DIAZEPAM-BINDING INHIBITOR FRAGMENT 33-50 (OCTADECANEUROPEPTIDE) IMMUNOREACTIVITY IN THE CEREBELLAR CORTEX IS RESTRICTED TO GLIAL-CELLS

The distribution of octadecaneuropeptide (ODN)-like immunoreactivity ( LI) and its relationship to gamma-aminobutyric acid (GABA)-LI were inv estigated in the cerebellar cortex of adult rats with electron microsc opy. At the electron microscopic level, ODN-LI was found exclusively i n glial cells. In addition to Bergmann glia and its processes, cerebel lar astrocytes were also labelled, encapsulating unlabelled neuronal e lements of the cerebellum. These ODN-LI glial processes were observed in close apposition to synaptic junctions, but immunoreactivity could not be found in the synaptic cleft or in association with neuronal mem branes. Since GABA-LI is always associated with neuronal elements, the colocalization of GABA- and ODN-LI could not be confirmed in the cere bellar cortex. Our results do not support the assumption that ODN is a neuron-specific processing product of diazepam binding inhibitor. (C) 1994 Wiley-Liss, Inc.