Atypical lower motor neuron disease with enlargement of Nissl substance: Report of an autopsy case.

The patient was an 81-year-old woman diagnosed with atypical motor neuron disease who died after a long clinical course (7.5 years without mechanical assistance of ventilation) characterized by lower motor neuron signs and symptoms. Upper motor neuron signs and cognitive impairment were not apparent. Autopsy demonstrated severe neuronal loss in the anterior horn of the spinal cord, and some of the remaining neurons showed enlargement of Nissl substance and apparent thickening of the nuclear envelopes. No Bunina bodies, skein-like inclusions, or structures immunoreactive for phosphorylated transactivation response DNA-binding protein 43 were found. Immunoreactivity for superoxide dismutase-1 was focally seen in the enlarged Nissl substance. Ultrastructural examination demonstrated an increase of rough-surfaced endoplasmic reticulum (rough ER) and free ribosomes, disaggregation of polyribosomes, and dispersion of free ribosomes. Cisterns of rough ER were slightly dilated, and some of them were closely attached to the nuclear envelopes. Enlargement of Nissl substance may be related to "ER stress", and the abnormal findings of rough ER and free ribosomes may represent a degenerative process. However, another possibility, that they represent a compensatory hyperplastic change, cannot be excluded. The close attachment of cisterns of rough ER to the nuclear envelopes may be a mechanism to support or compensate for the abnormally-fragile nuclear envelopes.
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Enlargement of the Nissl substance as a manifestation of early damage to spinal cord motoneurons in amyotrophic lateral sclerosis.

AIMS: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of motoneurons. Recent studies indicate that in ALS, degeneration of motoneuron body is late in comparison to degeneration of axons. The morphological consequence of the axonal damage is chromatolysis. Therefore, loss of tigroid in motoneurons as a morphological manifestation of chromatolysis should be a prominent feature seen in an early stage of the disease. To verify that assumption we examined morphologically spinal cord motoneurons in patients with sporadic ALS. MATERIAL AND METHODS: In anterior horn motoneurons of 33 patients tigroid were assessed at light microscopy and morphometrically analyzed. Material was divided into an "acute" ALS group with a duration of the disease of up to 1 year, and a "chronic" ALS group with a clinical course lasting for 4 - 9 years. RESULTS: In the "acute" ALS group, loss of motoneurons was slight, and only a part of them showed central chromatolysis. Instead of chromatolysis the enlargement of the tigroid was found. This phenomenon was observed only in "acute" ALS and confirmed by morphometric analysis. CONCLUSIONS: In ALS, enlargement of the tigroid seems to be an early morphological feature - occuring earlier than central chromatolysis. Its presence may be connected with endoplasmic reticulum stress, disturbed axonal transport or functional compensation of the neuronal deficit.

Endoplasmic Reticulum Stress Is Associated with the Mesencephalic Dopaminergic Neuron Injury in Stressed Rats.

An increasing number of people are in a state of stress due to social and psychological pressures, which may result in mental disorders. Previous studies indicated that mesencephalic dopaminergic neurons are associated with not only reward-related behaviors but also with stress-induced mental disorders. To explore the effect of stress on dopaminergic neuron and potential mechanism, we established stressed rat models of different time durations and observed pathological changes in dopaminergic neurons of the ventral tegmental area (VTA) through HE and thionine staining. Immunohistochemistry coupled with microscopy-based multicolor tissue cytometry (MMTC) was employed to investigate the number changes of dopaminergic neurons. Double immunofluorescence labelling was used to investigate expression changes of endoplasmic reticulum stress (ERS) protein GRP78 and CHOP in dopaminergic neurons. Our results showed that prolonged stress led to pathological alteration in dopaminergic neurons of VTA, such as missing of Nissl bodies and pyknosis in dopaminergic neurons. Immunohistochemistry with MMTC indicated that chronic stress exposure resulted in a significant decrease in dopaminergic neurons. Double immunofluorescence labelling showed that the endoplasmic reticulum stress protein took part in the injury of dopaminergic neurons. Taken together, these results indicated the involvement of ERS in mesencephalic dopaminergic neuron injury induced by stress exposure.

Silver Nanoparticles Conjugate Attenuates Highly Active Antiretroviral Therapy-Induced Hippocampal Nissl Substance and Cognitive Deficits in Diabetic Rats.

BACKGROUND: The application of nanomedicine to antiretroviral drug delivery holds promise in reducing the comorbidities related to long-term systemic exposure to highly active antiretroviral therapy (HAART). However, the safety of drugs loaded with silver nanoparticles has been debatable. This study is aimed at evaluating the effects of HAART-loaded silver nanoparticles (HAART-AgNPs) on the behavioural assessment, biochemical indices, morphological, and morphometric of the hippocampus in diabetic Sprague-Dawley rats. METHODS: Conjugated HAART-AgNPs were characterized using FTIR spectroscopy, UV spectrophotometer, HR-TEM, SEM, and EDX for absorbance peaks, size and morphology, and elemental components. Forty-eight male SD rats (250 ± 13 g) were divided into nondiabetic and diabetic groups. Each group was subdivided into (n = 8) A (nondiabetic+vehicle), B (nondiabetic+HAART), C (nondiabetic+HAART-AgNPs), D (diabetic+vehicle), E (diabetic+HAART), and F (diabetic+HAART-AgNPs). Morris water maze, Y-maze test, and weekly blood glucose levels were carried out. Following the last dose of 8-week treatment, the rats were anaesthetized and euthanized. Brain tissues were carefully removed and postfixed for Nissl staining histology. RESULTS: 1.5 M concentration of HAART-AgNPs showed nanoparticle size 20.3 nm with spherical shape. HAART-AgNPs revealed 16.89% of silver and other elemental components of HAART. The diabetic control rats showed a significant increase in blood glucose, reduced spatial learning, positive hippocampal Nissl-stained cells, and a significant decrease in GSH and SOD levels. However, administration of HAART-AgNPs to diabetic rats significantly reduced blood glucose level, improved spatial learning, biochemical indices, and enhanced memory compared to diabetic control. Interestingly, diabetic HAART-AgNP-treated rats showed a significantly improved memory, increased GSH, SOD, and number of positive Nissl-stained neurons compared to diabetic-treated HAART only. CONCLUSION: Administration of HAART to diabetic rats aggravates the complications of diabetes and promotes neurotoxic effects on the experimental rats, while HAART-loaded silver nanoparticle (HAART-AgNP) alleviates diabetes-induced neurotoxicity.

Modular and laminar pathology of Brodmann's area 37 in Alzheimer's disease.

Previous studies suggested a relationship between severity of symptoms and the degree of neurofibrillary tangles (NFTs) clustering in different areas of the cortex in Alzheimer's disease (AD). The posterior inferior temporal cortex or Brodmann's area (BA 37) is involved in object naming and recognition memory. But the cellular architecture and connectivity and the NFT pathology of this cortex in AD received inadequate attention. In this report, we describe the laminar distribution and topography of NFT pathology of BA 37 in brains of AD patients by using Thionin staining for Nissl substance, Thioflavin-S staining for NFTs, and phosphorylated tau (AT8) immunohistochemistry. NFTs mostly occurred in cortical layers II, III, V and VI in the area 37 of AD brain. Moreover, NFTs appeared like a patch or in cluster pattern along the cortical layers III and V and within the columns of pyramidal cell layers. The abnormal, intensely labeled AT8 immunoreactive cells were clustered mainly in layers III and V. Based on previously published clinical correlations between cognitive abnormalities in AD and the patterns of laminar distributed NFT cluster pathology in other areas of the brain, we conclude that a similar NFT pathology that severely affected BA 37, may indicate disruption of some forms of naming and object recognition-related circuits in human AD.

Pathophysiological changes in the cerebellum and brain stem in a rabbit model after superior petrosal vein sacrifice.

In certain surgical procedures, sacrificing the superior petrosal vein (SPV) is required. Previous studies have reported transient cerebellar edema, venous infarction, or hemorrhage that might occur after sectioning of the SPV. The present study investigated the pathophysiological changes in cerebellum and brain stem after SPV sacrifice. Rabbits were divided into the operation group where the SPV was sacrificed and the control group where the SPV remained intact. Each group was further subdivided into 4, 8, 12, 24, 48, and 72 h groups which represented the time period from sacrificing of the SPV to killing of the rabbits. The water content (WC), Na+ content, K+ content, and pathophysiological changes in cerebellum and brain stem tissue were measured. In comparison with the control, the WC and Na+ content of cerebellar tissue were increased in the 4, 8, 12, and 24 h operation subgroups (P<0.05), but only increased in the 4-h subgroup of the brain stem tissue (P<0.05). The K+ content of the cerebellar tissue decreased in the 4, 8, 12, and 24 h operation subgroups (P<0.05) but only decreased in the 4-h subgroup of brain stem tissue (P<0.05). Nissl staining and TEM demonstrated that cerebellar edema occurred in the 4, 8, 12, and 24 h operation subgroups but not in the 48- and 72-h subgroups. Brain stem edema occurred in the 4-h operation subgroup. In summary, cerebellum and brain stem edema can be observed at different time points after sacrificing of the SPV in the rabbit model.

The selective poly(ADP)ribose-polymerase 1 inhibitor INO1001 reduces spinal cord injury during porcine aortic cross-clamping-induced ischemia/reperfusion injury.

OBJECTIVE: It is well-established that poly(ADP)ribose-polymerase (PARP) assumes major importance during ischemic brain damage, and the selective PARP-1 inhibitor PJ34 reduced spinal cord damage in murine aortic occlusion-induced ischemia/reperfusion injury. We investigated the effect of the PARP-1 inhibitor INO1001 on aortic-occlusion-related porcine spinal cord injury. DESIGN AND SETTING: Prospective, randomized, controlled experimental study in an animal laboratory. PATIENTS AND PARTICIPANTS: Ten anesthetized, mechanically ventilated, and instrumented pigs. INTERVENTIONS: Animals underwent 45 min of thoracic aortic cross-clamping after receiving vehicle (n=5) or intravenous INO1001 (n=5, total dose 4 mg/kg administered both before clamping and during reperfusion). During reperfusion continuous intravenous norepinephrine was incrementally adjusted to maintain blood pressure at or above 80% of the preclamping level. Plasma INO1001 levels were analyzed by HPLC. After 4[Symbol: see text]h of reperfusion spinal cord biopsy samples were analyzed for neuronal damage (hematoxyline-eosine and Nissl staining), expression of the cyclin-dependent kinase inhibitor genes p21 and p27 (immunohistochemistry), and apoptosis (terminal deoxynucleotidyl transferase mediated nick end labeling assay). MEASUREMENTS AND RESULTS: Plasma INO1001 levels were 0.8-2.3 and 0.30-0.76 mM before and after clamping, respectively. While 3-5% of the spinal cord neurons were irreversibly damaged in the INO1001 animals, the neuronal cell injury was three times higher in the control group. Neither p21 and p27 expression nor apoptosis showed any intergroup difference. CONCLUSIONS: The selective PARP-1 inhibitor INO1001 markedly reduced aortic occlusion-induced spinal cord injury. Given the close correlation reported in the literature between morphological damage and impaired spinal cord function, INO1001 may improve spinal cord recovery after thoracic aortic cross-clamping.

[3H]-flunitrazepam-labeled benzodiazepine binding sites in the hippocampal formation in autism: a multiple concentration autoradiographic study.

Increasing evidence indicates that the GABAergic system in cerebellar and limbic structures is affected in autism. We extended our previous study that found reduced [(3)H]flunitrazepam-labeled benzodiazepine sites in the autistic hippocampus to determine whether this reduction was due to a decrease in binding site number (B (max)) or altered affinity (K (d)) to bind to the ligand. Quantitation of hippocampal lamina demonstrated a 20% reduction in B (max) indicating a trend toward a decreased number of benzodiazepine binding sites in the autistic group but normal K (d) values. A reduction in the number of hippocampal benzodiazepine binding sites suggests alterations in the modulation of GABA(A) receptors in the presence of GABA in the autistic brain, possibly resulting in altered inhibitory functioning of hippocampal circuitry.

Neuroprotective effect of G14-humanin on global cerebral ischemia/reperfusion by activation of SOCS3 - STAT3 - MCL-1 signal transduction pathway in rats.

OBJECTIVE: Humanin (HN) has been identified to suppress neuron death. Gly14-HN (HNG), as a variant of HN, can decrease infarct volume after ischemia/reperfusion (I/R) injury. This study aimed to investigate the neuroprotective mechanism of HNG on global cerebral I/R (GI) in rats. METHODS: Rats were randomly divided into 13 groups: Sham group, GI groups and HNG groups. Both GI group and HNG groups included six time points (1, 3, 6, 12, 24, and 72 h). At 24 h after reperfusion, Nissl staining was used to observe positive neurons, and p-STAT3, MCL-1, SOCS3, Bax and Caspase-3 in different groups were detected by immunohistochemistry. qRT-PCR and western blot were used to evaluate the expression of STAT3, p-STAT3, MCL-1, and SOCS3. RESULTS: The immunohistochemistry also showed a significant increase in Bax (0.29 ± 0.007 vs. 0.22 ± 0.007, P < 0.01) and Caspase-3 (0.24 ± 0.02 vs. 0.18 ± 0.006, P < 0.01) in GI group compared with Sham group, while Bax (0.26 ± 0.01 vs. 0.29 ± 0.008, P < 0.01) and Caspase-3 (0.20 ± 0.008 vs. 0.24 ± 0.02, P < 0.01) were significantly decreased by HNG-treatment compared with GI group. Along with immunohistochemistry, western blot and qRT-PCR indicated that the protein and mRNA levels of STAT3, MCL-1, and SOCS3 were up-regulated after administration of HNG at six time points after global cerebral I/R in rat. CONCLUSION: HNG might exert neuroprotective effects through alleviating apoptosis and activating of SOCS3 - STAT3 - MCL-1 signal transduction pathway. Highlights (1) Cerebral ischemia led to neuronal loss in hippocampal CA1 region of rats. (2) HNG had neuroprotective effects on ischemia/reperfusion rats. (3) The protective effect of HNG might be related to the SOCS3 - STAT3 - MCL-1 pathway.

Timing of cord blood treatment after experimental stroke determines therapeutic efficacy.

Embolic stroke is thought to cause irreparable damage in the brain immediately adjacent to the region of reduced blood perfusion. Therefore, much of the current research focuses on treatments such as anti-inflammatory, neuroprotective, and cell replacement strategies to minimize behavioral and physiological consequences. In the present study, intravenous delivery of human umbilical cord blood cells (HUCBC) 48 h after a middle cerebral artery occlusion (MCAo) in a rat resulted in both behavioral and physiological recovery. Nissl and TUNEL staining demonstrated that many of the neurons in the core were rescued, indicating that while both necrotic and apoptotic cell death occur in ischemia, it is clear that apoptosis plays a larger role than first anticipated. Further, immunohistochemical and histochemical analysis showed a diminished and/or lack of granulocyte and monocyte infiltration and astrocytic and microglial activation in the parenchyma in animals treated with HUCBC 48 h poststroke. Successful treatment at this time point should offer encouragement to clinicians that a therapy with a broader window of efficacy may soon be available to treat stroke.

Ethanol withdrawal is required to produce persisting N-methyl-D-aspartate receptor-dependent hippocampal cytotoxicity during chronic intermittent ethanol exposure.

Chronic intermittent ethanol consumption is associated with neurodegeneration and cognitive deficits in preclinical laboratory animals and in the clinical population. While previous work suggests a role for neuroadaptations in the N-methyl-d-aspartate (NMDA) receptor in the development of ethanol dependence and manifestation of withdrawal, the relative roles of ethanol exposure and ethanol withdrawal in producing these effects have not been fully characterized. To examine underlying cytotoxic mechanisms associated with chronic intermittent ethanol (CIE) exposure, organotypic hippocampal slices were exposed to 1-3 cycles of ethanol (50 mM) in cell culture medium for 5 days, followed by 24 h of ethanol withdrawal, in which a portion of slices were exposed to competitive NMDA receptor antagonist (2R)-amino-5-phosphonovaleric acid (APV; 40 µM). Cytotoxicity was assessed using immunohistochemical labeling of neuron-specific nuclear protein (NeuN; Fox-3), a marker of mature neurons, and thionine (2%) staining of Nissl bodies. Multiple cycles of CIE produced neurotoxicity, as reflected in persisting losses of neuron NeuN immunoreactivity and thionine staining in each of the primary cell layers of the hippocampal formation. Hippocampi aged in vitro were significantly more sensitive to the toxic effects of multiple cycles of CIE than were non-aged hippocampi. This effect was not demonstrated in slices exposed to continuous ethanol, in the absence of withdrawal, or to a single exposure/withdrawal regimen. Exposure to APV significantly attenuated the cytotoxicity observed in the primary cell layers of the hippocampus. The present findings suggest that ethanol withdrawal is required to produce NMDA receptor-dependent hippocampal cytotoxicity, particularly in the aging hippocampus in vitro.

Experimental model for repetitive ischemic attacks in the gerbil: the cumulative effect of repeated ischemic insults.

An experimental model for repeated ischemic attacks, which allows easy induction of cerebral ischemia of any desired duration and frequency, has been developed in the gerbil. With this procedure, a pronounced cumulative effect on development of edema and tissue injury was observed using 3 separate, 5-min bilateral occlusions of the common carotid arteries spaced at various time intervals. This effect was most evident when the occlusions were carried out at 1-h intervals, i.e., during the period of marked postischemic hypoperfusion. Such animals, killed after 24 h of recirculation, showed significantly more severe edema and brain tissue injury in the areas exposed to ischemia than was observed in animals killed 24 h after single 5- or 15-min occlusions. The changes of regional CBF, assayed with a [3H]nicotine method, indicated a relatively rapid onset of hypoperfusion of similar degree after each release of arterial occlusion. The hypoperfusion recovered significantly within 6 h of recirculation following either single or multiple occlusions, and no residual hypoperfusion was observed in animals which, when killed at 24 h, showed severe edema and brain tissue injury. This model should prove useful in elucidating the pathophysiological mechanisms operative in repetitive cerebral ischemia.

Ischemia-induced neuronal cell death, calcium accumulation, and glial response in the hippocampus of the Mongolian gerbil and protection by propentofylline (HWA 285).

The localization and timing of cellular calcium loading and glial cell reaction in relation to selective death of hippocampal neurons was studied in Mongolian gerbils following transient forebrain ischemia. Two days after a 5-min period of ischemia, heavy calcium staining was histochemically demonstrated in circumscribed groups of nerve cells, located in the transition zone between the CA1 and CA3 areas. This preceded complete neuronal cell death that was quantitatively assessed by measuring the intensity of Nissl staining. After a 12-min period of ischemia, extensive calcium loading was observed in conjunction with severe neuronal damage throughout the CA1 region as well in the dorsal nuclei of the thalamus. The extent of calcium staining decreased with time and was not seen at stages later than 7 days. Already at 2 days after a 5-min period of ischemia, a strong increase of glial fibrillary acidic protein immunoreactivity was seen. This indicates a marked and early hypertrophy of astrocytes that was not accompanied by an obvious proliferation. Neither the astrocytic response nor the neuronal calcium accumulation were observed in gerbils pretreated with propentofylline, HWA 285 (10 mg/kg, i.p.) 15 min before bilateral carotid artery occlusion. Also, the decrease of Nissl staining in the CA1 area after 5 and 12 min of ischemia was considerably less pronounced and did not significantly differ from sham-operated controls.

Effects of target deprivation on the morphology and survival of adult dorsal column nuclei neurons.

During development, interaction with target cells plays a critical role in the regulation of survival of afferent neurons. In an attempt to define the role of target cells in the adult central nervous system, the somatodendritic morphology and survival of adult cuneate neurons deprived of their targets by in situ injection of kainic acid in the rat thalamus were studied. In neuron-specific, enolase-immunostained sections, a 20% decrease in the mean longest diameter of the labeled cells was detected at 4 months postlesion. This somatic atrophy was accompanied by a loss of distal dendritic arborizations as observed after labeling by intracellular diffusion of horseradish peroxidase. Cytochrome oxidase staining did not reveal detectable alterations of the metabolic activity of these neurons, and an ultrastructural study also failed to demonstrate major changes in the neuronal somata. Cell counts indicated a much delayed death of 25% of the neurons at 10 months postlesion, whereas no neuronal death was detected at 7 months. The glial cells appeared unaltered both in number and in immunolabeling when using OX-42 antibodies or antiglial fibrillary acidic protein (anti-GFAP) antibodies. Results obtained in this time-course study indicate that neuronal death and alteration of the somatodendritic morphology are much delayed events after excitotoxic loss of targets. Somatodendritic atrophy occurs several months postlesion, and neuronal death occurs close to 1 year after lesion. These results suggest that the hypothesis of a necessary continuous trophic support by target cells does not hold as firmly for the adult central nervous system as during development.

Differential dendritic shrinkage of alpha and beta retinal ganglion cells in cats with chronic glaucoma.

PURPOSE: To study changes in the dendritic morphology of retinal ganglion cells (RGCs) in cats with experimental chronic glaucoma. METHODS: Chronic elevation of intraocular pressure (IOP) was produced by injecting endogenous ghost red blood cells into the unilateral anterior chamber of the feline eyes for 1 month. The morphologic features of retrograde-labeled RGCs by bilateral injection of horseradish peroxidase (HRP) into layers A and Aa1 of the lateral geniculate nucleus (LGN) were examined and compared between the normal and glaucomatous eyes. Nissl staining was used for measuring the change in cell density in the retina and the LGN. RESULTS: Quantitative analysis of 720 labeled alpha and beta type RGCs showed that the cell density, body size, maximum dendritic field radius, total dendritic length, and number of branch bifurcations of dendrites decreased significantly in glaucomatous eyes compared with normal ones. The cell loss and shrinkage of dendrites in alpha type ganglion cells in the retina was more pronounced than that in beta type cells. The cell density of all kinds of cells in the retina and LGN monotonically declined with time while IOP was elevated, and cell loss was more significant in large cells than in small ones. CONCLUSION: Progressive cell loss and dendritic damage by chronic elevation of IOP in RGCs and LGN cells are more pronounced in the Y-channel (large cells) than the X-channel (small cells) in feline glaucomatous eyes. The dendritic structure changes and corresponding physiological deficits of RGCs occur before cell death and thus may provide an opportunity for clinical treatment.

Lobar atrophy with pontine neuronal chromatolysis ("ballooned" neurons).

A 64-year-old man developed progressive dementia over a period of 11 years. Postmortem examination showed severe atrophy of the temporal lobes of the brain with extensive neuronal loss and a remarkable alteration of the neuronal perikaryon--the "ballooned" neuron--restricted to the nuclei of the basis pontis. No neuritic plaques, neurofibrillary tangles, or Pick bodies were seen.

Chemical and anatomical changes in the striatum and substantia nigra following quinolinic acid lesions in the striatum of the rat: a detailed time course of the cellular and GABA(A) receptor changes.

The pattern and time-course of cellular, neurochemical and receptor changes in the striatum and substantia nigra were investigated following unilateral quinolinic acid lesions of the striatum in rats. The results showed that in the central region of the striatal lesion there was a major loss of Nissl staining of the small to medium sized cells within 2 h and a substantial loss of neuronal staining within 24 h after lesioning. Immunohistochemical studies showed a total loss of calbindin immunoreactivity, a known marker of GABAergic striatal projection neurons, throughout the full extent of the quinolinic acid lesion within 24 h. Similarly, within 24 h, there was a total loss of somatostatin/neuropeptide Y cells in the centre of the lesion but in the periphery of the lesion these cells remained unaltered at all survival times. Striatal GABA(A) receptors remained unchanged in the lesion for 7 days, and then declined in density over the remainder of the time course. Glial fibrillary acidic protein immunoreactive astrocytes were present in the periphery of the lesion at 7 days, occupied the full extent of the lesion by 4 weeks, and remained elevated for up to 2 months. In the substantia nigra, following placement of a striatal quinolinic acid lesion, there was: a loss of substance P immunoreactivity within 24 h; a marked astrocytosis evident from 1-4 weeks postlesion; and, a major increase in GABA(A) receptors in the substantia nigra which occurred within 2 h postlesion and was sustained for the remainder of the time course (15 months). This study shows that following quinolinic acid lesions of the striatum there is a major loss of calbindin and somatostatin/neuropeptide Y immunoreactive cells in the striatum within 24 h, and a marked increase in GABA(A) receptors in the substantia nigra within 2 h. These findings are similar to the changes in the basal ganglia in Huntington's disease and provide further evidence supporting the use of the quinolinic acid lesioned rat as an animal model of Huntington's disease.

A method for peripheral chromatolysis in neurons of trigeminal and dorsal root ganglia, produced in rats by lithium.

In classical chromatolysis, Nissl bodies are initially lost centrally with subsequent progression to the periphery of the neuron. Peripheral chromatolysis has the opposite pattern; it is less common and more difficult to produce. We describe a new method for producing peripheral chromatolysis in neurons of trigeminal ganglia and dorsal root ganglia that requires only injection of large doses of lithium chloride (LiCl) for two, three or four consecutive daily doses. This method may be useful for elucidating the intraneuronal mechanisms that control the location and structure of the Nissl bodies.

Age-related loss of nerve growth factor sensitivity in rat basal forebrain neurons.

Nerve growth factor (NGF) has recently been implicated as a trophic agent in the survival and maintenance of basal forebrain cholinergic neurons. To test the hypothesis that NGF may play a role in the age-related degeneration of basal forebrain neurons and decline of cerebral cholinergic function, we have used a monoclonal antibody to the NGF receptor, 192 IgG, to immunocytochemically visualize and compare rat basal forebrain neurons responsive to NGF in aged (30 months) and young adult (10 months) rats. In a subpopulation of aged rats, NGF receptor-immunoreactive cells in the basal forebrain appear vacuolated and shrunken, and the neuropil staining is markedly reduced. While no substantial decline in cell density is apparent in Nissl-stained sections, the number of NGF receptor-positive cell profiles within the vertical limb of diagonal band nuclei is reduced by an average of 32% in aged rats. Marked reduction in the expression of NGF receptors in aged rats may signify loss of capacity of the basal forebrain neurons to bind and transport NGF from their terminals in the hippocampus and cortex, subsequent decrease in NGF delivered to the cell bodies, and eventual cellular dysfunction and death of neurons in aging.

Subchronic administration of N-[2-(3,4-dichlorophenyl) ethyl]-N-methyl-2-(dimethylamino) ethylamine (BD1047) alters sigma 1 receptor binding.

BD1047 (N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(dimethylamino)ethylamine) is known to bind with high affinity and selectivity to sigma sites in vitro. In prior in vivo studies, it has been shown to attenuate the dystonic postures and orofacial dyskinesias that are produced by sigma receptor ligands, including the neuroleptic haloperidol. Since abnormal movements, such as dystonic postures and orofacial dyskinesias, are side effects that are associated with many sigma-active neuroleptics, compounds such as BD1047 may have therapeutic potential for preventing and treating these unwanted movements. A possible limitation to the therapeutic potential of BD1047, however, is that at least in cell culture and albeit weak, it can be cytotoxic. Therefore, the present study analyzed the possible neurotoxic effects of in vivo subchronic intracerebroventricular infusion of BD1047 (10 nmol/h) or artificial cerebrospinal fluid (CSF) into rat brains using osmotic minipumps for 7 or 14 days. Following a 24 h wash-out period, the animals were killed, the brains removed, and P2 membranes prepared. Membranes from rats treated for 7 or 14 days with BD1047 showed a marked decrease in [3H](+)-pentazocine binding as compared to membranes from CSF-treated animals, suggesting a loss of sigma 1 receptor binding. Histological examination of brain sections processed for Nissl stains and glial fibrillary acidic protein (GFAP) immunohistochemistry excluded the possibility of a cytotoxically induced down-regulation, suggesting possible receptor internalization or desensitization mediated via sigma 1 sites. Under the conditions used in our study, BD1047 does not appear to be neurotoxic, and the data, when taken together with other studies, suggest that BD1047 acts as a partial agonist at sigma sites.