Immunohistochemical localization of Ca2+/calmodulin-dependent protein kinase kinase beta in the rat central nervous system

We examined regional and intracellular distribution of Ca2+ /calmodulin-dep endent protein kinase kinase beta (CaM-KK beta). which activated Ca2+ /calm odulin-dependent protein kinase I and IV (CaM-K I and IV) immunohistochemic ally in the central nervous system of the rat by light and electron microsc opy. Although most neurons in the brain and spinal cord exhibited the immun oreactivity, no labeled neurons were observed in the globus pallidus or ent opeduncular nucleus. and only a small number of neurons showed weak immunor eactivity in the substantia nigra pars reticulata. In general, the immunore activity was observed both in the cytoplasm and cellular nucleus, although the immunoreactivity was not found in the cellular nucleus in some large ne urons such as in the mesencephalic trigeminal nucleus. lateral vestibular n ucleus or gigant cellular reticular formation. As to motoneurons of the cra nial nerve nuclei and the anterior horn of the spinal cord. they revealed t he immunoreactivity both ill the cytoplasm and nucleus. The reaction produc t appeared as fine granules in the cytoplasm and nucleus under light micros copy. Electron microscopic observations: confirmed that the reaction produc t was localized mainly on the Golgi apparatus or on the nuclear chromatin. Immunolabeling for antibody against CaM-KK beta was discussed with the dist ribution of CaM-K I, IV and another CaM-KK, CaM-KK alpha. in the central ne rvous system. (C) 2001 Elsevier Science Ireland Ltd and the Japan Neuroscie nce Society. All rights reserved.