Table 2.

Nervous function and neuronal stimulation studies.

Study	Year	Investigated molecules	Type of study	Type of sperimentation	Role in pathogenesis	Role in healing
Fong et al.	2012	Ach, mAch-R, ChAT, VAchT	in vitro	Achilles tendon cells cultures treated with Ach. Immunohistochemical evaluation of cells immunopatterns and EGFR activation		Ach adimistration increase viable cells number, proliferation and activation of the EGFR and ERK1/2 pathways
Bjur et al.	2009	NPY and receptors Y1 and Y2	in vitro	Achilles tendon cell culture from human tendon with tendinosis. Immunohistochemical evaluation	Increased expression of Y1 receptor and NPY was found
Schubert et al.	2005	SP	In vivo	Achilles tendon tissue with tendinosis vs. spontaneous rupture without tendinosis were examined microscopically	Increased number of SP positive fibers was found in tendinosis tendons, and not in spontaneous rupture
Backman et al.	2011	SP, NK-1R	In vivo	Overuse protocol applied in vivo to rabbit Achilles tendons for 1, 3 or 6 weeks vs. controls	Increased SP expression at each time. SP and NK-1R were found in blood vessel walls. NK-1R was also found on tenocytes
Lui et al.	2010	SP, CGRP	In vivo	Collagenase-induced tendinopathy in patellar tendons in rats. Double stance duration before sacrifice assessment and immunohistochemical evaluation		Increased SP and CGRP were found at 2 week, but not at 4 weeks and 8 weeks. A second peak was at 12 weeks and 16 weeks. SP and CGRP changes were consistent with double stance duration
Schizas et al.	2012	SP, NMDAR1, p-NMDAR1, mGluR1, 5, 6, and 7	In vivo	Immunohistochemical evaluation of human patellar tendon tissue with exercise-related tendinopathy	Increased expression of SP, NMDAR1, p-NMDAR1 and mGlutR5 was found in comparison with controls. Co-localization of SP and NMDAR1 was found