Effects of protease-activated receptors (PARs) on intracellular calcium dynamics of acinar cells in rat lacrimal glands.

蛋白酶激活受体（PARs）是g蛋白偶联受体，通过蛋白水解裂解激活。在这里，泪腺腺泡细胞对PAR激活的反应被检查，相对于细胞内Ca2+浓度（[Ca2+]i）动力学。在这些腺泡细胞中仅检测到PAR2 mRNA。par2激活肽（PAR2-AP）诱导这些细胞中[Ca2+]i的增加。细胞外Ca2+的去除和Ca2+通道阻滞剂的使用并没有抑制par2 - ap诱导的[Ca2+]i的增加。NO供体模拟PAR2在激活非容性钙进入（NCCE）中的作用。然而，calyculin A和低浓度Gd3+都不能完全阻断par2 - ap诱导的[Ca2+]i的升高。这些发现表明，PAR2激活主要导致细胞内Ca2+储存的Ca2+动员，并且PAR2介导的[Ca2+]i变化主要独立于IP3。我们认为PAR2-AP对NCCE和CCE都有差异调节，主要是NCCE。

Protease-activated receptors (PARs) are G-protein-coupled receptors, activated by proteolytic cleavage. Here, lacrimal gland acinar cell responses to PAR activation were examined, with respect to intracellular Ca2+ concentration ([Ca2+]i) dynamics. Only PAR2 mRNA was detected in these acinar cells. A PAR2-activating peptide (PAR2-AP) induced an increase in [Ca2+]i in these cells. The removal of extracellular Ca2+ and the use of Ca2+ channel blockers did not inhibit PAR2-AP-induced [Ca2+]i increases. The NO donor mimicked the effects of PAR2 in activating non-capacitative calcium entry (NCCE). However, both calyculin A and a low concentration of Gd3+ did not completely block the PAR2-AP-induced increase in [Ca2+]i. These findings indicated that PAR2 activation resulted primarily in Ca2+ mobilization from intracellular Ca2+ stores and that PAR2-mediated [Ca2+]i changes were mainly independent of IP3. We suggest that PAR2-AP differentially regulates both NCCE and CCE, predominantly NCCE.