Immunohistochemical localization of phospholipase D1 in rat central nervous system

Phospholipase D (PLD) is one of the intracellular signal transduction enzym es and plays an important role in a variety of cellular functions. We inves tigated the distribution of PLD isozyme, PLD1 in the rat brain and spinal c ord using an immunological approach. Western blot analysis showed the prese nce of PLD1 protein in all tissues studied, with significantly higher level s in the brainstem and spinal cord, which was correlated with the results o btained from PLD activity assay. Prominent and specific signals of PLD1 wer e observed in many functionally diverse brain areas, including the olfactor y bulb, medial septum-diagonal band complex, cerebral cortex, brainstem, ce rebellum and spinal cord. In the brainstem, the red nucleus, substantia nig ra, interpeduncular nucleus, cranial motor nuclei (trigeminal motor, abduce nt, facial, and hypoglossal), sensory cranial nerve nuclei (spinal trigemin al, vestibular, and cochlear), as well as nuclei of the reticular formation , all showed intense immunoreactivity. Purkinje cells and deep cerebellar n uclei of the cerebellum were also labeled intensely. However, no significan t labeling was found in the thalamus, epithalamus, and basal ganglia. Altho ugh many of the PLD1 immunoreactive cells were neurons, PLD1 was also expre ssed in glial cells such as presumed astrocytes and tanycytes. These Findin gs suggest that PLD1 may play an important role in the central nervous syst em of the adult rat. (C) 2000 Elsevier Science BN. All rights reserved.