Role of Protease Activated Receptors in the Intracellular Calcium Dynamics of Neurons and Satellite Cells in the Rat Superior Cervical Ganglia

DOI
  • Miura Hitoshi
    Division of Dental Anesthesiology, Department of Oral and Maxillofacial Surgery, School of Dentistry, Iwate Medical University
  • Saino Tomoyuki
    Department of Anatomy (Cell Biology), Iwate Medical University
  • Sato Masahito
    Division of Dental Anesthesiology, Department of Oral and Maxillofacial Surgery, School of Dentistry, Iwate Medical University
  • Satoh Yoh-ichi
    Department of Anatomy (Cell Biology), Iwate Medical University

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Abstract

Protease-activated receptors (PARs) mediate cellular responses to various proteases in numerous cell types, including nerve cells. The issue of whether stimulation of PARs induces responses in neurons and satellite cells of sympathetic superior cervical ganglia (SCG) of rats was examined with special reference to PAR mRNA levels and to intracellular Ca2+ ([Ca2+]i) changes, since [Ca2+]i is a key factor in intracellular signaling. SCG whose essential structural integrity was maintained intact were used. RT-PCR showed that SCG expressed mRNAs encoding PAR1, 2 and 3, and PAR2 expression was the highest. Confocal microscopic analysis indicated that thrombin and trypsin induced an increase in [Ca2+]i in some neurons and many satellite cells. These proteases initially elicited a [Ca2+]i increase in satellite cells and a subsequent [Ca2+]i change in neurons. Synchronized [Ca2+]i changes in satellite cells were often observed. Neither the removal of extracellular Ca2+ nor Ca2+ channel blockers affected the trypsin-induced or PAR2-activating peptide (PAR2-AP)-induced [Ca2+]i changes in satellite cells, thus suggesting that these changes were caused by Ca2+ mobilization from an internal store, but not by Ca2+ influx. However, neither the phospholipase C inhibitor, U73122, nor the IP3 receptor antagonist, heparin, could inhibit the [Ca2+]i changes of satellite cells, whereas these reagents considerably inhibited the [Ca2+]i changes of neurons. These findings demonstrate the presence of PARs in sympathetic nervous tissue, and establish that proteases induce [Ca2+]i changes in both neurons and satellite cells via Ca2+ mobilization.

Journal

  • bioimages

    bioimages 19 (0), 17-27, 2011

    Bioimaging Society

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