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Lehman, Michael N.; Karsch, Fred J.; Robinson, Jane E.; Silverman, Ann‐Judith
doi: 10.1002/cne.902730402pmid: 3062047
Electron microscopic immunocytochemistry was employed to examine the ultrastructure of luteinizing hormone‐releasing hormone (LHRH) neurons and their projections to the median eminence in the sheep brain. LHRH perikarya in the preoptic area of anestrous ewes are less innervated than nonimmunoreactive cells in the same sections, but still receive numerous synaptic inputs, primarily onto distal dendrites and small somatic protuberances. Axon terminals synapsing upon LHRH cells contain a combination of clear spherical vesicles and larger dense‐core vesicles. Interestingly, LHRH cell bodies and dendrites are almost entirely surrounded by glial processes. These processes intervene between immunoreactive elements that at a light microscopic level appear to be in contact with each other. Thus no evidence was obtained at the ultrastructural level for contacts among adjacent LHRH cells or dendrites in the preoptic area. Synaptic inputs onto LHRH cell bodies and dendrites appear to penetrate this glial sheath. In contrast to the absence of contacts among LHRH cells in the preoptic area, individual LHRH terminals in the median eminence are often clustered in direct plasma membrane contact. Comparisons between animals of differing reproductive status are needed to determine whether alterations in synaptic inputs, glial ensheathment, or LHRH‐LHRH appositions, may underlie seasonal changes in the activity of LHRH neurons.
Phelps, Patricia E.; Barber, Robert P.; Vaughn, James E.
doi: 10.1002/cne.902730403pmid: 3209733
This report examines the generation of cholinergic neurons in the spinal cord in order to determine whether the transmitter phenotype of neurons is associated with specific patterns of neurogenesis. Previous immunocytochemical studies identified four groups of choline acetyltransferase (ChAT)‐positive neurons in the cervical enlargement of the rat spinal cord. These cell groups vary in both somatic size and location along the previously described ventrodorsal neurogenic gradient of the spinal cord. Thus, large (and small) motoneurons are located in the ventral horn, medium‐sized partition cells are found in the intermediate gray matter, small central canal cluster cells are situated within lamina X, and small dorsal horn neurons are scattered predominantly through laminae III‐V. The relationships among the birthdays of these four subsets of cholinergic neurons have been examined by combining 3H‐thymidine autoradiography and ChAT immunocytochemistry.
Hendrickson, Anita E.; Koontz, Margaret A.; Pourcho, Roberta G.; Sarthy, P. Vijay; Goebel, Dennis J.
doi: 10.1002/cne.902730404pmid: 3209734
Autoradiography following 3H‐glycine (Gly) uptake and immunocytochemistry with a Gly‐specific antiserum were used to identify neurons in Macaca monkey retina that contain a high level of this neurotransmitter. High‐affinity uptake of Gly was shown to be sodium dependent whereas release of both endogenous and accumulated Gly was calcium dependent. Neurons labeling for Gly included 40‐46% of the amacrine cells and nearly 40% of the bipolars. Synaptic labeling was seen throughout the inner plexiform layer (IPL) but with a preferential distribution in the inner half. Bands of labeled puncta occurred in S2, S4, and S5.
Green, Robert C.; Mesulam, M‐Marsel
doi: 10.1002/cne.902730405pmid: 3209735
The AChE fiber distribution within the human hippocampus and parahippocampal gyrus was studied in order to provide normative data for the examination of cholinergic fiberarchitecture in human pathology and to clarify the cytoarchitectonic organization of these structures. A modification of the Koelle method was used to stain temporal lobe serial sections from 6 neurologically normal human brains collected at autopsy.
Masinovsky, Boris; Kempf, Stephen C.; Callaway, Joseph C.; Willows, A. O. Dennis
doi: 10.1002/cne.902730406pmid: 3062048
We reported a development of murine monoclonal antibodies to a molluscan small cardioactive peptide (SCPB) and their application to immunolabeling of neurons in several molluscan and arthropod species. In vitro stimulations of mouse lymphocytes with SCPB conjugated to a carrier protein yielded exclusively IgM class antibodies; in vivo stimulation resulted in generation of both IgM and IgG classes of antibodies. Monoclonal antibodies of the IgM class labeled identified SCP‐containing neuron B11 in the frozen sections of the buccal ganglia of Tritonia diomedia. These antibodies failed to stain any neurons in whole mount preparations. A monoclonal antibody of IgG1 subclass selectively labeled neurons in both frozen sections and whole mount preparations of diverse invertebrate species. Thus, neurons B11, B12, and GE1 and several other neurons of the buccal and gastroesophageal ganglia of T. diomedia bound the antibody, and a similar pattern of immunolabeling was found in the closely related gastropod Tritonia festiva. We also observed SCPB‐like immunoreactivity in the central neurons of other nudibranch and pulmonate molluscs and in examples of insect (Acheta domesticus and Thermobia domestica) and crustacean (Semibalanus cariosus) classes of the Arthropoda. Our results suggest a specific pattern of distribution of SCPB‐like immunoreactivity in the gastropod nervous system and a broad occurrence of SCPB‐like antigenicity in the diverse invertebrates.
doi: 10.1002/cne.902730407pmid: 3062049
Glutamate decarboxylase (GAD) immunohistochemistry was employed at the light and electron microscopic levels to localize GABAergic structures in the basolateral amygdaloid nucleus (BL).
Hardy, Stephen C.; Stein, Barry E.
doi: 10.1002/cne.902730408pmid: 3209736
Previous experiments in cats have shown that complete contralateral visual neglect is produced by removing all known visual cortex on one side of the brain, which can then be reversed by damaging the opposite superior colliculus. Presumably, descending facilitatory influences from the visual cortex to the ipsilateral superior colliculus are counterbalanced by intercollicular inhibition (Sprague: Science 153:1544‐1546, ′66). However, not all of visual cortex or all of the superior colliculus needs to be involved in this circuit. It is the deep rather than the superficial laminae of the superior colliculus that are primarily involved in visual attentive and orientation behaviors, and these laminae are largely independent of primary visual cortex. However, they do depend on corticotectal influences from a comparatively small extraprimary visual area of the posterior region of the lateral suprasylvian cortex (PSSC—Ogasawara et al: J. Neurophysiol. 52:1226‐1245, ′84). The present experiments demonstrate that lesions only a few millimeters in diameter in this corticotectal zone of the PSSC can produce profound visual neglect. While damage to this area has little, if any, effect on superficial laminae visual activity, it produces a dramatic decrease in the visual activity of the deep laminae. These cats with PSSC lesions fail to orient to a visual stimulus that is introduced suddenly into the contralateral visual field, yet they respond on nearly 100% of the trials to this same stimulus when it is presented in the ipsilateral visual field. The lesion‐induced visual neglect produced by PSSC lesions is long‐lasting but can be abruptly ameliorated by a midbrain lesion that primarily involves, or undercuts, the deep laminae of the contralateral superior colliculus. Thus, (1) visual neglect can be produced by depriving the deep laminae of the superior colliculus of visual inputs from the cortex, even when the principal visual cortical regions (17, 18, and 19) and their target structures are intact, and (2) visually guided behavior can be restored by eliminating afferents originating in, or passing through, the deep laminae of the contralateral superior colliculus.
doi: 10.1002/cne.902730409pmid: 2463283
This study summarizes the findings from postmortem examination of the brains of 22 control cases without neurological deficit, 12 cases of senile dementia of the Alzheimer type (SDAT), and nine cases of Parkinson's disease (three without signs of intellectual deterioration, four with dementia, and two atypical with dementia nonresponsive to L‐dopa treatment). The aim of this study was to find the similarities and differences in galanin innervation of the cholinergic basal nucleus neurons in these dementing disorders as compared with controls. Immunocytochemistry with antibodies against galanin peptide and against choline acetyltransferase was applied on perfused brain preparations. Galanin peptide is present in the basal nucleus of Meynert neuron networks in the normal human brain: in local circuit neurons, in a number of galanin/cholinergic neurons, and in a feedback circuit (via collaterals) that terminate upon the cholinergic neuronal somata and dendrites. Thus, peptide galanin circuits could function as powerful modulators of the activities of basal nucleus cholinergic neurons, both within the basal forebrain and in their wider projections to the neocortex and amygdala. As galanin has been shown to inhibit cholinergic activity, this galanin network could suppress the activity of cholinergic neurons. In SDAT, there is a primary loss of cholinergic neurons compounded by a secondary reaction of the remaining cholinergic neurons to the terminal degeneration in the cortex. Galanin networks demonstrate an inverse relationship to the cholinergic cell loss. Galanin axons hypertrophy and hyperinnervate the remaining cholinergic neurons. In Parkinson's disease the loss of cholinergic neurons is accentuated by the presence of dementia: the hypertrophy of the galanin axonal networks on cholinergic neurons is dramatic in Parkinson's disease with dementia.
Fitzpatrick‐MceElligott, Sandra; Card, J. Patrick; Lewis, Michael E.; Baldino, Frank
doi: 10.1002/cne.902730410pmid: 2905365
Individual neurons containing prosomatostatin mRNA were identified with in situ hybridization histochemistry. Our results demonstrate a widespread distribution of prosomatostatin mRNA in several regions of the rat central nervous system. Neurons containing this transcript were most abundant in the anterior olfactory nucleus, hypothalamus, hippocampus, and amygdala as well as in all regions of the cerebral cortex. Moreover, the distribution of mRNA‐containing perikarya was coextensive with the location of neurons containing somatostatin‐like immunoreactivity in all areas of the brain examined. Somatostatin neurons varied in their morphology and amount of hybridization signal from region to region. The widespread distribution and regional variations in neuronal morphology and the amount of hybridization signal are consistent with a neurotransmitter and/or a neuromodulator role for somatostatin in addition to its well‐established neuroendocrine role. These results demonstrate that both the peptide and its mRNA are found in perikarya in the same areas and that they are therefore the sites of synthesis for somatostatin.
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