Amiloride attenuates glycine-induced currents in cultured neurons of rat inferior colliculus

Tang, Zheng-Quan; Lu, Yungang; Zhou, Ke-Qing; Xu, Tian‐Le; Chen, Lin

doi:10.1016/j.bbrc.2006.09.110

Cited by 10 publications

(10 citation statements)

References 29 publications

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“…Inferior colliculus neurons of newborn Wistar rats (postnatal Day 0 or 1) were isolated as described previously 18 . Briefly, the inferior colliculus was collected from the whole brain in chilled Hank’s buffered salt solution.…”

Section: Methodsmentioning

confidence: 99%

Inhibitory effects of amiloride on the current mediated by native GABA_A receptors in cultured neurons of rat inferior colliculus

Liu

Zhang

Tang

et al. 2010

Clin Exp Pharma Physio

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1. The diuretic amiloride is known to modulate the activity of several types of ion channels and membrane receptors in addition to its inhibitory effects on many ion transport systems. However, the effects of amiloride on some important ion channels and receptors, such as GABA(A) receptors, in the central nervous system have not been characterized. 2. In the present study, we investigated the functional action of amiloride on native GABA(A) receptors in cultured neurons of rat inferior colliculus using whole-cell patch-clamp recordings. 3. Amiloride reversibly inhibited the amplitude of the GABA-induced current (I(GABA)) in a concentration-dependent manner (IC(50) 454 +/- 24 micromol/L) under conditions of voltage-clamp with a holding potential at -60 mV. The inhibition depended on drug application mode and was independent of membrane potential. Amiloride did not change the reversal potential of I(GABA). Moreover, amiloride induced a parallel right-ward shift in the concentration-response curve for I(GABA) without altering the maximal value and Hill coefficient. 4. The present study shows that amiloride competitively inhibits the current mediated by native GABA(A) receptors in the brain region, probably via a direct action on GABA-binding sites on the receptor. The findings suggest that the functional actions of amiloride on GABA(A) receptors may result in possible side-effects on the central nervous system in the case of direct application of this drug into the cerebrospinal fluid for treatment of diseases such as brain tumours.

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Section: Methodsmentioning

confidence: 99%

Inhibitory effects of amiloride on the current mediated by native GABA_A receptors in cultured neurons of rat inferior colliculus

Liu

Zhang

Tang

et al. 2010

Clin Exp Pharma Physio

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“…The neurones used for cell culture were dissociated from the inferior colliculus (IC) of Wistar rats (postnatal day 0) as previously described (Tang et al. , 2006).…”

Section: Methodsmentioning

confidence: 99%

“…The neurones used for cell culture were dissociated from the inferior colliculus (IC) of Wistar rats (postnatal day 0) as previously described (Tang et al, 2006). In brief, the IC was dissected from the brainstem under a dissection microscope and then dissociated by 0.25% trypsin and plated (1.5 ¥ 10 6 cell·mL -1 ) on poly-L-lysine (Sigma, St Louis, MO, USA)-coated cover glasses.…”

Section: Cell Culturementioning

confidence: 99%

Salicylate, an aspirin metabolite, specifically inhibits the current mediated by glycine receptors containing α1‐subunits

et al. 2009

British J Pharmacology

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Background and purpose: Aspirin or its metabolite sodium salicylate is widely prescribed and has many side effects. Previous studies suggest that targeting neuronal receptors/ion channels is one of the pathways by which salicylate causes side effects in the nervous system. The present study aimed to investigate the functional action of salicylate on glycine receptors at a molecular level. Experimental approach: Whole-cell patch-clamp and site-directed mutagenesis were deployed to examine the effects of salicylate on the currents mediated by native glycine receptors in cultured neurones of rat inferior colliculus and by glycine receptors expressed in HEK293T cells. Key results: Salicylate effectively inhibited the maximal current mediated by native glycine receptors without altering the EC50 and the Hill coefficient, demonstrating a non-competitive action of salicylate. Only when applied simultaneously with glycine and extracellularly, could salicylate produce this antagonism. In HEK293T cells transfected with either a1-, a2-, a3-, a1b-, a2b-or a3b-glycine receptors, salicylate only inhibited the current mediated by those receptors that contained the a1-subunit. A single site mutation of I240V in the a1-subunit abolished inhibition by salicylate. Conclusions and implications:Salicylate is a non-competitive antagonist specifically on glycine receptors containing a1-subunits. This action critically involves the isoleucine-240 in the first transmembrane segment of the a1-subunit. Our findings may increase our understanding of the receptors involved in the side effects of salicylate on the central nervous system, such as seizures and tinnitus.

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“…The inhibitory effect of the diuretic amiloride, an acid-sensing ion channel antagonist, on GABA-A receptors was first reported in the frog sensory neurons (Inomata et al, 1988), and subsequent studies focused on amiloride in GABA-A abg receptors showed that the guanidine compound competitively antagonized the receptors with a 10-fold increased potency in GABA-A a6-containing receptors (Fisher, 2002). In the inhibitory glycine receptor, amiloride exhibited competitive antagonism in receptors expressed in rat spinal neurons and inferior colliculus (Li et al, 2003a,b;Tang et al, 2006). Furthermore, a recent report outlined the antagonistic effects of the guanidine compound 2-guanidine-4-methylquinazoline (GMQ) on the heteromeric GABA-A abg receptors (Xiao et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Amiloride and GMQ Allosteric Modulation of the GABA-A ρ1 Receptor: Influences of the Intersubunit Site

Snell¹,

Gonzales²

2015

J Pharmacol Exp Ther

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Amiloride, a diuretic used in the treatment of hypertension and congestive heart failure, and 2-guanidine-4-methylquinazoline (GMQ) are guanidine compounds that modulate acid-sensing ion channels. Both compounds have demonstrated affinity for a variety of membrane proteins, including members of the Cysloop family of ligand-gated ion channels, such as the heteromeric GABA-A abg receptors. The actions of these guanidine compounds on the homomeric GABA-A r1 receptor remains unclear, especially in light of how many GABA-A abg receptor modulators have different effects in the GABA-A r1 receptors. We sought to characterize the influence of amiloride and GMQ on the human GABA-A r1 receptors using whole-cell patch-clamp electrophysiology. The diuretic amiloride potentiated the human GABA-A r1 GABA-mediated current, whereas GMQ antagonized the receptor. Furthermore, a GABA-A second transmembrane domain site, the intersubunit site, responsible for allosteric modulation in the heteromeric GABA-A receptors mediated amiloride's positive allosteric actions. In contrast, the mutation did not remove GMQ antagonism but only changed the guanidine compound's potency within the human GABA-A r1 receptor. Through modeling and introduction of point mutations, we propose that the GABA-A r1 intersubunit site plays a role in mediating the allosteric effects of amiloride and GMQ.

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Amiloride attenuates glycine-induced currents in cultured neurons of rat inferior colliculus

Cited by 10 publications

References 29 publications

Inhibitory effects of amiloride on the current mediated by native GABA_A receptors in cultured neurons of rat inferior colliculus

Inhibitory effects of amiloride on the current mediated by native GABA_A receptors in cultured neurons of rat inferior colliculus

Salicylate, an aspirin metabolite, specifically inhibits the current mediated by glycine receptors containing α1‐subunits

Amiloride and GMQ Allosteric Modulation of the GABA-A ρ1 Receptor: Influences of the Intersubunit Site

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Amiloride attenuates glycine-induced currents in cultured neurons of rat inferior colliculus

Cited by 10 publications

References 29 publications

Inhibitory effects of amiloride on the current mediated by native GABAA receptors in cultured neurons of rat inferior colliculus

Inhibitory effects of amiloride on the current mediated by native GABAA receptors in cultured neurons of rat inferior colliculus

Salicylate, an aspirin metabolite, specifically inhibits the current mediated by glycine receptors containing α1‐subunits

Amiloride and GMQ Allosteric Modulation of the GABA-A ρ1 Receptor: Influences of the Intersubunit Site

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Inhibitory effects of amiloride on the current mediated by native GABA_A receptors in cultured neurons of rat inferior colliculus

Inhibitory effects of amiloride on the current mediated by native GABA_A receptors in cultured neurons of rat inferior colliculus