News and Publications

NeuroZoom: Neuroanatomic Atlases and Databases for Acquisition and Display of Stereologic Data

F. Bloom, P. Sanna, W.G. Young, M. Morales,* A. Trembleau,** E. Battenberg, J. Morrison,*** P. Hof,*** E. Nimchinsky***

* National Institute of Drug Abuse, Baltimore, MD
** Ecole Normale Supérieure, Paris, France
*** Mount Sinai Medical School, New York, NY

Our efforts this past year focused on refining the use of ultrastructural in situ hybridization, mapping the sites of expression of the serotonin receptor 5-HT₃, characterizing cytochemically the neurons that express 5-HT₃ and their possible involvement in the actions of alcohol and other substances of abuse, and using quantitative (stereologic) analysis to examine specific cytochemically defined neurons under a variety of experimental conditions.

We studied the expression of the gene for tyrosine hydroxylase in the locus coeruleus of the rat brain in basal conditions and after pharmacologic stimulation of rats with reserpine. Using electron microscopic in situ hybridization, we found that tyrosine hydroxylase mRNA is localized in both the perikaryal cytoplasm and the nucleus in reserpine-treated animals. The tyrosine hydroxylase RNA in the nucleus corresponds to the primary (hnRNA) transcript, whereas accessory intranuclear aggregates are the mature mRNA transcript devoid of introns. Under basal conditions, many neurons in the locus coeruleus have no detectable intron signal, although all express the gene for tyrosine hydroxylase. Other neurons have high intron labeling and obviously express the gene at a much higher level. When rats are stimulated with reserpine, the number of neurons with detectable intron signal and the intensity of the intron signal per neuron progressively increase rapidly. This finding suggests that neurons expressing tyrosine hydroxylase are progressively recruited for higher expression of the gene for this enzyme as the drug-induced challenge to maintain catecholamine levels progresses.

We have extended our studies on the central nucleus of the amygdala, a component of the brain reward system affected by drugs of abuse. We found that more than 70% of the neurons that express c-fos immunoreactivity after acute ethanol exposure are GABAergic. These results suggest that the GABAergic system of the central nucleus of the amygdala is activated during the rewarding actions of ethanol.

With our collaborators at Mt. Sinai, we used NeuroZoom to examine a specific mouse model of amyotrophic lateral sclerosis, a transgenic mutation of the gene for superoxide dismutase 1. Six mutant and 10 control mice were evaluated daily and were sacrificed when they had severe impairment in the ability to move. Stereologic methods were used to estimate the number of neurons in several cranial motor nuclei and in the spinal cord. In the mutant mice, in all motor structures, the number of neurons was severely reduced (47--73%) and gliosis was extensive. Similar but substantially less marked changes occurred in the oculomotor and hypoglossal nucleus neurons. These findings suggest that the motor nuclei in the brain stem are differentially affected in this model of amyotrophic lateral sclerosis.

PUBLICATIONS

Bloom, F.E., Morales, M. The central 5-HT₃ receptor in CNS disorders. Neurochem. Res. 23:653, 1998.

Cunningham, E.T., Stalder, A., Sanna, P.P., Liu, S., Bloom, F.E., Howes, E.L., Campbell, I.L., Margolis, T.P. Distribution of tumor necrosis factor receptor messenger RNA in normal and herpes simplex virus infected trigeminal ganglia in the mouse. Brain Res. 758:99, 1997.

de Lecea, L., Kilduff, T.S., Peyron, C., Gao, X.-B., Foye, P.E., Danielson, P.E., Fukuhara, C., Battenberg, E.L.F., Gautvik, V.T., Bartlett, F.S., Frankel, W.N., van den Pol, A.N., Bloom, F.E., Gautvik, K.M., Sutcliffe, J.G. The hypoincretins: Hypothalamus-specific peptides with neuroexcitatory activity. Proc. Natl. Acad. Sci. U.S.A. 95:322, 1998.

Fox, H.S., Gold, L.H., Henriksen, S.J., Bloom, F.E. Simian immunodeficiency virus: A model for neuroAIDS. Neurobiol. Dis. 4:265, 1997.

Gallen, C.C., Tecoma, E., Iragui, V., Sobel, D.F., Schwartz, B., Bloom F.E. Magnetic source imaging of abnormal low frequency magnetic activity (ALFMA) in pre-surgical evaluations of epilepsy. Epilepsia 38:452, 1997.

Jacobson, S., Henriksen, S.J., Prospero-Garcia, O., Phillips, T.R., Elder, J.H., Young, W.G., Bloom, F.E., Fox, H.S. Cortical neuronal cytoskeletal changes associated with FIV infection. J. Neurovirol. 3:283, 1997.

Morales, M., Bloom, F.E. The 5-HT₃ receptor is present in different subpopulations of GABAergic neurons in the rat telencephalon. J. Neurosci. 17:3157, 1997.

Morales, M., Criado, J.R., Sanna, P.P., Henriksen, S.J., Bloom, F.E. Acute ethanol induces c-fos immunoreactivity in GABAergic neurons of the central nucleus of the amygdala. Brain Res Interact., in press.

Nelson, C.A., Bloom, F.E. Child development and neuroscience. Child Dev. 68:970, 1997.

Raber, J., O'Shea, R.D., Bloom, F.E., Campbell, I.L. Modulation of hypothalamic-pituitary-adrenal function by transgenic expression of interleukin-6 in the CNS of mice. J. Neurosci. 17:9473, 1997.

Raber, J., Sorg, O., Horn, T.F.W., Yu, N., Koob, G.F., Campbell, I.L., Bloom, F.E. Inflammatory cytokines: Putative regulators of neuronal and neuro-endocrine function. Brain Res. Interact., in press.

Sorg, O., Horn, T.F.W., Yu, N., Gruol, D.L., Bloom, F.E. Inhibition of astrocyte glutamate uptake by reactive oxygen species: Role of antioxidant enzymes. Mol. Med. 3:431, 1997.

Stalder, A.K., Pagenstecher, A., Yu, N., Kincaid, C., Chiang, C.-S., Hobbs, M.V., Bloom, F.E., Campbell, I.L. Lipopolysaccharide-induced IL-12 expression in the central nervous system and cultured astrocytes and microglia. J. Immunol. 159:1344, 1997.

Trembleau, A., Bloom, F.E. Subcellular localization of tyrosine hydroxylase (TH) gene transcripts: New insights into the pattern of TH gene expression in the locus coeruleus under pharmacological stimulation. Biol. Cell 90:39, 1998.