Masahiro Ikeda1. 1. Department of Veterinary Pharmacology, Faculty of Agriculture, University of Miyazaki, Gakuenkibanadai-nishi 1-1, Miyazaki 889-2192, Japan.
Abstract
INTRODUCTION: Although accumulating evidence within the past 5 years strongly supports the importance of platelet P2X(1) receptors in hemostasis and thrombosis, P2X(1) receptors of platelet and/or its progenitor cell, megakaryocyte, have not been fully characterized. The aim of this study was to electrophysiologically and pharmacologically characterize the functional P2X(1) receptors on mouse megakaryocytes. MATERIALS AND METHODS: The currents in response to nucleotides were examined using the patch-clamp whole-cell recording. RESULTS: The agonist profile of megakaryocyte P2X(1) receptors was ATP>alpha,beta-methylene ATP>beta,gamma-methylene ATP. The P2X(1) receptors exhibited substantial monovalent as well as divalent cation permeability and the ratios of Na(+) to Cs(+) and Ca(2+) to Cs(+) permeability were 1 and 2.5, respectively. P2X receptor antagonists except suramin significantly inhibited the P2X(1) responses with an IC(50) values of 0.4 microM for pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS), 0.3 microM for 2',3'-O-(2,4,6-trinitophenyl)-adenosine 5'-triphosphate (TNP-ATP), 20 microM for reactive blue 2 (RB2), or 160 microM for 8,8'-(carbonylbis(imino-3,1-phenylene carbonylimino)bis(1,3,5-naphthalenetrisulfonic acid) (NF023), respectively. Suramin had no significant effect on the P2X(1) responses. In rat megakaryocytes, suramin similarly had no significant effect on the P2X(1) responses, but abolished the P2Y receptor-mediated responses, indicating that the suramin was active under present experimental condition. CONCLUSIONS: These results provide the basic properties of mouse megakaryocyte P2X(1) receptors and would be helpful to examine the P2 receptor signaling in platelets and megakaryocytes.
INTRODUCTION: Although accumulating evidence within the past 5 years strongly supports the importance of platelet P2X(1) receptors in hemostasis and thrombosis, P2X(1) receptors of platelet and/or its progenitor cell, megakaryocyte, have not been fully characterized. The aim of this study was to electrophysiologically and pharmacologically characterize the functional P2X(1) receptors on mouse megakaryocytes. MATERIALS AND METHODS: The currents in response to nucleotides were examined using the patch-clamp whole-cell recording. RESULTS: The agonist profile of megakaryocyte P2X(1) receptors was ATP>alpha,beta-methylene ATP>beta,gamma-methylene ATP. The P2X(1) receptors exhibited substantial monovalent as well as divalent cation permeability and the ratios of Na(+) to Cs(+) and Ca(2+) to Cs(+) permeability were 1 and 2.5, respectively. P2X receptor antagonists except suramin significantly inhibited the P2X(1) responses with an IC(50) values of 0.4 microM for pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS), 0.3 microM for 2',3'-O-(2,4,6-trinitophenyl)-adenosine 5'-triphosphate (TNP-ATP), 20 microM for reactive blue 2 (RB2), or 160 microM for 8,8'-(carbonylbis(imino-3,1-phenylene carbonylimino)bis(1,3,5-naphthalenetrisulfonic acid) (NF023), respectively. Suramin had no significant effect on the P2X(1) responses. In rat megakaryocytes, suramin similarly had no significant effect on the P2X(1) responses, but abolished the P2Y receptor-mediated responses, indicating that the suramin was active under present experimental condition. CONCLUSIONS: These results provide the basic properties of mouse megakaryocyte P2X(1) receptors and would be helpful to examine the P2 receptor signaling in platelets and megakaryocytes.
Authors: Craig N Morrell; Henry Sun; Masahiro Ikeda; Jean-Claude Beique; Anne Marie Swaim; Emily Mason; Tanika V Martin; Laura E Thompson; Oguz Gozen; David Ampagoomian; Rolf Sprengel; Jeffrey Rothstein; Nauder Faraday; Richard Huganir; Charles J Lowenstein Journal: J Exp Med Date: 2008-02-18 Impact factor: 14.307
Authors: Tania Kamal; Taryn N Green; James I Hearn; Emma C Josefsson; Marie-Christine Morel-Kopp; Christopher M Ward; Matthew J During; Maggie L Kalev-Zylinska Journal: Res Pract Thromb Haemost Date: 2017-12-14