Numbering of cloned P2 purinoceptors

The classification of receptors for adenosine, ATP and ADP (collectively called purinoceptors) has seen a number of developments in the past three years. The important division of receptors into two major classes 1 (1) adenosine (P 1 ) receptors and (2) P 2 purinoceptors, first suggested by Burnstock in 1978 (Ref.2), has been an abiding one that has set the stage for further subdivision of P 2 purinoceptors into P 2X and P 2Y subtypes on the basis of pharmacological properties 3 . Later, Dubyak 4 summarized the evidence that ATP worked through two different transduction mechanisms: intrinsic ion channels and G protein-coupled receptors. This information, coupled with the cloning of purinoceptors in 1993/94, led Abbracchio and Burnstock 5 to propose that purinoceptors should be classified in two families: G protein-coupled receptors termed P2Y purinoceptors, and intrinsic ion channels termed P2X purinoceptors. Developments in recent years have borne out these expectations and a revised nomenclature, essentially adopting the Abbracchio and Burnstock proposal, can now be proposed.

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“…King, who have done the field a great service by providing a ready access to the latest discoveries on P2 receptors 49 …”

Section: Box 1 Some Open Questionsmentioning

confidence: 99%

Towards a revised nomenclature for P1 and P2 receptors

Fredholm¹,

Abbracchio²,

Burnstock³

et al. 1997

Trends in Pharmacological Sciences

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355

476

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“…The percent amplitudes of ICa during ATP exposure in the presence of suramin and PPADS were 96.4±1.9% (n=4, p>0.05) and 95.7±4.6% (n=4, p>0.05) of the control, respectively. These results suggested that inhibitory action of ATP on ICa was due to the binding of ATP to P2Y1 purinoceptors (Burnstock and King, 1996). Two nonhydrolyzable analogues of guanine nucleotides, GTPgS and GDPbS, were used to test whether G-protein has a functional role in ATP-induced inhibition of ICa.…”

Section: Effects Of Extracellular Atp On Camentioning

confidence: 99%

P2Y-Purinoceptor Mediated Inhibition of L-type Ca2+ Channels in Rat Pancreatic .BETA.-Cells.

Gong

Kakei

Koriyama

et al. 2000

Cell Struct. Funct.

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ABSTRACT. We used the patch-clamp technique to study the effects of extracellular ATP on the activity of ion channels recorded in rat pancreatic b-cells. In cell-attached membrane patches, action currents induced by 8.3 mM glucose were inhibited by 0.1 mM ATP, 0.1 mM ADP or 15 mM ADPbS but not by 0.1 mM AMP or 0.1 mM adenosine. In perforated membrane patches, action potentials were measured in current clamp, induced by 8.3 mM glucose, and were also inhibited by 0.1 mM ATP with a modest hyperpolarization to -43 mV. In whole-cell clamp experiments, ATP dose-dependently decreased the amplitudes of L-type Ca 2+ channel currents (ICa) to 56.7±4.0% (p<0.001) of the control, but did not influence ATP-sensitive K + channel currents observed in the presence of 0.1 mM ATP and 0.1mM ADP in the pipette. Agonists of P2Y purinoceptors, 2-methylthio ATP (0.1 mM) or ADPbS (15 mM) mimicked the inhibitory effect of ATP on ICa, but PPADS (0.1 mM) and suramin (0.2 mM), antagonists of P2 purinoceptors, counteracted this effect. When we used 0.1 mM GTPgS in the pipette solution, ATP irreversibly reduced ICa to 58.4±6.6% of the control (p<0.001). In contrast, no inhibitory effect of ATP was observed when 0.2 mM GDPbS was used in the pipette solution. The use of either 20 mM BAPTA instead of 10 mM EGTA, or 0.1 mM compound 48/80, a blocker of phospholipase C (PLC), in the pipette solution abolished the inhibitory effect of ATP on ICa, but 1 mM staurosporine, a blocker of protein kinase C (PKC), did not. When the b-cells were pretreated with 0.4 mM thapsigargin, an inhibitor of the endoplasmic reticulum (ER) Ca 2+ pump, ATP lost the inhibitory effect on ICa. These results suggest that extracellular ATP inhibits action potentials by Ca 2+ -induced ICa inhibition in which an increase in cytosolic Ca 2+ released from thapsigargin-sensitive store sites was brought about by a P2Y purinoceptor-coupled G-protein, PI-PLC and IP3 pathway.

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“…Such e ects of ATP are mediated through di erent types of receptors located on the surface of cells, consisting of two families of P2 receptors that are widely distributed among mammalian cells: P2X receptors are ligand-gated non-selective cation channels; while P2Y receptors are G protein-coupled membrane receptors [1,5,6]. So far, seven subtypes of P2X receptors and nine subtypes of P2Y receptors have been identi®ed [1,9,17,31].…”

Section: Introductionmentioning

confidence: 99%

Age‐related changes in the localization of P2X (nucleotide) receptors in the rat adrenal gland

Afework¹,

Burnstock

2000

Intl J of Devlp Neuroscience

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Observation of the changes in the occurrence and distribution of nucleotide (P2X) receptors in the adrenal gland during development and ageing, and correlation with the changes in adrenal status at similar stages may give morphological insights into the functions of purine nucleotides in the gland. Age-related changes in the localization of all seven subtypes of the P2X receptor in the adrenal gland of rat were therefore investigated immunohistochemically. In the adrenal glands of prenatal rats, immunoreactivity to P2X receptor subtypes was not observed. In glands of the postnatal rat at the developmental stages studied, only immunoreactivity for the P2X 5 receptor subtype was observed. A small number of faintly P2X 5 -immunoreactive chroma n cells were found in the adrenal glands of 1-day-old rats; the frequency of localization and intensity of staining of immunoreactive cells had increased by day 4 and was further increased at day 7. P2X 5 immunoreactivity was not observed in the adrenal glands from 14-and 21-day-old rats. At 8 weeks of age, immunoreactivity with a speci®c distribution for each of the seven receptor subtypes was observed. Except for the P2X 4 receptor, adrenal glands at 24 months showed a similar pattern of immunoreactivity for the receptor subtypes as that observed at 8 weeks. Immunoreactivity for P2X 4 was ®rst observed in the adrenal cortical cells of the zona reticularis at 8 weeks, but was absent in 24-month-old rats. However, several P2X 4 -immunoreactive chroma n cells appeared at 24 months. Such immunoreactive cells were not seen in rats of any of the other ages studied. It was concluded that the greater expression of P2X 5 receptor at an early developmental stage and of P2X 4 in ageing might re¯ect functional roles for purines in cellular proliferation and/or di erentiation, and in cellular degeneration, respectively, in adrenal glands of rat. 7

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Numbering of cloned P2 purinoceptors

Cited by 152 publications

References 30 publications

Towards a revised nomenclature for P1 and P2 receptors

Towards a revised nomenclature for P1 and P2 receptors

P2Y-Purinoceptor Mediated Inhibition of L-type Ca2+ Channels in Rat Pancreatic .BETA.-Cells.

Age‐related changes in the localization of P2X (nucleotide) receptors in the rat adrenal gland

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