Platelet-derived growth factor B-chain-like immunoreactivity in the developing and adult rat brain.

Platelet-derived growth factors (PDGFs) are growth-regulatory molecules that stimulate chemotaxis, proliferation and increased metabolism, primarily of connective tissue cells. In our previous paper, we have demonstrated the ubiquitous localization of PDGF B-chain-containing proteins in neurons and expression of transcripts for PDGF A-chain, B-chain and the two forms of the PDGF receptor in the brains of non-human primates. In the present study, the cellular localization of PDGF B-chain in developing and adult rat brains was analyzed using immunocytochemistry with a PDGF B-chain-specific monoclonal antibody. Intense PDGF B-chain immunoreactivity (PDGFB-I) was distributed around the continuously regenerating primary olfactory neurons at all stages of development from embryo to adult. The major part of PDGFB-I associated with neurons appeared some time after birth and increased with age. PDGFB-I appeared in several nerve fiber systems during earlier stages of development and gradually decreased with age. In conjunction with other data showing the existence of functional PDGF receptor beta-subunits in the neurons, these data suggest a possible role for PDGF B-chain as a neurotrophic or neuroregulatory factor in both developing and mature brains.