Biomedical subjects

B H Wainer

Publications and source records attributed to B H Wainer.

At least 55 records · Page 3Linked to original sources

PubMed1991

Immortalization of embryonic mesencephalic dopaminergic neurons by somatic cell fusion.

To facilitate the study of trophic interactions between mesencephalic dopaminergic neurons and their target cells, clonal hybrid cell lines have been developed from rostral mesencephalic tegmentum (RMT) of the 14-day-old embryonic mouse employing somatic cell fusion techniques. Among the hybrid cell lines obtained, one contains a high level of dopamine (DA), another predominantly 3,4-dihydroxyphenylalanine (DOPA), and a third no detectable catecholamines. The hybrid nature of the cell lines is supported by karyotype analysis and by the expression of adhesion molecules as assessed by aggregation in rotation-mediated cell culture. The DA cell line shows neuronal properties including catecholamine-specific histofluorescence, neurite formation with immunoreactivity to neurofilament proteins, and large voltage-sensitive sodium currents with the generation of action potentials. In contrast to the pheochromocytoma cell line (PC12), the dopamine content of the DA hybrid cell line is depleted by low concentrations of N-methyl-4-phenylpyridinium ion (MPP+), the active metabolite of the neurotoxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

1-Methyl-4-phenylpyridinium↗

PubMed1991

In vitro cell cultures as a model of the basal forebrain.

The basal forebrain has attracted considerable attention because of its putative role in complex functions such as learning, memory and behavioral state control as well as its vulnerability in neurological disorders such as Alzheimer's Disease (AD). The finding that nerve growth factor provides trophic support for the cholinergic basal forebrain neurons has stimulated further interest in understanding trophic interactions of basal forebrain neurons as well as in possible trophic factor therapeutic strategies for disease states. Our laboratory has utilized primary cell cultures and developed immortalized central nervous system cell lines to study the trophic interactions that establish and maintain the septohippocampal pathway, a basal forebrain component which plays an essential role in cognitive function and is prominently affected in AD. The results of our primary cell culture studies have demonstrated the importance of trophic signals elaborated by the hippocampus in mediating the development of septal cholinergic neurons. Nerve growth factor plays an important role in this process, but it cannot account for all of the trophic signals elaborated by authentic hippocampal target cells. The development by this laboratory of clonal cell lines of septal and hippocampal lineage offers the prospect of investigating both the response to and elaboration of neural trophic signals at a more precise level of resolution than can be achieved with primary cultures. The technology and information that is generated from the engineering of such cell lines will also serve as a strategy to study trophic interactions in other brain circuits in future years, and to investigate possible changes or dysfunctions that occur neurological diseases.

Alzheimer Disease↗

PubMed1990

Ultrastructure of cholinergic synaptic terminals in the thalamic anteroventral, ventroposterior, and dorsal lateral geniculate nuclei of the rat.

The principal relay nuclei of the thalamus receive their cholinergic innervation from two midbrain cholinergic groups: the pedunculopontine tegmental nucleus and the laterodorsal tegmental nucleus. The different thalamic nuclei exhibit populations of cholinergic axons which vary in density and morphology when examined at the light microscopic level. However, the ultrastructure of the cholinergic terminals in different thalamic nuclei has not been described. This study was undertaken to confirm that synaptic contacts are formed by cholinergic axons in several principal thalamic relay nuclei, to describe their ultrastructural morphology, and to identify the types of postsynaptic elements contacted by cholinergic synaptic terminals. The thalamic nuclei examined in this study are the dorsal lateral geniculate nucleus, ventroposteromedial nucleus, ventroposterolateral nucleus, and anteroventral nucleus. Our results confirm that cholinergic axons form synaptic terminals in these thalamic nuclei. Cholinergic synaptic terminals contact structures outside the characteristic synaptic glomeruli, are never postsynaptic, and have morphologies and postsynaptic targets which differ among the thalamic nuclei. In the ventroposterior nuclei, cholinergic terminals form asymmetric synaptic contacts onto larger dendrites in the extraglomerular neuropil. In the anteroventral nucleus, cholinergic terminals form both symmetric and asymmetric synaptic contacts onto dendrites and somata. Cholinergic terminals in the anteroventral nucleus are larger than those in other nuclei. In the dorsal lateral geniculate nucleus, cholinergic terminals contact both somata and dendrites in the extraglomerular neuropil, but the synaptic contacts in this nucleus are symmetric in morphology.

Animals↗

PubMed1990

Development and characterization of clonal cell lines derived from septal cholinergic neurons.

Studies employing primary cells to determine the molecular basis of neuronal development and selective synaptogenesis in the central nervous system are limited by cellular heterogeneity. Clonal hybrid cell lines derived from a particular region of brain, which express differentiated characteristics typical of the cells of origin, offer a potentially powerful alternative approach. We previously demonstrated the feasibility of deriving such cell lines from septal cholinergic cells. We now delineate the methods employed, and describe the development of additional cholinergic cell lines expressing neuronal and cholinergic features from later developmental stages. One cell line has been studied in detail and found to form neurites, express choline acetyltransferase (ChAT) and neurofilament protein (NFP), and display typical neuronal ultrastructural characteristics, including puncta adherens, neuritic varicosities, vesicles, and growth cones.

Animals↗

PubMed1990

Immortalized young adult neurons from the septal region: generation and characterization.

Studies of the development of the central nervous system would be greatly facilitated by the ability to immortalize neuronal tissue from a broad range of ages. We have previously used somatic cell fusion techniques to generate neuronal cell lines from embryonic mice. To immortalize older neuronal cells, a cell isolation technique was developed to obtain viable septal cells from postnatal day 21 mice. The septal cells were fused to N18TG2 neuroblastoma cells and then cultured in selective medium to isolate septum x neuroblastoma cell lines. The hybrid nature of the lines was verified by chromosome analysis and electrophoretic analysis of glucosephosphate isomerase isozymes. The lines express phenotypes typical of differentiated septal neurons. Many lines morphologically resemble neurons and express the high molecular weight neurofilament protein. Several lines express high levels of choline acetyltransferase activity; others synthesize nerve growth factor. These results demonstrate that young adult neuronal tissue can be immortalized and that hybrid cells express properties of the neuronal parent.

Animals↗

PubMed1990

Nerve growth factor expression in the developing hippocampus isolated in vitro.

Nerve growth factor (NGF) is synthesized in the hippocampus and neocortex and provides trophic support for afferent cholinergic neurons of the basal forebrain. To determine the capacity of the developing hippocampus to express NGF in the absence of NGF-responsive afferents, embryonic hippocampal cells isolated prior to septal innervation were studied in reaggregating cell culture. The expression of NGF protein in vitro was qualitatively and quantitatively similar to that observed in situ. The expression of NGF mRNA exhibited an initial increase in vitro but then plateaued and was maintained at a steady level. This latter finding was in contrast to the steady rise in NGF mRNA levels observed in situ. These data suggest that (i) intrinsic hippocampal interactions regulate the onset of NGF expression, but that (ii) additional extrinsic developmental signals may be required for proper regulation of hippocampal NGF expression during ontogeny.

Aging↗

PubMed1990

Neuronal properties and trophic activities of immortalized hippocampal cells from embryonic and young adult mice.

The hippocampal formation elaborates trophic factors such as nerve growth factor (NGF) to support the cholinergic innervation it receives from the septal region. To further study the trophic interactions of this pathway, hippocampal cells from embryonic day 18 and postnatal day 21 mice were immortalized via somatic cell fusion to N18TG2 neuroblastoma cells. The hippocampal cell lines exhibit morphological and cytoskeletal features which are typical of their neuronal parents but which are not expressed by the neuroblastoma parent. When differentiated with retinoic acid, the hippocampal cell lines exhibit electrophysiological features similar to cultured hippocampal neurons. Many of the lines constitutively express high levels of NGF, and at least one cell line exerts a non-NGF trophic effect on the expression of choline acetyltransferase by septal neurons in vitro. These cell lines are potentially useful for investigating the neurochemical and excitable properties of hippocampal neurons and identifying novel trophic activities that promote the development and maintenance of the septohippocampal pathway.

Animals↗

PubMed1989

Correlated light and electron microscopic study of dopaminergic neurons and their synaptic junctions with DARPP-32-containing cells in three-dimensional reaggregate tissue culture.

An antibody to tyrosine hydroxylase has been used in a correlated light and electron microscopic study to characterize dopaminergic neurons and synaptic junctions in three-dimensional reaggregate cell culture. Dissociated fetal mesencephalic cells containing dopamine neurons were coaggregated with dissociated fetal striatal cells in rotatory culture for 21 days. Sections of the coaggregates were stained by the peroxidase anti-peroxidase technique to reveal tyrosine hydroxylase-immunoreactive structures. Clusters of immunoreactive perikarya as well as dendrites and axons were observed. Immunolabeled perikarya were round or oval and approximately 20 microns in diameter. Boutons immunoreactive for tyrosine hydroxylase formed symmetric synapses, primarily with unlabeled dendritic shafts. Symmetric membrane specializations were also observed between tyrosine hydroxylase-positive boutons and unlabeled dendritic spines as well as with the perikaryon of an unlabeled medium-size neuron possessing a slightly indented nucleus. To characterize the neurochemical nature of the neurons postsynaptic to tyrosine hydroxylase-positive boutons in the reaggregates, an antibody against DARPP-32 (a dopamine and adenosine 3':5'-monophosphate-regulated phosphoprotein) and an antibody against tyrosine hydroxylase were employed to visualize striatal dopaminoceptive neurons and dopaminergic structures, respectively, in the same section. Examination of reaggregate sections at the light microscopic level demonstrated that DARPP-32-immunoreactive cells were distributed into discrete clusters that were associated with patches of tyrosine hydroxylase-positive axonal varicosities. Ultrastructural analysis of tyrosine hydroxylase-positive boutons in such clusters revealed that dopaminergic axons synaptically contacted DARPP-32-immunoreactive neurons as well as unlabeled neuronal structures.

Animals↗

PubMed1989

An atlas of the regional and laminar distribution of choline acetyltransferase immunoreactivity in rat cerebral cortex.

The distribution of cholinergic fibers in rat cortex was investigated using choline acetyl-transferase immunohistochemistry. Previous studies have either shown differences in distribution, but have been limited to selected areas, or have shown no discernable differences between different cortical areas. In our study, we examined all areas of rat cortex and found that there are striking interareal and interlaminar differences in cholinergic fiber distribution. We have found that certain functionally similar cortical areas (e.g. sensory, motor, etc.) have similar patterns of cholinergic innervation and we have designated 13 general patterns of cortical cholinergic innervation. We have also compared, on an area-by-area basis, the pattern of acetylcholinesterase reactivity to that of choline acetyltransferase immunoreactivity, since acetylcholinesterase has been used for many years as a putative cholinergic marker. We found that in most cortical areas, the distribution of acetylcholinesterase-positive fibers paralleled that of choline acetyltransferase-immunoreactive fibers; however, there were some striking differences, notably primary somatosensory (the "barrelfield"), retrosplenial and cingulate cortices. In some areas, a revised concept of rat cortical organization, using cytoarchitectonics, was required. The results of this study provide a comprehensive microscopic analysis of cholinergic fiber innervation of the rat cortex. These results are discussed in relation to previous anatomical, physiological and pharmacological studies of cortical cholinergic innervation. The possible sources of this innervation are also discussed.

Animals↗

PubMed1989

The effects of nerve growth factor on the development of septal cholinergic neurons in reaggregate cell cultures.

Recent studies suggest that nerve growth factor is present within the central nervous system where it may exert selective trophic effects on cholinergic neurons. We have measured the effects of nerve growth factor on septal cholinergic neurons in three-dimensional reaggregating cell cultures, a system which closely simulates the cellular environment in situ. Septal cells obtained from 15-day-old mouse embryos were dissociated into a single cell suspension and then allowed to reaggregate in culture in a rotary incubator shaker. After 17 days in culture, half of the reaggregates from a flask were sonicated for measurement of choline acetyltransferase activity, and the remaining reaggregates were processed for acetylcholinesterase histochemistry. Addition of nerve growth factor to medium containing septal reaggregates resulted in greater than a three-fold increase in choline acetyltransferase activity and in the number of acetylcholinesterase-positive cells, as well as an enhancement in the staining of acetylcholinesterase-positive fibers. All of these effects of nerve growth factor could be neutralized by antibodies to nerve growth factor. In order to evaluate the possible role of endogenous hippocampal-derived nerve growth factor, antiserum to nerve growth factor was added to the culture media containing septal-hippocampal coaggregates. After 21 days in culture, the presence of nerve growth factor antibodies did not qualitatively affect the pattern or density of cholinergic fibers observed. Synapse formation between cholinergic axons and hippocampal target cells was still in evidence as revealed by electron microscopy. However, there was a modest decrease in choline acetyltransferase activity (20%) and cholinergic cell number (30%) when compared with coaggregates grown in culture medium either without nerve growth factor antiserum or with non-immune serum. The magnitude of these effects was markedly less than the effects observed when exogenous nerve growth factor was added to septal cells grown alone in reaggregate culture. These results suggest that nerve growth factor may play a role during central cholinergic development, but that additional trophic mechanisms are likely to be required.

Animals↗

PubMed1988

Ultrastructure of ChAT-immunoreactive synaptic terminals in the thalamic reticular nucleus of the rat.

The thalamic reticular nucleus has been shown to receive cholinergic innervation from both the nucleus basalis of Meynert in the forebrain and the pedunculopontine and laterodorsal tegmental nuclei in the brainstem (Steriade et al.: Brain Res. 408:372-376, '87; Levey et al.: Neurosci. Lett. 74:7-13, '87). Relatively dense populations of choline acetyltransferase-(ChAT) immunoreactive axons and terminallike varicosities have been shown to be distributed throughout this nucleus (Levey et al.: J. Comp. Neurol. 257:317-332, '87). In this study, the ultrastructure of ChAT-immunoreactive axons and of their synaptic terminals in the reticular nucleus was examined in the electron microscope. All ChAT-immunoreactive axonal profiles in the reticular nucleus were presynaptic; the postsynaptic elements were exclusively dendritic profiles; and no axo-axonic or axosomatic contacts from labelled axons were observed. Most ChAT-immunoreactive synaptic contacts were made by profiles less than 0.25 micron in minor diameter. Single ChAT-immunoreactive axons made synaptic contact with several dendritic profiles as the axons were followed through serial sections. These results suggest that the cholinergic innervation of the reticular nucleus will modulate the function of reticular neurons by synapsing onto the dendrites of its neurons without direct effect on the corticothalamic and thalamocortical terminals which also innervate the reticular nucleus.

Animals↗

PubMed1988

Cholinergic vs. noncholinergic efferents from the mesopontine tegmentum to the extrapyramidal motor system nuclei.

Previous studies have suggested that the pedunculopontine tegmental nucleus (PPTn) is reciprocally connected with extrapyramidal motor system nuclei (EPMS) whereas other studies have implicated the PPTn in behavioral state control phenomena such as sleep-wakefulness cycles. Many of these studies define the nonprimate PPTn as an area of mesopontine tegmentum which is labeled from injections of anterograde tracers into the basal ganglia. Recently, we have defined the rat PPTn as a large-celled, cholinergic nucleus. The rat PPTn is cytologically distinct from a group of smaller, noncholinergic neurons that are medially adjacent to the PPTn. This noncholinergic group is further distinguished from the PPTn by its afferent input from the globus pallidus, entopeduncular nucleus, and substantia nigra. We refer to the latter area as the midbrain extrapyramidal area (MEA). Using combined choline acetyltransferase immunohistochemistry of the PPTn and WGA-HRP retrograde tracing from the EPMS, we investigated the efferent connections of the MEA and PPTn to the EPMS in the rat. The noncholinergic MEA, rather than the PPTn, is the major source of tegmental innervation to the globus pallidus, caudate-putamen, subthalamic nucleus, entopeduncular nucleus, substantia nigra, and motor cortex. In contrast, the cholinergic PPTn is the major source of tegmental innervation to the ventrolateral thalamic nucleus. This finding is in contradistinction to thalamic projections from the surrounding reticular formation, which are identified only after WGA-HRP injections into "nonspecific" thalamic nuclei. This body of evidence suggests that the noncholinergic MEA represents an additional component of the EPMS and may correspond to the "mesencephalic locomotor region." The cholinergic PPTn may play a role in more global thalamic functions such as the "reticular activating system" rather than a primary role in motor function.

Animals↗

PubMed1988

Ascending projections from the pedunculopontine tegmental nucleus and the adjacent mesopontine tegmentum in the rat.

Ascending projections from the pedunculopontine tegmental nucleus (PPT) and the surrounding mesopontine tegmentum to the forebrain in the rat are here examined by using both retrograde and anterograde tracing techniques combined with choline acetyltransferase (ChAT) immunohistochemistry. The anterogradely transported lectin Phaseolus vulgaris-leukoagglutinin (PHA-L) was iontophoretically injected into the PPT in 12 rats. Anterogradely labelled fibers and varicosities were observed in the thalamic nuclei, confirming the findings of our previous retrograde studies (Hallanger et al: J. Comp. Neurol. 262:105-124, '87). In addition, PHA-L-labelled fibers and varicosities suggestive of terminal fields were observed in the anterior, tuberal, and posterior lateral hypothalamic regions, the ventral pallidum in the region of the nucleus basalis of Meynert, the dorsal and intermediate lateral septal nuclei, and in the central and medial nuclei of the amygdala. To determine whether these were cholinergic projections, the retrograde tracer WGA-HRP was injected into terminal fields in the hypothalamus, septum, ventral pallidum, and amygdala. Numerous ChAT-immunoreactive neurons in the PPT and laterodorsal tegmental nucleus (LDT) were retrogradely labelled from the lateral hypothalamus. These cholinergic neurons constituted over 20% of those retrogradely labelled in the dorsolateral mesopontine tegmentum; the balance consisted of noncholinergic neurons of the central tegmental field, retrorubral field, and cuneiform nucleus. Following placement of WGA-HRP into dorsal and intermediate lateral septal regions, the vast majority (greater than 90%) of retrogradely labelled neurons were cholinergic neurons of the PPT and LDT, with few noncholinergic retrogradely labelled neurons in the adjacent tegmentum. In contrast, fewer cholinergic neurons were retrogradely labelled following placement of tracer into the nucleus basalis of Meynert or into the central, medial, and basolateral nuclei of the amygdala, while numerous noncholinergic neurons of the central tegmental field rostral to the PPT and of the retrorubral field adjacent to the PPT were retrogradely labelled in these cases. These anterograde and retrograde studies demonstrate that cholinergic PPT and LDT neurons provide a substantial proportion of mesopontine tegmental afferents to the hypothalamus and lateral septum, while projections to the nucleus basalis and the amygdala are minimal.

Afferent Pathways↗

PubMed1988

Cholinergic projections from the laterodorsal and pedunculopontine tegmental nuclei to the pontine gigantocellular tegmental field in the cat.

This study demonstrates that the laterodorsal tegmental nucleus (LDT) and pedunculopontine tegmental nucleus (PPT) are sources of cholinergic projections to the cat pontine reticular formation gigantocellular tegmental field (PFTG). Neurons of the LDT and PPT were double-labeled utilizing choline acetyltransferase immunohistochemistry combined with retrograde transport of horseradish peroxidase conjugated with wheat germ agglutinin (WGA-HRP). In the LDT the percentage of cholinergic neurons retrogradely labeled from PFTG was 10.2% ipsilaterally and 3.7% contralaterally, while in the PPT the percentages were 5.2% ipsilaterally and 1.3% contralaterally. These projections from the LDT and PPT to the PFTG were confirmed and their course delineated with anterograde labeling utilizing Phaseolus vulgaris leucoagglutinin (PHA-L) anterograde transport.

Animals↗

PubMed1988

Medullary and spinal efferents of the pedunculopontine tegmental nucleus and adjacent mesopontine tegmentum in the rat.

The medullary and spinal efferents of the pedunculopontine tegmental nucleus and adjacent mesopontine tegmentum were investigated by employing (1) the anterograde autoradiographic methodology and (2) the retrograde transport of HRP and/or WGA-HRP in combination with choline acetyltransferase immunohistochemistry. The anterograde experiments identified five descending pathways from the mesopontine tegmentum: (1) Probst's tract, which descends in the dorsolateral reticular formation in close relation to the nucleus of the solitary tract; (2) a ventrolateral branch of Probst's tract that extends ventrolaterally alongside the spinal trigeminal nucleus; (3) a ventromedial branch of Probst's tract that extends ventromedially through the gigantocellular field of the medulla; (4) the medial reticulospinal tract, which descends in parallel with the medial longitudinal fasciculus and turns ventrolaterally along the dorsal surface of the inferior olive to enter the ventrolateral funiculus of the spinal cord; and (5) a crossed ventromedial pathway, which descends in a ventral paramedian position through the magnocellular field of the medulla. The origins of these pathways reflected a rough lateral-to-medial topography of mesopontine tegmental cell groups. The parabrachial nucleus, situated furthest laterally, for example, projected primarily through Probst's tract and its ventrolateral branch. The pedunculopontine tegmental nucleus, midbrain extrapyramidal area, and the subceruleal region, situated more medially, projected descending axons largely through the ventromedial branch of Probst's tract. The pontine tegmental field, situated furthest medially and ventromedially, was the largest contributor to the medial reticulospinal tract. The retrograde transport experiments confirmed these general organizational features. The combination of retrograde transport with choline acetyltransferase immunohistochemistry established that the cholinergic pedunculopontine tegmental nucleus contributes a large portion to the mesopontine tegmental innervation of the medullary reticular formation. A much smaller number of cholinergic pedunculopontine neurons project as far as the spinal cord. Spinal projections from the mesopontine tegmentum originate largely from non-cholinergic neurons of the midbrain extrapyramidal area, subceruleal region, Kölliker-Fuse division of the parabrachial nucleus, and pontine tegmental field.

Animals↗

PubMed1988

Immunohistochemistry of choline acetyltransferase in the guinea pig brain.

Choline acetyltransferase (ChAT) was localized immunohistochemically within the brain of the guinea pig using a monoclonal antibody. ChAT was found in the cytoplasm of cell bodies and primary dendrites of neurons located in striatum, basal forebrain, cranial nerve motor nuclei and scattered cells in the pons. The greatest numbers of immunoreactive neurons were located in the diagonal band of Broca, medial septum and striatum. Distinct immunoreactive fibers were not visible using this antibody, although a diffuse immunostaining was present in the same nuclear regions as well as in the nerve roots of cranial nerve nuclei and the interpeduncular nuclei. Results of the present study agree closely with other previous reports of acetylcholine distributions.

Animals↗

PubMed1988

Ultrastructural evidence for hippocampal target cell-mediated trophic effects on septal cholinergic neurons in reaggregating cell cultures.

We have previously demonstrated at the light microscopic level that when embryonic day-15 septal neurons are co-cultured for 21 days with their target cells from the hippocampus, increased numbers of septal cholinergic neurons are present as compared with co-cultures employing cells from the non-target cerebellum. In addition, fine varicose axon-like cholinergic fibers are found to be associated with the hippocampal cells but not with cerebellar cells. We now provide ultrastructural evidence for hippocampal target cell-enhanced cholinergic neuronal survival, axonal proliferation, and synapse formation in this culture system. Dissociated cell suspensions from septal, hippocampal, and cerebellar areas were obtained from 15-day mouse embryos; and hippocampal and cerebellar cells were internally labeled with rhodamine-conjugated wheat germ agglutinin. Combinations of septal and hippocampal cells, and septal and cerebellar cells were allowed to reaggregate in rotation mediated culture for either 15 or 21 days. The reaggregates were then fixed, embedded, sectioned, and processed for acetylcholinesterase-positive acetylcholinesterase-positive cells and fibers, and under fluorescence to locate rhodamine-labeled cell populations. Representative reaggregate profiles were then re-embedded for electron microscopic examination. In both types of reaggregates, either labeled hippocampal target or cerebellar non-target cells segregated from the septal cells so that areas containing each of the respective cell populations could be studied. In sections of septal-hippocampal reaggregates from 15-day cultures, 571 out of 665 (85%) cholinergic neurons examined were intact, whereas 15% of the cells showed some ultrastructural features of degeneration. Similarly, at day 21, 297 out of 335 (88%) of the cholinergic neurons were intact. In sections of septal-cerebellar reaggregates from 15-day cultures, 473 out of 572 (83%) cholinergic neurons were intact. By day 21 of culture, however, only 15 out of 110 (14%) cholinergic neurons examined were intact from the septal-cerebellar reaggregates. In areas of septal-hippocampal reaggregates occupied by rhodamine-labeled hippocampal cells, profiles of acetylcholinesterase-labeled axons were identified, and synaptic specializations were observed between cholinergic terminals and dendrites as well as somata of hippocampal target cells. In contrast, areas of septal-cerebellar reaggregates occupied by rhodamine-labeled cerebellar cells were devoid of cholinergic fibers.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholinesterase↗

PubMed1987

Cortical effects of neurotoxic damage to the nucleus basalis in rats: persistent loss of extrinsic cholinergic input and lack of transsynaptic effect upon the number of somatostatin-containing, cholinesterase-positive, and cholinergic cortical neurons.

Ibotenic acid injections into the nucleus basalis (Ch4) resulted in a near-total loss of cortical cholinesterase fibers. This loss of cholinergic input is irreversible for at least 6 months. The degeneration of cholinergic input has no transsynaptic effect upon the number of cortical somatostatinergic, cholinergic and cholinesterase-positive (cholinoceptive) neurons.

Acetylcholinesterase↗