Cholinergic denervation in patients with idiopathic rapid eye movement sleep behaviour disorder.

BACKGROUND AND PURPOSE: Cholinergic dysfunction appears to play a role in the cognitive impairment observed in Parkinson's disease and dementia with Lewy bodies. The occurrence of cholinergic dysfunction in the early stages of these conditions, however, has not been investigated. The objective of this study was to investigate cholinergic function in patients with idiopathic rapid eye movement sleep behaviour disorder (iRBD), a disorder recognized to be an early stage of both Parkinson's disease and dementia with Lewy bodies. METHODS: A total of 21 patients with polysomnography-confirmed iRBD with no evidence of parkinsonism and cognitive impairment and 10 controls underwent positron emission tomography (PET) to assess brain acetylcholinesterase levels (11 C-donepezil PET) and nigrostriatal dopaminergic function (18 F-DOPA PET). Clinical examination included the Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III, Mini Mental State Examination and Montreal Cognitive Assessment. RESULTS: The 11 C-donepezil PET was successfully performed in 17 patients with iRBD and nine controls. Compared with controls, patients with iRBD showed a mean 7.65% reduction in neocortical 11 C-donepezil levels (P = 0.005). Bilateral superior temporal cortex, occipital cortex, cingulate cortex and dorsolateral prefrontal cortex showed the most significant reductions at voxel level. CONCLUSION: Reduced neocortical 11 C-donepezil binding in our patients indicates cholinergic denervation and suggests that the projections from the nucleus basalis of Meynert, which supplies cholinergic innervation to the neocortex, are dysfunctional in iRBD. Longitudinal studies will clarify if these changes are predictive of future cognitive impairment in these patients.

Surviving 10 years with deep brain stimulation for Parkinson's disease--a follow-up of 79 patients.

BACKGROUND AND PURPOSE: Deep brain stimulation (DBS) for severe Parkinson's disease (PD) outperforms the best medical treatment in controlling motor symptoms and improving quality of life. Nevertheless disease progression cannot be controlled, and the development of dementia over time is nearly inevitable, often resulting in nursing home placement. Ten-year survival, development of hallucinations, dementia and nursing home placement were examined and adverse events were assessed. METHOD: Patient files were scrutinized from baseline up to 10 years of treatment or death on all 79 PD patients treated with DBS of the subthalamic nucleus from 1998 to 2003 at Aarhus University Hospital. RESULTS: Twenty-four patients died during the follow-up period of 10 years. Age above 60 years at surgery increased mortality 2.3-fold (P = 0.04). Of the 55 surviving patients 29 (53%) were demented and 19 (35%) were in nursing homes. Average time from operation to dementia was 5.6 ± 2.9 years. Hallucinations and nursing home placement were associated with increased mortality. CONCLUSION: Survival of 70% after a mean of 25 years of PD including 10 years with DBS illustrates that this is a selected group of PD patients. The prevalence of dementia steadily increased after surgery as expected from disease progression and can be an early event. Compared with the few similar long-term studies, the present study presents a larger cohort followed at the same DBS center for a longer period of time and none was lost to follow-up, making conclusions more valid. The present findings are of significant prognostic help for the patient, caregiver and physician when treatment with DBS has to be decided.

Combined DaT imaging and olfactory testing for differentiating parkinsonian disorders.

OBJECTIVE: Dopamine transporter (DaT) imaging with single photon emission computed tomography (SPECT) detects loss of striatal dopaminergic innervation with very high sensitivity. It cannot readily distinguish idiopathic Parkinson's disease (iPD) and dementia with Lewy bodies (DLB) from atypical disorders (aPD). However, most iPD/DLB patients are hyposmic, whereas the majority of aPD patients were reported to have intact olfaction. For this reason, we conducted a longitudinal follow-up study to investigate the power of combined DaT imaging and olfactory testing to predict the final diagnosis of the patients. MATERIALS AND METHODS: A total of 129 patients received [123I]FP-CIT SPECT and olfactory testing at baseline assessment. Clinical follow-up 30 ± 12 months later was the diagnostic standard of truth. A normative dataset of 24 healthy controls was used for comparison. RESULTS: Baseline DaT imaging predicted a dopamine-deficient diagnosis with 98% sensitivity and 98% specificity. The combined DaT/olfactory testing correctly classified 91% of patients as iPD/DLB (PPV 91%). The PPV rose to 97% or greater in anosmic patients. In contrast, only 45% of aPD patients were categorised correctly by combined DaT/olfactory testing - mainly because of the presence of normosmic iPD patients. CONCLUSIONS: In patients with an abnormal DaT SPECT, hyposmia yields an a posteriori likelihood of iPD/DLB of > 90%. In contrast, a finding of normosmia only increases the a posteriori likelihood of aPD to approximately the 50%.

Comparing minimally invasive and proactive initial management of extremely preterm infants.

AIM: In 2005, we changed our minimally invasive departmental policy for infants born before 26 weeks of gestation to a proactive approach. This included structured guidelines as well as intubation and surfactant in the delivery room, if the parents agreed. The aim of this study was to evaluate the effect of this change of policy. METHOD: We compared the Ages and Stages Questionnaire (ASQ) scores, mortality rates and use of mechanical ventilation before (1999-2003) and after (2005-2011) the introduction of the new policy. RESULTS: Twenty-two per cent of 61 infants in the before group had an ASQ z-score of <-2 standard deviation at 18 months' corrected age, compared with 26% of 55 infants in the after group. Mortality decreased from 46% to 36% (p = 0.06) and the use of mechanical ventilation at any time during admission increased from 64% to 87% (p < 0.0001). CONCLUSION: We demonstrated that changing our policy to a proactive approach to the initial care of infants born before 26 weeks did not result in a major increase in psychomotor deficit. However, the use of mechanical ventilation increased significantly and survival tended to improve.

Clinical heterogeneity in Parkinson's disease revisited: a latent profile analysis.

OBJECTIVE: The heterogeneity of Parkinson's disease (PD) is increasingly recognized, and several attempts have been made to subclassify subjects on clinical or cognitive features. We explored the utility of latent profile analysis (LPA) as a means of classifying patients with PD on clinical features and test validity of these subclasses against neuropsychological data. METHODS: LPA utilizing clinical variables while controlling for age was applied to a cohort of 71 outpatients with PD. The resultant subgroups were validated via comparison to 30 control subjects on neuropsychological tests of executive, memory, and visuospatial functions. RESULTS: The LPA resulted in a three-class solution identifying a 'younger onset, mild motor impairment group', a 'moderate motor impairment group', and an 'old onset, fast progression group'. The groups were distinguishable on cognitive variables with the 'younger onset mild motor impairment subgroup' displaying deficits pertaining verbal acquisition, visuospatial construction, and set maintenance. The 'moderate motor impairment group' exhibited widespread cognitive impairment, and the 'old onset, fast disease progression group' had extensive cognitive impairment but outperformed the former group on verbal acquisition and visuospatial function. CONCLUSION: LPA holds promise in PD research as it uncovered three PD subtypes distinguished by motor symptoms and disease progression and validated by cognitive variables.

MRI verified STN stimulation site--gait improvement and clinical outcome.

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is effective in alleviating Parkinson's disease (PD) symptoms (tremor, rigidity and bradykinesia) and may improve gait and postural impairment associated with the disease. However, improvement of gait is not always as predictable as the clinical outcome. This may relate to the type of gait impairment or localization of the active DBS contact. METHODS: The active contact was visualized on peri-operative magnetic resonance imaging in 22 patients with idiopathic PD, consecutively treated with bilateral STN DBS. Stimulation site was grouped as either in the dorsal/ventral STN or medial/lateral hereof and anterior/posterior STN or medial/lateral hereof. The localization was compared with relative improvement of clinical outcome (UPDRS-III). In 10 patients, quantitative gait analyses were performed, and the improvement in gait performance was compared with stimulation site in the STN. RESULTS: Of 44 active contacts, 77% were inside the nucleus, 23% were medial hereof. Stimulation of the dorsal half improved UPDRS-III significantly more than ventral STN DBS (P = 0.02). However, there were no differences between anterior and posterior stimulation in the dorsal STN. Step velocity and length improved significantly more with dorsal stimulation compared with ventral stimulation (P = 0.03 and P = 0.02). Balance during gait was also more improved with dorsal stimulation compared with ventral stimulation. CONCLUSIONS: Deep brain stimulation of the dorsal STN is superior to stimulation of the ventral STN. Possible different effects of stimulation inside the nucleus underline the need for exact knowledge of the active stimulation site position to target the most effective area.

A deformation-based morphometry study of patients with early-stage Parkinson's disease.

BACKGROUND AND PURPOSE: Previous volumetric magnetic resonance imaging (MRI) studies of Parkinson's disease (PD) utilized primarily voxel-based morphometry (VBM), and investigated mostly patients with moderate- to late-stage disease. We now use deformation-based morphometry (DBM), a method purported to be more sensitive than VBM, to test for atrophy in patients with early-stage PD. METHODS: T1-weighted MRI images from 24 early-stage PD patients and 26 age-matched normal control subjects were compared using DBM. Two separate studies were conducted, where two minimally-biased nonlinear intensity-average were created; one for all subjects and another for just the PD patients. The DBM technique creates an average population-based MRI-average in an iterative hierarchical fashion. The nonlinear transformations estimated to match each subject to the MRI-average were then analysed. RESULTS: The DBM comparison between patients and controls revealed significant contraction in the left cerebellum, and non-significant trends towards frontal, temporal and cingulate sulcal expansions with frontal and temporal white matter contractions. Within the patient group, the unified PD rating scores were highly correlated with local expansions in or near sulci bordering on frontal and temporal cortex. CONCLUSION: Our results suggest that DBM could be a sensitive method for detecting morphological changes in early-stage PD.

Household dampness and microbial exposure related to allergy and respiratory health in Danish adults.

Background: Indoor dampness has consistently been associated with respiratory symptoms and exacerbations. The causal mechanisms may involve increased microbial exposures. However, the evidence regarding the influence of indoor microbial exposures under damp- and non-damp conditions on the risk of asthma and allergy has been inconclusive. Objective: The aim of this study was to investigate the association between dampness and microbial exposure with allergy and respiratory health in Danish adults using a cross-sectional design. Methods: From 1,866 participants of the Health2006 cohort, we selected three non-overlapping groups: 196 at random, 107 with confirmed atopy, and 99 without atopy. Bedroom dust was sampled using electrostatic dust fall collectors and analysed for endotoxin, ß-(1,3)-D-glucan, 19 microbial species or groups, and total fungal load. Household moisture-related problems and asthma were self-reported by questionnaire. Atopy was determined by skin-prick-testing and lung function was measured by spirometry. Results: Household moisture damage was positively associated with asthma outcomes, although this was statistically significant only in atopics for self-reported asthma (odds ratio (OR) 3.52; 95%CI 1.01-12.7). Mould odor was positively associated with wheezing (OR 6.05; 95%CI 1.19-30.7) in atopics. Inconsistent associations were found for individual microbial exposures and health outcomes. Inverse associations were observed between microbial diversity and rhinitis in the random sample and both doctor-diagnosed and self-reported asthma in non-atopics. Conclusions: In conclusion, our findings suggest that household moisture damage may increase the risk of asthma and wheeze with mould odor in atopics. In addition, asthma and allergy may be affected by the indoor microbial composition in urban domestic environments. Further studies are needed to identify and understand the causal agents and underlying mechanisms behind the potential effects of environmental microbial exposure on human health.

Jugular venous pooling during lowering of the head affects blood pressure of the anesthetized giraffe.

How blood flow and pressure to the giraffe's brain are regulated when drinking remains debated. We measured simultaneous blood flow, pressure, and cross-sectional area in the carotid artery and jugular vein of five anesthetized and spontaneously breathing giraffes. The giraffes were suspended in the upright position so that we could lower the head. In the upright position, mean arterial pressure (MAP) was 193 +/- 11 mmHg (mean +/- SE), carotid flow was 0.7 +/- 0.2 l/min, and carotid cross-sectional area was 0.85 +/- 0.04 cm(2). Central venous pressure (CVP) was 4 +/- 2 mmHg, jugular flow was 0.7 +/- 0.2 l/min, and jugular cross-sectional area was 0.14 +/- 0.04 cm(2) (n = 4). Carotid arterial and jugular venous pressures at head level were 118 +/- 9 and -7 +/- 4 mmHg, respectively. When the head was lowered, MAP decreased to 131 +/- 13 mmHg, while carotid cross-sectional area and flow remained unchanged. Cardiac output was reduced by 30%, CVP decreased to -1 +/- 2 mmHg (P < 0.01), and jugular flow ceased as the jugular cross-sectional area increased to 3.2 +/- 0.6 cm(2) (P < 0.01), corresponding to accumulation of approximately 1.2 l of blood in the veins. When the head was raised, the jugular veins collapsed and blood was returned to the central circulation, and CVP and cardiac output were restored. The results demonstrate that in the upright-positioned, anesthetized giraffe cerebral blood flow is governed by arterial pressure without support of a siphon mechanism and that when the head is lowered, blood accumulates in the vein, affecting MAP.

Heart valve disease associated with treatment with ergot-derived dopamine agonists: a clinical and echocardiographic study of patients with Parkinson's disease.

OBJECTIVE: To elucidate the association between treatment with ergot-derived dopamine agonists (EDDA) and valvular abnormalities amongst patients with idiopathic Parkinson's disease (IPD) and secondly, to analyse the yield of clinical screening for valvular heart disease. DESIGN: A cross-sectional controlled study. SETTING: The cohort of IPD patients treated in the outpatient clinic, Department of Neurology, Aarhus University Hospital, Denmark. SUBJECTS: A total of 138 IPD patients [median age 64 (39-87) years, 62% men] treated with either EDDA (n = 85) or non-EDDA (n = 53) for at least 6 months. Interventions. Patients were screened for valvular heart disease by clinical means and by examiner-blinded echocardiography. Main outcome measure was valvular regurgitation revealed by echocardiography. RESULTS: Severe aortic regurgitation (n = 4) or moderate aortic (n = 12), mitral (n = 3) or tricuspidal valve regurgitation (n = 5) was found in 22 EDDA patients (25.9%). Two patients had coexistent moderate mitral and tricuspid valvular regurgitation. Two non-EDDA patients had moderate valve insufficiency (3.8%, P < 0.05). The adjusted relative risk for at least moderate valve insufficiency in the EDDA patients was 7.2% (P < 0.05). The sensitivity of detecting at least moderate valvular disease by cardiac murmur, dyspnoea, or the heart failure marker NT-proBNP (natriuretic peptide) was 62% for the neurologists and 93% for the cardiologist but with equally low specificity (30-35%). CONCLUSION: EDDA was associated with a clinically important and statistically significant risk of at least moderate valve regurgitation. Clinical screening for valve disease was inadequate and it seems advisable to offer EDDA patients control with echocardiography.

Clinical aspects of bowel symptoms in Parkinson's disease.

BACKGROUND: The clinical importance of bowel symptoms in Parkinson's disease (PD) remains to be described in detail. METHODS: A 33-item questionnaire including background parameters, the Cleveland Constipation Score (CCS), and items from the Neurogenic Bowel Dysfunction score was sent to 468 PD patients. Results were compared to a control group (CG) (n = 45). A CCS of at least 15 was used to define severe constipation. RESULTS: Four hundred and sixteen subjects (89%) responded. Median CSS was only 4 (range 0-21) in PD and 2 (range 0-13) in the CG (P < 0.05). Severe constipation was found in 7% with PD and 0% in the CG (P < 0.05). Incomplete emptying at defecation, need for assisted defecation and use of oral laxatives was reported more frequently by PD patients than by the CG (all P < 0.05). The severity of PD was associated with assisted defecation (P < 0.001), unsuccessful attempts at defecation (P < 0.001), incomplete emptying at defecation (P < 0.05), and the CCS (P < 0.01). Time since diagnosis was associated with infrequent defecation (P < 0.0001) and the CCS (P < 0.05). The use of levodopa was associated with less unsuccessful attempts at defecation (P < 0.05). CONCLUSION: Most patients with PD only have minor constipation-related symptoms. However, severe constipation is associated with time since diagnosis and severity of disease.

Effect of memantine on CBF and CMRO2 in patients with early Parkinson's disease.

OBJECTIVES: Parkinson's disease (PD) may be associated with increased energy metabolism in overactive regions of the basal ganglia. Therefore, we hypothesized that treatment with the N-methyl-d-aspartate receptor (NMDAR) antagonist memantine would decrease regional cerebral blood flow (rCBF) and oxygen metabolism in the basal ganglia of patients with early-stage PD. METHODS: Quantitative positron emission tomography (PET) recordings were obtained with 15O]water and 15O]oxygen in 10 patients, scanned first in a baseline condition, and again 6 weeks after treatment with a daily dose of 20 mg memantine. Dynamic PET data were analyzed using volume of interest and voxel-based approaches. RESULTS: The treatment evoked rCBF decreases in basal ganglia, and in several frontal cortical areas. The regional cerebral metabolic rate of oxygen (rCMRO2) did not decrease in any of the a priori defined regions, and consequently the oxygen extraction fraction was increased in these regions. Two peaks of significantly decreased rCMRO2 were detected near the frontal poles in both hemispheres, using a posteriori voxel-based analysis. CONCLUSIONS: Although we did not find the predicted decrease in basal ganglia oxygen consumption, our data suggest that treatment with memantine actively modulates neuronal activity and/or hemodynamic response in basal ganglia of PD patients. This finding may be relevant to the putative neuroprotective properties of NMDAR antagonists.

Chronic subthalamic high-frequency deep brain stimulation in Parkinson's disease--a histopathological study.

This study describes the pathological findings in the brain of a patient with Parkinson's disease (PD) treated with bilateral subthalamic high-frequency deep brain stimulation (STN DBS) for 29 months prior to death. After routine neuropathological examination, tissue blocks containing the electrode tracts, the subthalamic nucleus (STN), the substantia nigra and the pre-frontal cortex were paraffin embedded and cut into 5-microm-thick serial sections and stained with several conventional staining methods and immunohistochemistry. Bilateral nigral depigmentation, cell loss and Lewy body formation confirmed the diagnosis of PD. Microscopic evaluation furthermore confirmed the location of the electrodes in the STN. The electrode tracts were surrounded by a 150-microm-wide glial fibrillary acidic protein (GFAP)-positive capsule consisting of a thin collagen layer lining the lumen of the tract, whilst an area with few cells and axons constituted the capsule wall towards the surrounding normal brain tissue. The brain tissue appeared normal outside the capsule boundaries with no difference in areas of stimulation compared with areas of no stimulation. Our results correspond with previous studies performed after fewer months of STN DBS and indicate mild histopathological changes in the vicinity of the electrode tract, appearing to result from the electrode placement and not from the electrical stimulation.

The giraffe kidney tolerates high arterial blood pressure by high renal interstitial pressure and low glomerular filtration rate.

BACKGROUND: The tallest animal on earth, the giraffe (Giraffa camelopardalis) is endowed with a mean arterial blood pressure (MAP) twice that of other mammals. The kidneys reside at heart level and show no sign of hypertension-related damage. We hypothesized that a species-specific evolutionary adaption in the giraffe kidney allows normal for size renal haemodynamics and glomerular filtration rate (GFR) despite a MAP double that of other mammals. METHODS: Fourteen anaesthetized giraffes were instrumented with vascular and bladder catheters to measure glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Renal interstitial hydrostatic pressure (RIHP) was assessed by inserting a needle into the medullary parenchyma. Doppler ultrasound measurements provided renal artery resistive index (RI). Hormone concentrations as well as biomechanical, structural and histological characteristics of vascular and renal tissues were determined. RESULTS: GFR averaged 342 ± 99 mL min(-1) and ERPF 1252 ± 305 mL min(-1) . RIHP varied between 45 and 140 mmHg. Renal pelvic pressure was 39 ± 2 mmHg and renal venous pressure 32 ± 4 mmHg. A valve-like structure at the junction of the renal and vena cava generated a pressure drop of 12 ± 2 mmHg. RI was 0.27. The renal capsule was durable with a calculated burst pressure of 600 mmHg. Plasma renin and AngII were 2.6 ± 0.5 mIU L(-1) and 9.1 ± 1.5 pg mL(-1) respectively. CONCLUSION: In giraffes, GFR, ERPF and RI appear much lower than expected based on body mass. A strong renal capsule supports a RIHP, which is >10-fold that of other mammals effectively reducing the net filtration pressure and protecting against the high MAP.

Tyrosine hydroxylase and acetylcholinesterase in the domestic pig mesencephalon: an immunocytochemical and histochemical study.

The mesencephalon of the young domestic pig was studied by tyrosine hydroxylase (TH) immunocytochemistry and acetylcholinesterase (AChE) histochemistry with focus on the substantia nigra (SN), the ventral tegmental area (VTA), and related areas. The purpose was to obtain information on the organization of the mesencephalic, TH immunoreactive (TH-i), and dopaminergic areas of the pig, in order to provide the necessary background for the possible use of the pig as an alternative large animal experimental model for research on Parkinson's disease, including the use of encapsulated pig dopaminergic neurons for intracerebral xenotransplantation. Significant findings in the pig, compared to observations in other species, included the presence of prominent bundles of TH-i dendrites passing in a dorsoventral direction from pars compacta into pars reticulata at middle and caudal levels of the SN, and the presence of a distinct TH-i substantia nigra pars lateralis (SNL). Caudally in the pig mesencephalon, the retrorubral field (RRF) was found to be very extensive. The view of the RRF, SN, and VTA as parts of the same integrated system was indicated by the crisscrossing of TH-i dendrites at the transitions between these areas. Estimation of the number of TH-i neurons in the SN and the VTA showed that these nuclei were of equal size in the pig. Further, it was found that TH-i nerve cells were present in the midline between the VTA in the interfascicular and rostral linear groups. TH-i nerve cells were also present in the otherwise serotoninergic dorsal raphe nuclei, just as other TH-i cells formed a perirubral cell group. AChE-positive neurons were present in both SN and VTA, and appeared to have the same size and morphology as the TH-i neurons in these areas. Within both nuclei, there were local differences in the AChE staining density, but perhaps more significantly were some marked differences in the structure of the AChE-positive neuropil of the two areas. We anticipate that the present description of the cellular organization of the TH-i dopaminergic areas in the domestic pig ventral mesencephalon will be useful for the development of a nonprimate, large animal, experimental model of Parkinson's disease.

Estimation of the number of somatostatin neurons in the striatum: an in situ hybridization study using the optical fractionator method.

Somatostatin-containing neurons of the striatum constitute fewer than 5% of the total neuronal population. Their involvement in the feedforward inhibition of the spiny projection neurons, the modulation of other interneurons, and the regulation of regional blood flow indicates that this small population of neurons plays an important role in the processing of information in the striatum. As a first step in developing a quantitative structural framework within which a more rigorous analysis can be made of the functional circuitry of the striatum, we used modern unbiased stereological techniques to make estimates of the total number of neurons expressing mRNA for somatostatin in the striatum of rats. The strategy developed involved the application of the optical fractionator technique to relatively thick tissue sections that were hybridized in situ with a relatively short oligonucleotide probe conjugated to a nonradioactive reporter molecule. The approach is generally applicable to other subpopulations of in situ hybridized cells in other parts of the brain and can provide a link between molecular neurobiology and stereology. The mean total number of neurons on one side of the striatum was estimated to be 21,300. An analysis of the sampling scheme indicated that counting no more than 200 neurons in a systematic sample of not more than 15 sections per individual results in an estimate with a precision that is more than sufficient for comparative and experimental studies. The issues that must be considered when analyzing in situ hybridized tissue with modern stereological methods, the interpretive caveats inherent in the resulting data, and the unique perspectives provided by data like that presented here for striatal somatostatin neurons are discussed.

Organotypic slice cultures of the rat striatum--I. A histochemical and immunocytochemical study of acetylcholinesterase, choline acetyltransferase, glutamate decarboxylase and GABA.

Slices of striatal tissue from newborn to eight-day-old rats were cultured for six to 47 days. Cholinergic neurons and fibres were then visualized by histochemical staining for acetylcholinesterase or immunocytochemical staining for choline acetyltransferase. GABA-containing neurons and fibres were visualized by immunocytochemical staining for glutamate decarboxylase or GABA. Corresponding to the normal postnatal development in vivo, acetylcholinesterase staining of the striatal tissue progressed from a "patchy" distribution in the six to 14 days old cultures to an almost even distribution of high acetylcholinesterase activity after 18-27 days. Extrinsic afferents were accordingly not necessary for the maintenance of a patch-matrix-like, acetylcholinesterase distribution during the first one to two weeks in culture, just as a subsequent, normal developmental change of the acetylcholinesterase staining pattern into a more homogeneous distribution also occurred without such afferents. Cholinergic, choline acetyltransferase-immunoreactive neurons were evenly distributed within the cultured striatal tissue, like in vivo, but the density of the neurons appeared to be higher in the cultures. The neurons had a morphology corresponding to the "classical", large-sized, aspiny, cholinergic interneurons in the adult rat striatum. Glutamate decarboxylase-immunoreactive and GABA-immunoreactive neurons were either lightly or darkly stained and of medium size, but some large, lightly stained glutamate decarboxylase-immunoreactive and GABA-immunoreactive neurons were also found. The difference in staining density among the medium-sized cells was observed with both antisera and hence provide evidence for the existence of two populations of medium-sized GABAergic neurons, which in vivo are intensely stained interneurons and more weakly stained, spiny projection neurons. Fibres stained better for glutamate decarboxylase than for GABA and outgrowth of glutamate decarboxylase-immunoreactive nerve fibres from the striatal slice cultures onto the coverslip was often observed. The presence at all culture periods of "protospines" on cell bodies and proximal dendrites of some glutamate decarboxylase-immunoreactive, and in particular some GABA-immunoreactive neurons, suggested that at least some developmental characteristics might be maintained for extended periods in culture. In several cultures, groups of small GABA-immunoreactive cells were observed. Similar groups were also found by staining for glutamate decarboxylase, but a smaller proportion of the cells were then positively stained. In view of their immature appearance with few or no processes, the known presence of GABA in neuroblast-like cells, and the recent demonstration of neuronal and glial progenitor cells in the adult mouse striatum, the small cells might belong to a population of undifferentiated cells surviving in the slice cultures.(ABSTRACT TRUNCATED AT 400 WORDS)

The relationship between oral dyskinesias produced by long-term haloperidol treatment, the density of striatal preproenkephalin messenger RNA and enkephalin peptide, and the number of striatal neurons expressing preproenkephalin messenger RNA in rats.

Neuroleptic-induced oral dyskinesias in rats, a putative analogue to human tardive dyskinesia, may be due to excitotoxic degeneration within the striatum. Haloperidol treatment for 34 weeks increased the optical density of preproenkephalin messenger RNA in individual striatal neurons and enkephalin peptide in the neuropil, regardless of the level of oral dyskinesia produced. However, using unbiased stereological methods, an increased number of striatal neurons expressing preproenkephalin messenger RNA was observed only in rats that did not develop pronounced oral dyskinesias during haloperidol treatment. Said in another manner, the haloperidol-treated animals that developed pronounced oral dyskinesias, failed to produce an increase in the number of neurons expressing preproenkephalin messenger RNA. These results indicate that the mechanism by which neuroleptics induce oral dyskinesias in rats, and perhaps tardive dyskinesia in humans, involves a functional disturbance or even damage to a subpopulation of enkephalinergic neurons in the striatum.

Reduced number of striatal neurons expressing preprosomatostatin mRNA in rats with oral dyskinesias after long-term haloperidol administration.

Neuroleptic-induced oral dyskinesia in rats, a putative analogue to human tardive dyskinesia, may be due to degeneration within the striatum. Using unbiased stereological methods, a decreased number of striatal neurons expressing preprosomatostatin mRNA was observed only in rats that developed pronounced oral dyskinesias after 30 weeks of haloperidol administration. The amount of preprosomatostatin mRNA in each striatal neuron, measured in terms of optical densities of individual neurons, was not affected by haloperidol. A tendency toward a reduction in the number of NADPH-diaphorase positive neurons was observed in rats receiving haloperidol. These results indicate that the mechanism by which neuroleptics induce oral dyskinesias in rats, and perhaps tardive dyskinesia in humans, involves a functional disruption and possibly damage of a subpopulation of interneurons in the striatum.

Zinc-containing neurons are distinct from GABAergic neurons in the telencephalon of the rat.

We used a double-labeling protocol that combined the silver amplification of endogenous zinc with routine immunocytochemistry to determine if telencephalic neurons that exhibit GABA-, calbindin- or parvalbumin-like immunoreactivity give rise to zinc-containing boutons. We did not observe telencephalic neurons double-labeled for zinc and GABA or parvalbumin. Zinc and strong calbindin immunoreactivity were colocalized in hippocampal CA1 pyramidal cells and dentate granule cells. Other strongly calbindin-immunoreactive neurons of the telencephalon were never double-labeled. We conclude that GABAergic cells do not contain histochemically reactive zinc and, therefore, are unlikely to use this pool of zinc as a neuromodulator. This observation does not support an in vivo significance of the modulation of GABA receptors by zinc such as has been observed in vitro. In CA1 of the hippocampus, we observed the histochemical label for zinc in all visibly calbindin-immunoreactive pyramidal cells and vice versa. Thus, two markers define a subpopulation of hippocampal pyramidal cells.