Expression of Protease-Activated Receptor 3 in the Trigeminal and Dorsal Root Ganglion of adult rats using immunohistochemistry

Abstract

Protease-activated receptors (PARs) have been implicated in a variety of human physiological and pathophysiological processes, including; nociception, neuroinflammation, neuroprotective and neurodegenerative pathways (Peters and Henry, 2009; Adams et al. 2011). PAR3 was discovered as a second thrombin receptor in 1997, and since then few papers have been published which assess its expression in the nervous system (Ishihara et al. 1997). This paper investigates the expression of PAR3 in sensory neurons of the trigeminal ganglion (TG) and dorsal root ganglion (DRG) of naïve adult rats. Immunohistochemistry showed PAR3 to be strongly expressed in non-neuronal cells of both the TG and DRG. Further analysis showed these cells to be non-myelinating satellite cells and myelinating Schwann cells, both showing strong co-expression of PAR3 and S-100. The expression of PAR3 in sensory neurons proved too difficult to accurately determine. This study concludes that further research, using multiple methods of analysis, is required to accurately describe the distribution and quantification of PAR3 positive sensory neurons within the TG and DRG of naïve adult rats. This study does however show strong PAR3 expression in non-neuronal satellite cells and Schwann cells of both the TG and DRG of naïve adult rats.