Agonist pharmacology of neonatal and adult glycine receptor alpha subunits: identification of amino acid residues involved in taurine activation.

Schmieden, Volker; Kuhse, Jochen; Betz, Heinrich

doi:10.1002/j.1460-2075.1992.tb05259.x

Cited by 167 publications

(169 citation statements)

References 36 publications

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“…These cells also failed to elicit chloride currents in response to GABA or glycine (each 100 M). 4 The subunit is therefore unlike the class of GABA receptor subunits (2) or the ␣ class of glycine receptor subunits (23), which can each assemble homomeric chloride channels that are gated by these ligands. When cells were cotransfected with cDNAs encoding the subunit, and either an ␣1 subunit or a ␤1 subunit, there was also a failure to detect expression of any ligand binding activities.…”

Section: Resultsmentioning

confidence: 99%

A Novel Class of GABAA Receptor Subunit in Tissues of the Reproductive System

Hedblom¹,

Kirkness²

1997

Journal of Biological Chemistry

204

137

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A novel subunit of the ␥-aminobutyrate, type A (GABA A ) receptor family has been identified in human and rat tissues. The subunit displays 30 -40% amino acid identity with known family members and represents a distinct subunit class (termed ). Transcripts of the subunit were detected in several human tissues and were particularly abundant in the uterus. The subunit protein can assemble with known GABA A receptor subunits and confer unique ligand binding properties to the recombinant receptors in which it combines. Most notably, the presence of the subunit alters the sensitivity of recombinant receptors to the endogenous steroid, pregnanolone. Identification of the subunit indicates a new target for pharmacological manipulation of GABA A receptors that are located outside of the central nervous system.

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Section: Resultsmentioning

confidence: 99%

A Novel Class of GABAA Receptor Subunit in Tissues of the Reproductive System

Hedblom¹,

Kirkness²

1997

Journal of Biological Chemistry

204

137

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“…The inhibitory amino acid, taurine, is an agonist at glycine receptors in other systems (Flint et al 1998;Hussy et al 1997;Schmieden et al 1992). Taurine has been shown to depress pyramidal cell excitability (Taber et al 1986) and have an antiepileptic activity (Cherubini et al 1981;Seiler and Sarhan 1984), although the mechanism underlying these effects is unknown.…”

Section: Taurine Is An Agonist At Glyrs In Hippocampusmentioning

confidence: 99%

“…Taurine is an abundant amino acid in hippocampus (del Rio et al 1987;Oja 1994, 1997) and interestingly, taurine is released in high levels during conditions that elicit excitotoxic cell death Oja 1994, 1997;Schurr et al 1987). Taurine has been reported to counteract excitotoxicity (Saransaari and Oja 1998a,b) and has been shown to hyperpolarize hippocampal neurons (Taber et al 1986).…”

Section: Is Taurine a Ligand Acting At Hippocampal Glyrs?mentioning

confidence: 99%

Pharmacological Characterization of Glycine-Gated Chloride Currents Recorded in Rat Hippocampal Slices

Chattipakorn

McMahon

2002

Journal of Neurophysiology

139

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Chattipakorn, Siriporn C. and Lori L. McMahon. Pharmacological characterization of glycine-gated chloride currents recorded in rat hippocampal slices. J Neurophysiol 87: 1515-1525, 2002; 10.1152/jn. 00365.2001. An inhibitory role for strychnine-sensitive glycine-gated chloride channels (GlyRs) in mature hippocampus has been overlooked, largely due to the misconception that GlyR expression ceases early during development and to few functional studies demonstrating their presence. As a result, little is known regarding the physiological and pharmacological properties of native GlyRs expressed by hippocampal neurons. In this study, we used pharmacological tools and whole cell patch-clamp recordings of CA1 pyramidal cells and interneurons in acutely prepared hippocampal slices from 3-to 4-wk old rats to characterize these understudied receptors. We show that glycine application to recorded pyramidal cells and interneurons elicited strychnine-sensitive chloride-mediated currents (I gly ) that did not completely desensitize in the continued presence of agonist but reached a steady state at 45-60% of the peak amplitude. Additionally, the inhibitory amino acid, taurine, which has been shown to activate GlyRs in other systems, activated GlyRs expressed by both pyramidal cells and interneurons, although with much less potency than glycine, having an EC 50 10-fold higher. To examine the potential subunit composition of hippocampal GlyRs, we tested the effect of the GABA A receptor antagonist, picrotoxin, on I gly recorded from both cell types. At low micromolar concentrations of picrotoxin (Յ100 M), which selectively block ␣ homomeric GlyRs, I gly was partially attenuated in both cell types, indicating that ␣ homomeric receptors are expressed by pyramidal cells and interneurons. At picrotoxin concentrations Յ1 mM, ϳ10 -20% of the whole cell current remained, suggesting that ␣␤ heteromeric GlyRs are also expressed because this subtype of GlyR is relatively resistant to picrotoxin antagonism. Finally, we examined whether hippocampal GlyRs are modulated by zinc. Consistent with previous reports in other preparations, zinc elicited a bidirectional modulation of GlyRs, with physiological zinc concentrations (1-100 M) increasing whole cell currents and concentrations Ͼ100 M depressing them. Furthermore, the same concentration of zinc that potentiates I gly suppressed currents mediated by the N-methyl-D-aspartate subtype of the glutamate receptor. Thus we provide a pharmacological characterization of native GlyRs expressed by both major neuron types in hippocampus and show that these receptors can be activated by taurine, an amino acid that is highly concentrated in hippocampus. Furthermore, our data suggest that at least two GlyR subtypes are present in hippocampus and that GlyR-mediated currents can be potentiated by zinc at concentrations that suppress glutamate-mediated excitability.

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“…Uninfected or wild-type AcNPV infected Sf9 cells were glycine-insensitive. Thus, expression of the human GlyR ~1 subunit in insect cells generates glycine-gated chloride channels, which display a pharmacology typical of the mammalian GlyR (compare [2][3][4][5]). …”

Section: Functional Analysis'mentioning

confidence: 99%

“…The anion channel of these recombinant receptors is gated by the agonists glycine, fl-alanine or taurine; binding of these ligands is competitively inhibited by strychnine [2][3][4][5]. The recombinant receptors display a sedimentation behaviour indistinguishable from that of native GlyR [6], suggesting that a pentameric quaternary structure is preserved upon heterologous expression.…”

Section: Introductionmentioning

confidence: 99%

Baculovirus‐driven expression and purification of glycine receptor α1 homo‐oligomers

et al. 1995

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The glycine receptor is a figand-gated anion channel protein of postsynaptic membranes. We expressed a homo-oligomeric receptor composed of human al subunits in Spodoptera frugiperda cells by infection with a recombinant Autographa californica nuclear polyhedrosis virus. A substantial fraction of the recombinant receptor was incorporated as a functional channel protein into the cell's plasma membrane at expression levels 4-to 30-fold higher than in other eukaryotic heterologous expression systems or native rat spinal cord membranes, respectively. Upon detergent solubilization, the al receptor was found to exist in a predominantly monodisperse state and could be affinitypurified to near homogeneity. This preparation is a potential starting point for future crystallisation studies.Key words: Glycine receptor; Baculovirus; Affinity purification; Heterologous expression transmembrane topology characterized by an extended N-terminal extracellular domain followed by four transmembrane segments (M1-M4; see [1]).Here, we expressed al homo-oligomeric GlyR in Spodoptera frugiperda (Sf9) insect cells infected with a recombinant Autographa californica baculovirus, in which the GlyR al cDNA was placed under the control of the polyhedrin promoter. The baculovirus Sf9 cell system was previously used to overexpress the c~l GlyR [7] in order to produce preparative amounts of GlyR protein. Receptor purification described in that study involved solubilisation with digitonin/desoxycholate and resulted in a partially proteolysed protein. Here we used solubilisation of the receptor with the more economical conventional detergent Triton X-100 and affinity-purified it to a nearly homogenous and monodisperse state, which appears suitable for crystallization studies.

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Agonist pharmacology of neonatal and adult glycine receptor alpha subunits: identification of amino acid residues involved in taurine activation.

Cited by 167 publications

References 36 publications

A Novel Class of GABAA Receptor Subunit in Tissues of the Reproductive System

A Novel Class of GABAA Receptor Subunit in Tissues of the Reproductive System

Pharmacological Characterization of Glycine-Gated Chloride Currents Recorded in Rat Hippocampal Slices

Baculovirus‐driven expression and purification of glycine receptor α1 homo‐oligomers

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