Neuromodulation by polypeptide growth factors: preliminary results on the distribution of epidermal growth factor receptors in adult brain.

Polypeptide growth factors and their receptors are expressed within the brain and neuromodulatory functions are described. Using autoradiography of 125I-epidermal growth factor (EGF) and radioimmunohistochemistry with an antibody to the EGF receptor, we have determined the distribution pattern of the EGF receptor in adult rat brain. The patterns achieved by both methods were similar at every level of the neuroaxis examined. Highest densities of autoradiographic grains were present in the cingulate cortex, cerebral cortex, hippocampus, amygdala and caudate putamen. This pattern of distribution suggests that EGF may have neuromodulatory functions. Common expression of polypeptide receptors by cells of different organ systems constitutes a biochemical basis for homeostatic network regulation.