Regulation of adenosine 5′-triphosphate (ATP)-gated P2X4 receptors on tracheal smooth muscle cells

Miyuki Nagaoka, Masayuki Nara, Tsutomu Tamada, Hiroaki Kume, Tetsuya Oguma, Toshiaki Kikuchi, Jamal Zaini, Takuya Moriya, Masakazu Ichinose, Gen Tamura, Toshio Hattori

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


We examined the effects of extracellular adenosine 5′-triphosphate (ATP) on single airway smooth muscle (ASM) cells from porcine trachea using a patch-clamp technique. ATP induced a sustained inward current. Phospholipase C inhibitor U-73122 failed to inhibit the current, suggesting the involvement of P2X receptor. A specific effecter of P2X4, ivermectin, augmented the current indicating the existence of P2X4 receptors. Immunohistochemistry and reverse transcription/polymerase chain reaction analysis and Western blot analysis also showed the distribution of the P2X4 receptors. The inward current was reduced by SKF-96365, an inhibitor of both voltage-dependent Ca2+ channels (VDCCs) and voltage-independent Ca2+ channels, although a VDCC antagonist, verapamil, did not affect the current. SKF-96365 caused complete suppression of both the increase in the intracellular Ca2+ concentration and the contraction of ASM cells induced by ATP. Our results demonstrate that P2X4 receptors exist on ASM and that the receptors are responsible for Ca2+ influx. These findings suggest that the Ca2+ influx regulated by P2X4 receptors plays an important role in ASM contraction by a pathway distinct from VDCC.

Original languageEnglish
Pages (from-to)61-67
Number of pages7
JournalRespiratory Physiology and Neurobiology
Issue number1
Publication statusPublished - 2009 Mar 31


  • Airway smooth muscle
  • Ivermectin
  • Purinergic receptor


Dive into the research topics of 'Regulation of adenosine 5′-triphosphate (ATP)-gated P2X4 receptors on tracheal smooth muscle cells'. Together they form a unique fingerprint.

Cite this