The renin angiotensin system in the auditive pathway during development.

CIUFFO, GLADYS M; SANCHEZ, SUSANA I.; ARCE MA. ELENA

Villa de Merlo

Congreso; XXXV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2017

Sociedad de Biología de Cuyo

The central auditory pathway involves several nuclei located at the midbrain: ventral coclear (VC), locus coeruleus (LC), superior olivary complex (SOC) and the inferior colliculus (IC). In order to evaluate the role of the RAS, we studied Ang II receptor localization at the different nuclei, by means of binding autoradiography, in situ hybridization (ISH) and immunofluorescence during brain development. Coronal sections were obtained at the different ages: postnatal days, PND0, PND8, PND15 in a cryostat. Ang II AT1 receptors were absent at early developmental ages (PND0) at all analyzed nuclei and a low level was observed at the IC at the age PND8. AT2 was present at all ages in IC, LC, VC. Besides, at PND8, AT2 receptors were observed by binding autoradiography at the SOC. The IC is a large midbrain structure which serves as an obligatory synaptic station in both the ascending and descending auditory pathways. We further explored Ang II AT2 receptors at the IC by in situ hybridization and immunofluorescence at PND15, since at this age the highest expression level was present. We demonstrated by ISH that AT2 receptor mRNA localized at the same area recognized by AT2 antibodies at the IC. Immunofluorescence staining with anti-AT2 receptor antibody and anti β III?Tubulin antibody evidence the presence of immunoreactive neurons, confirming previous 3data obtained by binding autoradiography. AT2 receptors might play a role in organogenesis and the establishment of neuronal circuits of the audition pathway.