NOCICEPTOR-LIKE DORSAL ROOT GANGLION NEURONS EXPRESS THE ANGIOTENSIN-II AT2 RECEPTOR THROUGHOUT DEVELOPMENT

ACOSTA C.; SELTZER A, .; BENITEZ S,

Mendoza

Congreso; XXXIV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2016

Sociedad de Biología de Cuyo

Pharmacological and histochemical evidence suggests that the Angiotensin-II type 2 receptor (AT2R) is present in the dorsal root ganglia (DRG) and that this receptor plays a role in neuropathic pain in humans. However, the expression pattern of AT2R during development and the identity of the subpopulation expressing it remain unknown. Using a combination of semi-quantitative PCR, western blotting and immunohistochemistry we examined the expression of AT2R at mRNA and protein levels in rat DRGs from embryonic day 15 (E15) until postnatal day 30 (PN30). We found that AT2R mRNA is present at constant levels from E15 to PN30. A similar different ages. Detailed quantitative analysis of ABC/DAB AT2R staining showed a) that this receptor was present in most neurons at E15 and E18 and b) that postnatally it was predominantly expressed by small DRG neurons. Given that small neurons are putative C-nociceptors and the proposed role of AT2R in neuropathic pain, we next examined whether these AT2R+ve neurons co-localized with Ret and trkA embryonically and with IB4-binding postnatally. We observed that most AT2R+ve neurons were trkA+ve embryonically and IB4-binding postnatally. We also found strong positive statistically highly significant correlations between cytoplasmic AT2R and trkA at E15/E18 and with Ret only at E18. Cytoplasmic AT2R was also strongly and positively correlated with IB4-binding at PN3, 15 and 30. Our evidence demonstrates that AT2R is continuously expressed by a subpopulation of C-nociceptor-like neurons during development.