Purinergic receptors coupled to intracellular Ca2+ signals and exocytosis in rat prostate neuroendocrine cells

Jun Hee Kim, Joo Hyun Nam, Mean Hwan Kim, Duk Su Koh, So Jung Choi, Soo Jeong Kim, Ji Eun Lee, Kyeong Min Min, Dae Yong Uhm, Sung Joon Kim

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Rat prostate neuroendocrine cells (RPNECs) display a variety of ion channels and exhibit α-adrenergic regulation of cytosolic Ca2+ concentration ([Ca2+]c). In this study, purinergic regulation of [Ca2+]c and exocytosis was investigated in freshly isolated single RPNECs showing chromogranin A immunoreactivity. The presence of P2X and P2Y receptors in RPNECs was verified by the transient activation of Ca2+-permeable cationic channels and the release of Ca2+ from intracellular stores by extracellular ATP, respectively. The transient inward cationic current was effectively activated by α,β-methyleneadenosine 5′-triphosphate (α,β-MeATP) and blocked by 2′,3′-O-(2,4,6-trinitrophenyl)adenosine 5′-triphosphate, suggesting the presence of a P2X1 or P2X 3 subtype. For the release of stored Ca2+, ATP and UTP were equally potent, indicating the functional expression of the P2Y2 or P2Y4 subtype. The mRNAs for P2X1 and P2Y2 were confirmed from reverse transcription-PCR analysis of RPNECs. The application of α,β-MeATP induced large and transient increases in [Ca2+]c which were not attenuated by the blockers of voltage-activated Ca2+ channels or by depleting intracellular Ca 2+ stores, but were abolished by omitting extracellular Ca 2+. The application of UTP increased [CA2+]c to 55% of the peak Δ[Ca2+]c induced by α,β-MeATP. The application of α,β-MeATP induced exocytotic responses of RPNECs as monitored by carbon fiber amperometry and capacitance measurements. To our interest, the application of UTP did not induce amperometric currents, but reduced the membrane capacitance, indicating a net endocytosis. From these results, we postulate that a sharp rise in [Ca 2+]c by the P2X-mediated Ca2+ influx is required for exocytosis, whereas the relatively slow release of stored Ca 2+ induces endocytosis in RPNECs.

Original languageEnglish (US)
Pages (from-to)27345-27356
Number of pages12
JournalJournal of Biological Chemistry
Volume279
Issue number26
DOIs
StatePublished - Jun 25 2004
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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