Estrogen receptor immunoreactivity in Schwann-like brain macroglia.

Abstract

Olfactory ensheathing cells, tanycytes, pituicytes, pineal glia, retinal Müller cells, and Bergmann glia of normal male rats express concomitantly estrogen receptor, low-affinity neurotrophin receptor, antigen O4, and GFAP, markers characteristic of nonmyelinating Schwann cells. These cells were able to survive and proliferate when cultured from adult tissue, promoted neurite outgrowth, and could guide and ensheath growing neurites. We called this distinct group of growth-promoting central nervous system (CNS) macroglia aldynoglia (Greek: to make grow). Its proliferative and growth-promoting properties seem to be retained during the whole lifetime of the organism in those CNS loci where normal function depends on continuous axon renewal. Aldynoglia plasticity seems totally or partially lost with age where and when it is no longer critical, as in the case of adult cortical and spinal cord radial glia. The concomitant expression of estrogen receptor and low-affinity neurotrophin receptor may promote Schwann-like plasticity of glial cells.