Research Article| Volume 234, 102830, September 2021

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P2X3 receptors participate in purinergic inhibition of gastrointestinal smooth muscle


      • Inhibitory nerves control the contractility of gastrointestinal smooth muscle.
      • ATP and β-NAD are released from inhibitory nerves and target P2Y1 receptors.
      • A synthetic nucleotide α,β-meATP mimics ATP and β-NAD, but cannot directly activate P2Y1 receptors.
      • Instead, α,β-meATP activates P2X3 receptors on inhibitory nerves.
      • P2X3 receptors are Ca2+-permeable ion channels which can release neurotransmitters.


      The ATP analogue α,β-meATP is a potent relaxant of gastrointestinal smooth muscle, but its molecular target is uncertain inside the gut. α,β-meATP relaxed the carbachol-precontracted guinea-pig taenia coli in a concentration-dependent manner (EC50, 2.0 ± 0.1 μM). A luciferase-based assay confirmed that α,β-meATP solutions were minimally contaminated with ATP. α,β-meATP-evoked relaxations were inhibited by the competitive P2Y1 antagonist MRS2179 (pA2 = 5.36), but also by the competitive P2X3 antagonist, A-317491 (pA2 = 5.51). When MRS2179 and A-317491 were applied together, residual α,β-meATP responses converted from brief to prolonged relaxations. Sodium nitroprusside (a nitric oxide donor) also caused prolonged relaxations. Immunohistochemistry revealed that P2X3 receptors were present in myenteric ganglion cells and their varicose nerve terminals. The amplitude of α,β-meATP responses was not inhibited by TTX (NaV channel blocker) and ωCgTx (N-type CaV channel blocker). However, responses to α,β-meATP were inhibited by TEA (non-selective K+-channel blocker), indicating that relaxations involved opening K+-channels. The findings of this study are consistent with the conclusion that α,β-meATP stimulates Ca2+-permeable P2X3 receptors on varicose nerve terminals to release inhibitory nucleotides: 1) ATP and β-NAD release results in P2Y1-mediated brief relaxations; 2) another released transmitter (possibly NO) results in prolonged relaxations. Prejunctional P2X3 receptors represent a purinergic feed-forward mechanism to augment the action of inhibitory nerves on gut motility. This positive feed-forward mechanism may counter-balance the known negative feedback mechanism caused by adenosine and prejunctional A1 receptors on inhibitory motor nerves.

      Graphical abstract



      A1 (adenosine receptor (Type 1)), A2B (adenosine receptor (Type 2B)), A-317491 (competitive P2X3 antagonist), [3H]-ACh (tritiated acetylcholine), ATP (adenosine 5′-triphosphate), α,β-meATP (alpha,beta-methylene-ATP), EC50 (estimate of agonist potency), ICC (interstitial cells of Cajal), IJP (inhibitory junction potential), MRS2179 (competitive P2Y1 antagonist), [3H]-NA (tritiated noradrenaline), β-NAD (beta-nicotinamide adenine dinucleotide), NANC (nonadrenergic, noncholinergic), nH (Hill co-efficient (slope of C/R curve)), NO (nitric oxide), pA2 (estimate of antagonist efficacy), PDGFR (platelet-derived growth factor receptor), RLU (relative light units), SK channels (small-conductance Ca2+-activated K+-channels), SMCs (smooth muscle cells), SNP (sodium nitroprusside), TEA (tetraethylammonium chloride), TTX (tetrodotoxin), ωCgTx (omega conotoxin GV1A)
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        • Baker S.A.
        • Hennig G.W.
        • Ward S.M.
        • Sanders K.M.
        Temporal sequence of activation of cells involved in purinergic neurotransmission in the colon.
        J. Physiol. 2015; 593: 1945-1963
        • Barajas-López C.
        • Huizinga J.D.
        • Collins S.M.
        • Gerzanich V.
        • Espinosa-Luna R.
        • Peres A.L.
        P2X purinoceptors of myenteric neurones from the guinea-pig ileum and their unusual pharmacological properties.
        Br. J. Pharmacol. 1996; 119: 1541-1548
        • Barthó L.
        • Lénárd Jr., L.
        • Szigeti R.
        Nitric oxide and ATP co-mediate the NANC relaxant response in the guinea-pig taenia caeci.
        Naunyn Schmiedeberg’s Arch. Pharmacol. 1998; 358: 496-499
        • Bauer V.
        • Kuriyama H.
        The nature of non-cholinergic, non-adrenergic transmission in longitudinal and circular muscles of the guinea-pig ileum.
        J. Physiol. 1982; 332: 375-391
        • Bennett M.R.
        • Rogers D.C.
        A study of the innervation of the taenia coli.
        J. Cell Biol. 1967; 33: 573-596
        • Bennett M.R.
        • Burnstock G.
        • Holman M.
        Transmission from intramural inhibitory nerves to the smooth muscle of the guinea-pig taenia coli.
        J. Physiol. 1966; 182: 541-558
        • Beyder A.
        • Farrugia G.
        Targeting ion channels for the treatment of gastrointestinal motility disorders.
        Ther. Adv. Gastroenterol. 2012; 5: 5-21
        • Boeckxstaens G.E.
        • Pelckmans P.A.
        • Bult H.
        • De Man J.G.
        • Herman A.G.
        • van Maercke Y.M.
        Evidence for nitric oxide as mediator of non-adrenergic non-cholinergic relaxations induced by ATP and GABA in the canine gut.
        Br. J. Pharmacol. 1991; 102: 434-438
        • Boyer J.L.
        • Mohanram A.
        • Camaioni E.
        • Jacobson K.A.
        • Harden T.K.
        Competitive and selective antagonism of P2Y1 receptors by N6-methyl 2′-deoxyadenosine 3′,5′-bisphosphate.
        Br. J. Pharmacol. 1998; 124: 1-3
        • Bridgewater M.
        • Cunnane T.C.
        • Brading A.F.
        Characteristic features of inhibitory junction potentials evoked by single stimuli in the guinea-pig isolated taenia caeci.
        J. Physiol. 1995; 485: 145-155
        • Brown S.G.
        • King B.F.
        • Kim Y.C.
        • Jang S.Y.
        • Burnstock G.
        • Jacobson K.A.
        Activity of novel adenine nucleotide derivatives as agonists and antagonists at recombinant rat P2X receptors.
        Drug Dev. Res. 2000; 49: 253-259
        • Buell G.
        • Collo G.
        • Rassendren F.
        P2X receptors: an emerging channel family.
        Eur. J. Neurosci. 1996; 8: 2221-2228
        • Bültmann R.
        • Dudeck O.
        • Starke K.
        Evaluation of P2-purinoceptor antagonists at two relaxation-mediating P2-purinoceptors in guinea-pig taenia coli.
        Naunyn Schmiedeberg’s Arch. Pharmacol. 1996; 353: 445-451
        • Burnstock G.
        The journey to establish purinergic signalling in the gut.
        Neurogastroenterol. Motil. 2008; 20: 8-19
        • Burnstock G.
        Purinergic signalling in the gastrointestinal tract and related organs in health and disease.
        Purinergic Signal. 2014; 10: 3-50
        • Burnstock G.
        • Kennedy C.
        Is there a basis for distinguishing two types of P2-purinoceptor?.
        Gen. Pharmacol. 1985; 16: 433-440
        • Burnstock G.
        • Campbell G.
        • Satchell D.
        • Smythe A.
        Evidence that adenosine triphosphate or a related nucleotide is the transmitter substance released by non-adrenergic inhibitory nerves in the gut.
        Br. J. Pharmacol. 1970; 40: 668-688
        • Chen C.C.
        • Akopian A.N.
        • Sivilotti L.
        • Colquhoun D.
        • Burnstock G.
        • Wood J.N.
        A P2X purinoceptor expressed by a subset of sensory neurons.
        Nature. 1995; 377: 428-431
        • Cusack N.J.
        • Hourani S.M.O.
        • Loizou G.D.
        • Welford L.A.
        Pharmacological effects of isopolar phosphonate analogues of ATP on P2-purinoceptors in guinea-pig taenia coli and urinary bladder.
        Br. J. Pharmacol. 1987; 90: 791-795
        • De Man J.G.
        • De Winter B.Y.
        • Seerden T.C.
        • De Schepper H.U.
        • Herman A.G.
        • Pelckmans P.A.
        Functional evidence that ATP or a related purine is an inhibitory NANC neurotransmitter in the mouse jejunum: study on the identity of P2X and P2Y purinoceptors involved.
        Br. J. Pharmacol. 2003; 140: 1108-1116
        • Den Hertog A.
        • Pielkenrood J.
        • Van den Akker J.
        Effector mechanisms for alpha,beta-methylene ATP and ATP derivatives in guinea-pig taenia caeci.
        Eur. J. Pharmacol. 1985; 110: 95-101
        • Dreisig K.
        • Kornum B.R.
        A critical look at the function of the P2Y11 receptor.
        Purinergic Signal. 2016; 12: 427-437
        • Dudeck O.
        • Bültmann R.
        • Starke K.
        Two relaxation-mediating P2-purinoceptors in guinea-pig taenia coli.
        Naunyn Schmiedeberg’s Arch. Pharmacol. 1995; 351: 107-110
        • Dunn P.M.
        • Zhong Y.
        • Burnstock G.
        P2X receptors in peripheral neurons.
        Prog. Neurobiol. 2001; 65: 107-134
        • Facer P.
        • Knowles C.H.
        • Tam P.K.
        • Ford A.P.
        • Dyer N.
        • Baecker P.A.
        • Anand P.
        Novel capsaicin (VR1) and purinergic (P2X3) receptors in Hirschsprung’s intestine.
        J. Pediatr. Surg. 2001; 36: 1679-1684
        • Filtz T.M.
        • Li Q.
        • Boyer J.L.
        • Nicholas R.A.
        • Harden T.K.
        Expression of a cloned P2Y purinergic receptor that couples to phospholipase C.
        Mol. Pharmacol. 1994; 46: 8-14
        • Gallego D.
        • Gil V.
        • Martínez-Cutillas M.
        • Mañé N.
        • Martín M.T.
        • Jiménez M.
        Purinergic neuromuscular transmission is absent in the colon of P2Y1 knocked out mice.
        J. Physiol. 2012; 590: 1943-1956
        • Gao N.
        • Hu H.Z.
        • Zhu M.X.
        • Fang X.
        • Liu S.
        • Gao C.
        • Wood J.D.
        The P2Y purinergic receptor expressed by enteric neurones in guinea-pig intestine.
        Neurogastroenterol. Motil. 2006; 18: 316-323
        • Goyal R.K.
        • Sullivan M.P.
        • Chaudhury A.
        Progress in understanding of inhibitory purinergic neuromuscular transmission in the gut.
        Neurogastroenterol. Motil. 2013; 25: 203-207
        • Henderson D.J.
        • Elliot D.G.
        • Smith G.M.
        • Webb T.E.
        • Dainty I.A.
        Cloning and characterisation of a bovine P2Y receptor.
        Biochem. Biophys. Res. Commun. 1995; 212: 648-656
        • Hwang S.J.
        • Blair P.J.
        • Durnin L.
        • Mutafova-Yambolieva V.
        • Sanders K.M.
        • Ward S.M.
        P2Y1 purinoreceptors are fundamental to inhibitory motor control of murine colonic excitability and transit.
        J. Physiol. 2012; 590: 1957-1972
        • Illes P.
        • Müller C.E.
        • Jacobson K.A.
        • Grutter T.
        • Nicke A.
        • Fountain S.J.
        • Kennedy C.
        • Schmalzing G.
        • Jarvis M.
        • Stojilkovic S.S.
        • King B.F.
        • Di Virgilio F.
        Update of P2X receptor properties and their pharmacology; IUPHAR Review 30.
        Br. J. Pharmacol. 2021; 178: 489-514
        • Jarvis M.F.
        • Khakh B.S.
        ATP-gated P2X cation-channels.
        Neuropharmacol. 2009; 56: 208-215
        • Jarvis M.F.
        • Burgard E.C.
        • McGaraughty S.
        • Honore P.
        • Lynch K.
        • Brennan T.J.
        • Subieta A.
        • Van Biesen T.
        • Cartmell J.
        • Bianchi B.
        • Niforatos W.
        • Kage K.
        • Yu H.
        • Mikusa J.
        • Wismer C.T.
        • Zhu C.Z.
        • Chu K.
        • Lee C.H.
        • Stewart A.O.
        • Polakowski J.
        • Cox B.F.
        • Kowaluk E.
        • Williams M.
        • Sullivan J.
        • Faltynek C.
        A-317491, a novel potent and selective non-nucleotide antagonist of P2X3 and P2X2/3 receptors, reduces chronic inflammatory and neuropathic pain in the rat.
        Proc. Natl. Acad. Sci. U. S. A. 2002; 99: 17179-17184
        • Kennedy C.
        ATP as a cotransmitter in the autonomic nervous system.
        Auton. Neurosci. 2015; 191: 2-15
        • Kennedy C.
        P2Y11 receptors: properties, distribution and functions.
        Adv. Exp. Med. Biol. 2017; 1051: 107-122
        • Khakh B.S.
        • Burnstock G.
        • PPA Humphrey
        • Kennedy C.
        • King B.F.
        • North R.A.
        • Séguéla P.
        • Voigt M.
        International Union of Pharmacology. XXIV. Current status of the nomenclature and properties of P2X receptors and their subunits.
        Pharmacol. Rev. 2001; 51: 107-118
        • King B.F.
        Prejunctional autoinhibition of purinergic transmission in circular muscle of guinea-pig ileum; a mechanism distinct from P1-purinoceptor activation.
        J. Auton. Nerv. Syst. 1994; 48: 55-63
        • King B.F.
        Purinergic signalling in the enteric nervous system (an overview of current perspectives).
        Auton. Neurosci. 2015; 191: 141-147
        • King B.F.
        Burnstock and the legacy of the inhibitory junction potential and P2Y1 receptors.
        Purinergic Signal. 2021; 17: 25-31
        • King B.F.
        • Goodey G.C.
        Evaluation of PD20 Lumitester for measurement of extracellular ATP.
        Purinergic Signal. 2012; 8: 792
        • King B.F.
        • Townsend-Nicholson A.
        Involvement of P2Y1 and P2Y11 purinoceptors in parasympathetic inhibition of colonic smooth muscle.
        J. Pharmacol. Exp. Ther. 2008; 324: 1055-1063
        • Klemm M.F.
        • Lang R.J.
        Distribution of Ca2+-activated K+ channel (SK2 and SK3) immunoreactivity in intestinal smooth muscles of the guinea-pig.
        Clin. Exp. Pharmacol. Physiol. 2002; 29: 18-25
        • Léon C.
        • Hechler B.
        • Vial C.
        • Leray C.
        • Cazenave J.P.
        • Gachet C.
        The P2Y1 receptor is an ADP receptor antagonized by ATP and expressed in platelets and megakaryoblastic cells.
        FEBS Lett. 1997; 403: 26-30
        • Lewis C.
        • Neidhart S.
        • Holy C.
        • North R.A.
        • Buell G.
        • Surprenant A.
        Co-expression of P2X2 and P2X3 receptor subunits can account for ATP-gated currents in sensory neurons.
        Nature. 1995; 377: 432-435
        • MacKenzie A.B.
        • Surprenant A.
        • North R.A.
        Functional and molecular diversity of purinergic ion channel receptors.
        Ann. N. Y. Acad. Sci. 1999; 868: 716-729
        • Mader F.
        • Krause L.
        • Tokay T.
        • Hakenberg O.W.
        • Köhling R.
        • Kirschstein T.
        P2Y receptor-mediated transient relaxation of rat longitudinal ileum preparations involves phospholipase C activation, intracellular Ca2+ release and SK channel activation.
        Acta Pharmacol. Sin. 2016; 37: 617-628
        • Maguire M.H.
        • Satchell D.G.
        The contribution of adenosine to the inhibitory actions of adenine nucleotides on the guinea-pig taenia coli: studies with phosphate-modified adenine nucleotide analogs and dipyridamole.
        J. Pharmacol. Exp. Ther. 1979; 211: 626-631
        • Mutafova-Yambolieva V.N.
        Neuronal and extraneuronal release of ATP and NAD+ in smooth muscle.
        IUBMB Life. 2012; 64: 817-824
        • North R.A.
        Molecular physiology of P2X receptors.
        Physiol. Rev. 2002; 82: 1013-1067
        • Piper A.S.
        • Hollingsworth M.
        The purinoceptors of the guinea-pig isolated taenia caeci.
        Eur. J. Pharmacol. 1995; 280: 125-134
        • Poole D.P.
        • Castelucci P.
        • Robbins H.L.
        • Chiocchetti R.
        • Furness J.B.
        The distribution of P2X3 purine receptor subunits in the guinea pig enteric nervous system.
        Auton. Neurosci. 2002; 101: 39-47
        • Prentice D.J.
        • Hourani S.M.
        Adenosine analogues relax guinea-pig taenia caeci via an adenosine A2B receptor and a xanthine-resistant site.
        Eur. J. Pharmacol. 1997; 323: 103-106
        • Sanders K.M.
        Enteric inhibitory neurotransmission, starting down under.
        Adv. Exp. Med. Biol. 2016; 891: 21-29
        • Sanders K.M.
        Discovery and Nature of the ATP-Like Transmitter in the Gut.
        2021 (This issue, details to be added by editor)
        • Sanders K.M.
        • Koh S.D.
        • Ro S.
        • Ward S.M.
        Regulation of gastrointestinal motility — insights from smooth muscle biology.
        Nat. Rev. Gastroenterol. Hepatol. 2012; 9: 633-645
        • Sanders K.M.
        • Ward S.M.
        • Koh S.D.
        Interstitial cells: regulators of smooth muscle function.
        Physiol. Rev. 2014; 94: 859-907
        • Satchell D.G.
        • Maguire M.H.
        Inhibitory effects of adenine nucleotide analogs on the isolated guinea-pig taenia coli.
        J. Pharmacol. Exp. Ther. 1975; 195: 540-548
        • Schachter J.B.
        • Li Q.
        • Boyer J.L.
        • Nicholas R.A.
        • Harden T.K.
        Second messenger cascade specificity and pharmacological selectivity of the human P2Y1-purinoceptor.
        Br. J. Pharmacol. 1996; 118: 167-173
        • Selemidis S.
        • Satchell D.G.
        • Cocks T.M.
        Evidence that NO acts as a redundant NANC inhibitory neurotransmitter in the guinea-pig isolated taenia coli.
        Br. J. Pharmacol. 1997; 121: 604-611
        • Shuttleworth C.W.
        • Murphy R.
        • Furness J.B.
        Evidence that nitric oxide participates in non-adrenergic inhibitory transmission to intestinal muscle in the guinea-pig.
        Neurosci. Lett. 1991; 130: 77-80
        • Shuttleworth C.W.
        • Sweeney K.M.
        • Sanders K.M.
        Evidence that nitric oxide acts as an inhibitory neurotransmitter supplying taenia from the guinea-pig caecum.
        Br. J. Pharmacol. 1999; 127: 1495-1501
        • Silva-Ramos M.
        • Silva I.
        • Faria M.
        • Ferreirinha F.
        • Correia-de-Sá P.
        Activation of prejunctional P2X2/3 heterotrimers by ATP enhances the cholinergic tone in obstructed human urinary bladders.
        J. Pharmacol. Exp. Ther. 2020; 372: 63-72
        • Simon J.
        • Webb T.E.
        • King B.F.
        • Burnstock G.
        • Barnard E.A.
        Characterisation of a recombinant P2Y purinoceptor.
        Eur. J. Pharmacol. 1995; 291: 281-289
        • Sperlágh B.
        • Vizi E.S.
        Effect of presynaptic P2 receptor stimulation on transmitter release.
        J. Neurochem. 1991; 56: 1466-1470
        • Sperlágh B.
        • Heinrich A.
        • Csölle C.
        P2 receptor-mediated modulation of neurotransmitter release-an update.
        Purinergic Signal. 2007; 3: 269-284
        • Storr M.
        • Franck H.
        • Saur D.
        • Schusdziarra V.
        • Allescher H.D.
        Mechanisms of α,β-methylene ATP-induced inhibition in rat ileal smooth muscle: involvement of intracellular Ca2+ stores in purinergic inhibition.
        Clin. Exp. Pharmacol. Physiol. 2000; 27: 771-779
        • Tokuyama Y.
        • Hara M.
        • Jones E.M.
        • Fan Z.
        • Bell G.I.
        Cloning of rat and mouse P2Y purinoceptors.
        Biochem. Biophys. Res. Commun. 1995; 211: 211-218
        • Van Crombruggen K.
        • Van Nassauw L.
        • Timmermans J.P.
        • Lefebvre R.A.
        Inhibitory purinergic P2 receptor characterisation in rat distal colon.
        Neuropharmacology. 2007; 53: 257-271
        • van der Weyden L.
        • Adams D.J.
        • Luttrell B.M.
        • Conigrave A.D.
        • Morris M.B.
        Pharmacological characterisation of the P2Y11 receptor in stably transfected haematological cell lines.
        Mol. Cell. Biochem. 2000; 213: 75-81
        • von Kügelgen I.
        Pharmacological profiles of cloned mammalian P2Y-receptor subtypes.
        Pharmacol. Ther. 2006; 110: 415-432
        • Webb T.E.
        • Simon J.
        • Krishek B.J.
        • Bateson A.N.
        • Smart T.G.
        • King B.F.
        • Burnstock G.
        • Barnard E.A.
        Cloning and functional expression of a brain G-protein-coupled ATP receptor.
        FEBS Lett. 1993; 324: 219-225
        • Welford L.A.
        • Cusack N.J.
        • Hourani S.M.O.
        ATP analogues and the guinea-pig taenia coli: a comparison of the structure-activity relationships of ectonucleotidases with those of the P2-purinoceptor.
        Eur. J. Pharmacol. 1986; 129: 217-224
        • Windscheif U.
        • Pfaff O.
        • Ziganshin A.U.
        • Hoyle C.H.
        • Bäumert H.G.
        • Mutschler E.
        • Burnstock G.
        • Lambrecht G.
        Inhibitory action of PPADS on relaxant responses to adenine nucleotides or electrical field stimulation in guinea-pig taenia coli and rat duodenum.
        Br. J. Pharmacol. 1995; 115: 1509-1517
        • Xiang Z.
        • Burnstock G.
        P2X2 and P2X3 purinoceptors in the rat enteric nervous system.
        Histochem. Cell Biol. 2004; 121: 169-179
        • Zagorodnyuk V.P.
        • Vladimirova I.A.
        • Vovk E.V.
        • Shuba M.F.
        Studies of the inhibitory non-adrenergic neuromuscular transmission in the smooth muscle of the normal human intestine and from a case of Hirschsprung’s disease.
        J. Auton. Nerv. Syst. 1989; 26: 51-60
        • Zhang Y.
        • Lomax A.E.
        • Paterson W.G.
        P2Y1 receptors mediate apamin-sensitive and -insensitive inhibitory junction potentials in murine colonic circular smooth muscle.
        J. Pharmacol. Exp. Ther. 2010; 333: 602-611
        • Zhou X.
        • Galligan J.J.
        P2X purinoceptors in cultured myenteric neurons of guinea pig small intestine.
        J. Physiol. 1996; 496: 719-729