Nerve growth factor (NGF) in the rat CNS: absence of specific retrograde axonal transport and tyrosine hydroxylase induction in locus coeruleus and substantia nigra

Abstract

Selective, highly efficient uptake of [125I]NGF by nerve terminals followed by retrograde axonal transport, and specific induction of tyrosine hydroxylase by NGF are well known phenomena in peripheral adrenergic neurons of adult rats. In the present study these parameters were used in order to detect possible interactions of NGF with central catecholaminergic neurons. No selective retrograde transport of [125I]NGF could be detected by light microscopic autoradiography from the caudate nucleus to the dopaminergic neurons in the substantia nigra or from the hippocampus to the noradrenergic nerve cells of the locus coeruleus. Biochemically, no change in tyrosine hydroxylase activity could be observed for up to 3 days after injection of either NGF, anti-NGF antibodies, or control proteins close to the nerve cell bodies in the substantia nigra or the locus coeruleus. These data suggest a fundamental difference between central and peripheral adrenergic neurons with regard to their responsiveness of NGF.