Immunohistochemistry was used to investigate the spatiotemporal distribution of estrogen receptor α and β (ERα, ERβ) in the posteromedial barrel subfield (PMBS) of the cerebral cortex in developing and adult female rats. Counting of immunopositive cells in predefined areas from each layer of the PMBS showed that at PN3, ERα immunoreactivity (IR) was present in every cell, whereas ERβ-IR was not detected. At PN6, about 59% of the cells were ERα immunopositive and low levels of ERβ-IR were observed in scattered cells. At PN18 the proportion of ERα-IR cells decreased to 49%; however, ERβ-IR became widespread and was detected in 39% of cells. By PN25 only faint ERα-IR was observed and in the adults ERα-IR was not detected. In contrast, at PN25 and in adults, ERβ-IR was detected in about half the cells of the PMBS. Regarding the cellular localization of ER-IR, at PN3 an outside-in gradient of cytoplasmic to nuclear localization of ERα-IR was observed. At PN18 and in adults ERβ-IR was preferentially localized to the nucleus of principal neurons, and to the cytoplasm of small, stellate-shaped interneurons. Together, these observations reveal a developmental transition of ER expression in the PMBS; ERα is expressed during early development, ERα and ERβ are co-expressed at later developmental times, and only ERβ is expressed in adults. These changes in ER expression and localization suggest that ERα and ERβ may play important, but different roles in the formation and function of the PMBS region of the primary somatosensory cortex.
- Estrogen receptor
- Posteromedial barrel subfield
ASJC Scopus subject areas
- Developmental Neuroscience
- Developmental Biology