Immunohistochemical localization of estrogen receptor alpha in the cerebral cortex of the Caiman latirostris (Crocodylia: Alligatoridae)

MORENO PIOVANO GS; DUDIUK C; ROSSETTI M.F; VARAYOUD J; MUÑOZ-DE- TORO M; LUQUE E.H; RAMOS J.G

Huerta Grande, Córdoba, Argentina

Congreso; XXV Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias (SAN) y XII Taller Argentino de Neurociencias (TAN); 2010

The  expression  of  estrogen  receptors  (ERs)  in  the  cerebral  cortex  of  reptiles has  not  been  clearly  established,  although  is  known  that  in  other  species estrogens  are  crucial  for  neuronal  differentiation,  synapse  formation,  and cognitive functions. Caiman latirostris, is a South American species that present temperature-dependent sex determination. By using immunohistochemistry, we have studied the distribution of ER alpha in the cerebral cortex (lateral, medial and dorsal)  of  neonatal  caimans.  Three  groups  of  caimans  were  studied:  females and  males  obtanied  by  temperature  sex  determination  (females  and  males TSD)  and  caimans  feminized  by  in  ovo  administration  of  estradiol  (females HSD). ER alpha was detected in the all cortical areas: medial (MC), dorsal (DC) and lateral cortices (LC). Only the MC showed sex differences at postnatal day 10. The intensity of ER alpha staining was significantly higher in TSD females compared to  males.  Interestingly,  HSD  females  showed  the  maximun  amount  of  ER alpha immunostaining in the MC when compared with both TSD groups. In addition, the  level  of  estradiol  was  significantly  higher  in  females  (both TSD  and  HSD) than  TSD  males.  Double  immunostaining  showed  that  ER alpha  is  expressed  in neurons  as  well  as  in  precursor  cells  (detected  using  anti-GFAP  and  DCX antibodies).  These  observations  demonstrate  that  the  expression  of  ER alpha displays  different  spatial  patterns  on  cortical  cells  and  suggest  that  ER alpha  may play distinct roles in several processes related to brain development.