
Alt, E. S. Nisenbaum, D. Bleakman, J. M. Witkin, Biochem.
Pharmacol. 2006, 71, 1273-1288; c) D. E. Jane, D. Lodge,
G. L. Collingridge, Neuropharmacol 2009, 56, 90-113.
R. W. Gereau, G. T. Swanson, The Glutamate Receptors,
Humana Press, Totowa, 2008.
9
10
a) A. Reiner, J. Levitz, E. Y. Isacoff, Curr. Opin. Pharmacol.
2015, 20, 135-143; b) M. Volgraf, P. Gorostiza, S. Szobota,
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