Differential expression of three gap junction proteins in developing and mature brain tissues.

TLDR

The study used antibodies against connexins 26, 32, and 43 to localize gap junction protein expression in specific cell types of frozen adult rodent brain sections. Connexin 32 was found in oligodendrocytes and some neurons, connexins 26 and 43 in leptomeningeal, ependymal, pineal cells and astrocytes, and developmental analysis showed embryonic neuroepithelium expressed connexins 26 and 43 but not 32, with 26 disappearing and 32 increasing postnatally while 43 remained high, indicating cell‑specific distribution and potential functional differences.

Abstract

By using antibodies directed against gap junction proteins of liver (connexins 26 and 32) and heart (connexin 43), we have localized immunoreactivity to specific cell types in frozen sections of adult rodent brains. Connexin 32 reactivity was found in oligodendrocytes and also in a few neurons, whereas reactivity to connexins 26 and 43 was localized to leptomeningeal cells, ependymal cells, and pineal gland. Immunoreactivity with antibodies to connexin 43 also occurred in astrocytes. Furthermore, during embryonic and postnatal maturation of brain tissues, gap junction proteins were differentially expressed. Connexins 43 and 26 predominated in the neuroepithelium of embryonic brains, whereas connexin 32 was virtually absent. Between 3 and 6 weeks after birth, connexin 26 largely disappeared from immature brain; this time course corresponded to the increased expression of connexin 32. Expression of connexin 43 remained high throughout embryonic and postnatal development. These findings demonstrate that gap junction expression in the brain is diverse, with specific cell types expressing different connexins; this cell-specific distribution may imply differences in the function of these intercellular channels in different loci and developmental stages.