ANGIOTENSIN II AT2 RECEPTORS IN THE AUDITORY PATHWAY DURING DEVELOPMENT

ARCE ME; SANCHEZ SI; CIUFFO GM

Potrero de los Funes

Congreso; XLVI reunión anual de SAIB- Potrero de los Funes; 2011

Soc. Arg. de Invest. Bioqca. y Biol. Molecular

Angiotensin II (Ang II) is associated with fluid homeostasis and blood pressure control and can also modulate neuronal activity in regions involved in cognition, motor control and sensory integration. Ang II recognizes two receptor subtypes, named as AT1 and AT2. Previously, we studied Ang II receptor localization during cerebellar development, which peaked at P15. The inferior colliculus (IC) is a relay station in the ascending auditory pathway at the midbrain, serving as a major integrative center within the central auditory system. We performed a study of Ang II receptor localization by autoradiography and immunohistochemistry and mRNA expression by RT-PCR during postnatal development in rat midbrain and hindbrain. Specific binding at the IC increased with age, maximal in P15 rats (P <0.001) with prevalence of AT2 receptors, in coincidence with maximal mRNA AT2 receptor expression at this stage. Interestingly, the ventral and dorsal coclear nuclei, involved in the auditory pathway also exhibited binding to AT2 receptors in the P8 and P15 rat brainstem. The pattern of Ang II AT2 receptors expression in the IC encompasses the pattern of brainstem maturation and connection with the cerebral system. Since the onset of hearing in the rat, happens around P12, we can assume that AT2 receptors might play a potential role in organogenesis and the establishment of neuronal circuits.