The expression of ENa super(+)C and ASIC2 proteins in Pacinian corpuscles is differently regulated by TrkB and its ligands BDNF and NT-4

• Published in: Neuroscience letters Vol. 463; no. 2; pp. 114 - 118
• Main Authors: Montano, JA, Calavia, M G, Garcia-Suarez, O, Suarez-Quintanilla, JA, Galvez, A, Perez-Pinera, P, Cobo, J, Vega, JA
• Format: Journal Article
• Language: English
• Published: 01.10.2009
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2009.07.073

Pacinian corpuscles are innervated by large myelinated A alpha - beta axons from the large- and intermediate- sized sensory neurons of dorsal root ganglia. These neurons express different members of the degenerin/epithelial Na super(+) channel (DEG/ENa super(+)C) superfamily of proteins with putative mechanosensory properties, whose expression is regulated by the TrkB-BDNF system. Thus, we hypothesized that BDNF and/or NT-4 signalling through activation of TrkB may regulate the expression of molecules supposed to be necessary for the mechanosensory function of Pacinian corpuscles. To test this hypothesis we analyzed the expression and distribution of ENa super(+)C subunits and acid-sensing ion channel 2 (ASIC2) in Pacinian corpuscles from 25 days old mice deficient in TrkB, BDNF and NT-4. Pacinian corpuscles in these animals are normal in number, structure, and expression of several immunohistochemical markers. Using immunohistochemistry we observed that the beta -ENa super(+)C and gamma -ENa super(+)C subunits, but not the alpha -ENa super(+)C subunit, were expressed in wild- type animals, and they were always found in the central axon. ASIC2 immunoreactivity was found in both the central axon and the inner core cells. The absence of TrkB or BDNF abolished expression of beta -ENa super(+)C and ASIC2, whereas expression of gamma -ENa super(+)C did not change. Expression of beta -ENa super(+)C and gamma -ENa super(+)C subunits in NT-4 deficient mice was found in the axons but also in the inner core cells whereas levels of expression of ASIC2 were increased in these animals. This study suggests that expression in Pacianian corpuscles of some potential mechanosensory proteins is regulated by BDNF, NT-4 and TrkB.