Cholinergic Structures Research Articles

Cholinergic profiles in the Goettingen miniature pig (Sus scrofa domesticus) brain.

Central cholinergic structures within the brain of the even-toed hoofed Goettingen miniature domestic pig (Sus scrofa domesticus) were evaluated by immunohistochemical visualization of choline acetyltransferase (ChAT) and the low-affinity neurotrophin receptor, p75NTR . ChAT-immunoreactive (-ir) perikarya were seen in the olfactory tubercle, striatum, medial septal nucleus, vertical and horizontal limbs of the diagonal band of Broca, and the nucleus basalis of Meynert, medial habenular nucleus, zona incerta, neurosecretory arcuate nucleus, cranial motor nuclei III and IV, Edinger-Westphal nucleus, parabigeminal nucleus, pedunculopontine nucleus, and laterodorsal tegmental nucleus. Cholinergic ChAT-ir neurons were also found within transitional cortical areas (insular, cingulate, and piriform cortices) and hippocampus proper. ChAT-ir fibers were seen throughout the dentate gyrus and hippocampus, in the mediodorsal, laterodorsal, anteroventral, and parateanial thalamic nuclei, the fasciculus retroflexus of Meynert, basolateral and basomedial amygdaloid nuclei, anterior pretectal and interpeduncular nuclei, as well as select laminae of the superior colliculus. Double immunofluorescence demonstrated that virtually all ChAT-ir basal forebrain neurons were also p75NTR -positive. The present findings indicate that the central cholinergic system in the miniature pig is similar to other mammalian species. Therefore, the miniature pig may be an appropriate animal model for preclinical studies of neurodegenerative diseases where the cholinergic system is compromised. J. Comp. Neurol. 525:553-573, 2017. © 2016 Wiley Periodicals, Inc.

Вплив блокування м1-холінорецепторів асоціативної кори дорослих щурів на автономну регуляцію серцевого ритму при гіпоксичному впливі

<p>Резюме. Моделювання атмосферної гіпоксії в експерименті на щурах дозволяє більш детально дослідити участь речовин медіаторної дії у формуванні адаптації регуляторних систем мозку до гіпоксичного впливу. Метою експерименту було виявити функціональні наслідки блокування м<sub>1</sub>-холінорецепторів в асоціативній корі дорослих щурів у гіпоксичному середовищі за умов зниженого атмосферного тиску. За умов експериментальної гіпоксії спостерігали функціональну перебудову включення холінергічних структур до механізмів автономного контролю серцевого ритму. Інкубація дорослих щурів у гіпоксичному середовищі за умов зниженого атмосферного тиску, аналогічному природним умовам ІІІ типу погоди, призводить до активації холінергічної регуляції серцевого ритму.</p><p> </p><p>Ключові слова: блокування м<sub>1</sub>-холінорецепторів, асоціативна кора, знижений атмосферний тиск.</p>

Extrinsic Sources of Cholinergic Innervation of the Striatal Complex: A Whole-Brain Mapping Analysis.

Acetylcholine in the striatal complex plays an important role in normal behavior and is affected in a number of neurological disorders. Although early studies suggested that acetylcholine in the striatum (STR) is derived almost exclusively from cholinergic interneurons (CIN), recent axonal mapping studies using conditional anterograde tracing have revealed the existence of a prominent direct cholinergic pathway from the pedunculopontine and laterodorsal tegmental nuclei to the dorsal striatum and nucleus accumbens. The identification of the importance of this pathway is essential for creating a complete model of cholinergic modulation in the striatum, and it opens the question as to whether other populations of cholinergic neurons may also contribute to such modulation. Here, using novel viral tracing technologies based on phenotype-specific fluorescent reporter expression in combination with retrograde tracing, we aimed to define other sources of cholinergic innervation of the striatum. Systematic mapping of the projections of all cholinergic structures in the brain (Ch1 to Ch8) by means of conditional tracing of cholinergic axons, revealed that the only extrinsic source of cholinergic innervation arises in the brainstem pedunculopontine and laterodorsal tegmental nuclei. Our results thus place the pedunculopontine and laterodorsal nuclei in a key and exclusive position to provide extrinsic cholinergic modulation of the activity of the striatal systems.

Heterogeneous choline acetyltransferase staining in cholinergic neurons

We studied the features of choline acetyltransferase (ChAT) distribution in cholinergic structures of the central and peripheral nervous systems; specifically in the spinal cord and dorsal root ganglion (DRG) of embryo (E20), newborn, or adult rats using a goat polyclonal antibody. We found that this anti-ChAT antibody selectively labels both central and peripheral cholinergic structures. We observed cholinergic neurons with weak immunoreactivity. We demonstrated that at all stages of ontogeny that we studied, four groups of cholinergic neurons occurred in the cervical part of the spinal cord, viz., the small neurons of the dorsal horns, neurons of Rexed’s lamina X, neurons of the area of Rexed’s laminae VI–VII, and cells of the ventral horns. Interneurons of Rexed’s laminae VI–VII exhibited maximum ChAT reactivity as compared to other groups of cholinergic neurons of the spinal cord at all developmental stages we studied. We found an increase in the number of immunopositive cells of lamina X from E20 stage to the early postnatal and mature stages. In the peripheral cholinergic structures, i.e., the DRG, of the rat, all neurons expressed ChAT at all stages of ontogeny.

Structural and functional neuroimaging in patients with Parkinson's disease and visual hallucinations: A critical review.

Patients with Parkinson's disease (PD) may develop various non-motor symptoms (NMS) during the course of the illness and psychosis is one of the common NMS of PD. Visual hallucinations (VH) are the most common manifestation of psychosis in PD. The exact pathogenesis of VH in patients with PD is not clearly understood. Presence of VH has been described to be associated with rapid cognitive decline and increased nursing home placements in PD patients. A large number of structural and functional neuroimaging studies have been conducted to understand the cerebral basis of VH in PD. Structural imaging studies (Voxel Based Morphometry) have reported grey matter atrophy in multiple regions of the brain such as primary visual cortex, visual association cortex, limbic regions, cholinergic structures such as pedunculopontine nucleus and substantia innominata, which conclude possible alterations of brain regions associated with functions such as visuospatial-perception, attention control and memory. Most functional neuroimaging studies (functional MRI, positron emission tomography and single photon emission computerized tomography) have reported altered activation, blood flow, or reduced metabolism in both dorsal and ventral visual pathways, which probably indicates an alteration in the normal bottom-top visual processing and the presence of an aberrant top-down visual processing. This review critically analyzes the published studies on the structural and functional neuroimaging in PD patients with VH.

Comparative study of cholinergic structures of the striatum of human and rat using choline acetyltransferase immunocytochemical reaction

Comparative study of cholinergic structures of the striatum of human and rat using choline acetyltransferase immunocytochemical reaction

Neuronal and nonneuronal cholinergic structures in the mouse gastrointestinal tract and spleen.

Accumulating evidence demonstrates that acetylcholine can directly modulate immune function in peripheral tissues including the spleen and gastrointestinal tract. However, the anatomical relationships between the peripheral cholinergic system and immune cells located in these lymphoid tissues remain unclear due to inherent technical difficulties with currently available neuroanatomical methods. In this study, mice with specific expression of the tdTomato fluorescent protein in choline acetyltransferase (ChAT)-expressing cells were used to label preganglionic and postganglionic cholinergic neurons and their projections to lymphoid tissues. Notably, our anatomical observations revealed an abundant innervation in the intestinal lamina propria of the entire gastrointestinal tract principally originating from cholinergic enteric neurons. The aforementioned innervation frequently approached macrophages, plasma cells, and lymphocytes located in the lamina propria and, to a lesser extent, lymphocytes in the interfollicular areas of Peyer's patches. In addition to the above innervation, we observed labeled epithelial cells in the gallbladder and lower intestines, as well as Microfold cells and T-cells within Peyer's patches. In contrast, we found only a sparse innervation in the spleen consisting of neuronal fibers of spinal origin present around arterioles and in lymphocyte-containing areas of the white pulp. Lastly, a small population of ChAT-expressing lymphocytes was identified in the spleen including both T- and B-cells. In summary, this study describes the variety of cholinergic neuronal and nonneuronal cells in a position to modulate gastrointestinal and splenic immunity in the mouse.

Thalamic volume and related visual recognition are associated with freezing of gait in non-demented patients with Parkinson's disease

BackgroundThe pathophysiology of freezing of gait (FOG) in non-demented Parkinson's disease (PD) patients remains poorly understood. Recent studies have suggested that neurochemical alterations in the cholinergic systems play a role in the development of FOG. Here, we evaluated the association between subcortical cholinergic structures and FOG in patients with non-demented PD. MethodsWe recruited 46 non-demented patients with PD, categorized into PD with (n = 16) and without FOG (n = 30) groups. We performed neuropsychological test, region-of-interest-based volumetric analysis of the substantia innominata (SI) and automatic analysis of subcortical brain structures using a computerized segmentation procedure. ResultsThe comprehensive neuropsychological assessment showed that PD patients with FOG had lower cognitive performance in the frontal executive and visual-related functions compared with those without freezing of gait. The normalized SI volume did not differ significantly between the two groups (1.65 ± 0.18 vs. 1.68 ± 0.31). The automatic analysis of subcortical structures revealed that the thalamic volumes were significantly reduced in PD patients with FOG compared with those without FOG after adjusting for age, sex, disease duration, the Unified PD Rating Scale scores and total intracranial volume (left: 6.71 vs. 7.16 cm3, p = 0.029, right: 6.47 vs. 6.91 cm3, p = 0.026). Multiple linear regression analysis revealed that thalamic volume showed significant positive correlations with visual recognition memory (left: β = 0.441, p = 0.037, right: β = 0.498, p = 0.04). ConclusionsThese data suggest that thalamic volume and related visual recognition, rather than the cortical cholinergic system arising from the SI, may be a major contributor to the development of freezing of gait in non-demented patients with PD.

Organization of the innervation of the oesophagus and stomach in chinchilla (Chinchilla laniger, Molina)

Using the histochemical and histological techniques the morphology and topography of the autonomic plexuses of the oesophagus and stomach in chinchilla (Chinchilla laniger) was investigated. AChE-positive and adrenergic structures in the myenteric and submucosal plexus were observed. According to the results the cholinergic structures were formed by the different in shape network meshes, various size of the neurons agglomerations and nerve fibres. Adrenergic fibres were found. Density of these structures varied in different parts of the investigated organs. This study is the first attempt to localize the intramural autonomic plexuses in this species.

Exploratory analysis of neuropsychological and neuroanatomical correlates of progressive mild cognitive impairment in Parkinson's disease

BackgroundParkinson's disease with mild cognitive impairment (PD-MCI) is a heterogeneous entity in terms of cognitive profiles and conversion to dementia. However, the risk factors for ongoing cognitive decline in patients...

Immunohistochemical localization of two types of choline acetyltransferase in neurons and sensory cells of the octopus arm

Cholinergic structures in the arm of the cephalopod Octopus vulgaris were studied by immunohistochemistry using specific antisera for two types (common and peripheral) of acetylcholine synthetic enzyme choline acetyltransferase (ChAT): antiserum raised against the rat common type ChAT (cChAT), which is cross-reactive with molluscan cChAT, and antiserum raised against the rat peripheral type ChAT (pChAT), which has been used to delineate peripheral cholinergic structures in vertebrates, but not previously in invertebrates. Western blot analysis of octopus extracts revealed a single pChAT-positive band, suggesting that pChAT antiserum is cross-reactive with an octopus counterpart of rat pChAT. In immunohistochemistry, only neuronal structures of the octopus arm were stained by cChAT and pChAT antisera, although the pattern of distribution clearly differed between the two antisera. cChAT-positive varicose nerve fibers were observed in both the cerebrobrachial tract and neuropil of the axial nerve cord, while pChAT-positive varicose fibers were detected only in the neuropil of the axial nerve cord. After epitope retrieval, pChAT-positive neuronal cells and their processes became visible in all ganglia of the arm, including the axial and intramuscular nerve cords, and in ganglia of suckers. Moreover, pChAT-positive structures also became detectable in nerve fibers connecting the different ganglia, in smooth nerve fibers among muscle layers and dermal connective tissues, and in sensory cells of the suckers. These results suggest that the octopus arm has two types of cholinergic nerves: cChAT-positive nerves from brain ganglia and pChAT-positive nerves that are intrinsic to the arm.

The summary on non-reactivation cholinergic properties of oxime reactivators: the interaction with muscarinic and nicotinic receptors

Organophosphorus inhibitors (OP) of acetylcholinesterase (AChE) represent a group of highly toxic compounds. The treatment of OP intoxication is, however, insufficiently ensured. Currently, two main categories of drugs-anticholinergics and oxime reactivators- are employed as antidotes. Oximes have been reported to act at several levels of the cholinergic transmission, and among the non-reactivation effects, the interaction with cholinergic receptors stands out. This review addresses issues correlated with non-reactivating effects of oxime reactivators with a special focus on the muscarinic and nicotinic receptors, but involvement of other cholinergic structures such as AChE and choline uptake carriers are discussed too. It can be concluded that the oxime reactivators show a variation in their antagonistic effect on the muscarinic and nicotinic receptors, which is likely to be of significance in the treatment of OP poisoning. In vitro data reported oximes to exert higher efficacy on the muscarinic M2 subtype than on the AChE. However, this effect seemed to be subtype specific since the antagonistic M3 effect was lower. Also, and importantly, the antimuscarinic effect was larger than that on nicotinic receptors. Even though atropine showed a much higher muscarinic antagonism, it is supposed that non-reactivation properties of oxime reactivators play a significant role in the treatment of OP poisoning.

Immunolocalization of choline acetyltransferase of common type in the central brain mass of Octopus vulgaris.

Acetylcholine, the first neurotransmitter to be identified in the vertebrate frog, is widely distributed among the animal kingdom. The presence of a large amount of acetylcholine in the nervous system of cephalopods is well known from several biochemical and physiological studies. However, little is known about the precise distribution of cholinergic structures due to a lack of a suitable histochemical technique for detecting acetylcholine. The most reliable method to visualize the cholinergic neurons is the immunohistochemical localization of the enzyme choline acetyltransferase, the synthetic enzyme of acetylcholine. Following our previous study on the distribution patterns of cholinergic neurons in the Octopus vulgaris visual system, using a novel antibody that recognizes choline acetyltransferase of the common type (cChAT), now we extend our investigation on the octopus central brain mass. When applied on sections of octopus central ganglia, immunoreactivity for cChAT was detected in cell bodies of all central brain mass lobes with the notable exception of the subfrontal and subvertical lobes. Positive varicosed nerves fibers where observed in the neuropil of all central brain mass lobes.

Postnatal development of nitrergic and cholinergic structures in rat spinal cord.

Nitric oxide (NO) is known to be a freely diffusible gaseous neurotransmitter that is not requiring synaptic connection to exert its effects. Nitric oxide synthase (NOS), the enzyme responsible for NO synthesis can be visualised by nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry. Other neurotransmitter is a classical neurotransmitter acetylcholine (ACh), regulated by enzyme acetylcholinesterase (AChE) that hydrolyses the acetylcholine after its releasing. This work is presenting results of histochemical study of the NADPH-d and AChE expression (nitrergic and cholinergic neurons) in the spinal cord (SC) during various periods in its development. Specimens from Wistar rat pups in the age ranging from 1st to 21st postnatal days (P1-P21) have been compared with those of adult rats (P90). Transverse sections of the SC were evaluated by light microscope. In adults, the NADPH-d positivity was detectable in the neurons of superficial and deep layers of the dorsal horn, pericentral area and in the area of preganglionic autonomic nuclei. AChE positive structures were seen in the same locations as previous ones with the exception of two locations: in superficial layers of the dorsal horn AChE staining was absent, while in the ventral horn the groups of AChE positive motoneurons were found. At the perinatal period both NADPH-d and AChE positive neurons were stained from slight to moderate intensity only. During later developmental periods the staining gradually increased and achieved adult level of intensity on the day P21. Our results confirmed the presence of nitrergic and cholinergic neurons in investigated areas of the SC and indicated their fully functioning of NADPH-d and AChE positive structures in SC from the third postnatal week.

Dopamine-depletion and increased α-synuclein load induce degeneration of cortical cholinergic fibers in mice

Cognitive dysfunction can be common among Parkinson's disease (PD) patients, and multiplication of the gene α-synuclein (αsyn) increases the risk of dementia. Here, we studied the role of dopamine-depletion and increased αsyn load and aggregation on cholinergic structures in vivo. Wild-type (WT) and mice with A30P αsyn overexpression were treated subacutely with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and the number of cholinergic cells in their nucleus basalis magnocellularis-substantia innominata (NBM-SI), their cortical fiber density and their expression of different genes 1day or 90days after the last MPTP-injection were measured. Long-term dopamine depletion decreased the expression of choline acetyl transferase (ChAT) in the NBM-SI of WT mice, but no neuron loss was observed. In contrast, cortical cholinergic fiber density was decreased three months after MPTP-injection. Increased brain-derived neurotrophic factor expression could maintain cholinergic functions under these conditions. Expression of A30P αsyn in six-months-old transgenic mice resulted in decreased tyrosine receptor kinase B expression, and lower cortical cholinergic fiber density. Dopamine-depletion by MPTP induced cholinergic cell loss in the NBM-SI and increased cortical fiber loss. Our findings may explain why cholinergic cells are more vulnerable in PD, leading to an increased probability of dementia.

The role of mesopontine NGF in sleep and wakefulness

The microinjection of nerve growth factor (NGF) into the cat pontine tegmentum rapidly induces rapid eye movement (REM) sleep. To determine if NGF is involved in naturally-occurring REM sleep, we examined whether it is present in mesopontine cholinergic structures that promote the initiation of REM sleep, and whether the blockade of NGF production in these structures suppresses REM sleep. We found that cholinergic neurons in the cat dorso-lateral mesopontine tegmentum exhibited NGF-like immunoreactivity. In addition, the microinjection of an oligodeoxyribonucleotide (OD) directed against cat NGF mRNA into this region resulted in a reduction in the time spent in REM sleep in conjunction with an increase in the time spent in wakefulness. Sleep and wakefulness returned to baseline conditions 2 to 5days after antisense OD administration. The preceding antisense OD-induced effects occurred in conjunction with the suppression of NGF-like immunoreactivity within the site of antisense OD injection. These data support the hypothesis that NGF is involved in the modulation of naturally-occurring sleep and wakefulness.

The effects of acetates of aliphatic alcohols on the cholinergic nerve structures and the acetylcholine receptor of the guinea-pig ileum.

Abstract Isoamyl acetate, n-butyl acetate, n-amyl acetate and n-propyl acetate produced contractions of the isolated ileum of the guinea-pig. These were inhibited by atropine, procaine and by cooling. These acetates and also s-butyl, t-butyl and n-octyl acetate behaved as inhibitors of acetylcholine at 14 ± 1°. The acetylcholine content in the organ bath fluid increased after 60 min incubation of the ileum with isoamyl acetate. The results indicated that the agonistic acetates produced contraction of ileum through the liberation of acetylcholine from the cholinergic nerve-endings. All the acetates behaved as inhibitors of acetylcholine when they combined with the acetylcholine receptor on the muscle.

Lesion and stimulation of the ventral tegmental area increases cholinergic activity in the rat brain.

Our previous study indicated that unilateral lesion of the ventral tegmental area (VTA) facilitates contralateral VTA stimulation-induced feeding or exploration. The present study was aimed to determine the possible role of the central cholinergic systems in this effect. Immunohistochemistry for choline acetyltransferase (ChAT) was used to measure the number of active cholinergic neurons in their major groups (Ch1-Ch6) and in striatal regions in rats subjected to unilateral electrocoagulation and contralateral VTA electrical stimulation (L/S group) in comparison to the unilaterally stimulated (S), unilaterally lesioned (L) and sham (Sh) groups. The study showed that unilateral VTA lesion increased (as compared to Sh group) the number of ChAT+ neurons in the Ch1-Ch3 and unilateral VTA stimulation increased the number in the Ch1 and the ventral pallidum only. The most sensitive to these changes in the mesolimbic system were cholinergic structures providing hippocampal afferentation. Surprisingly, there was no significant increase in the number of ChAT+ neurons in the L/S group. The obtained results did not confirm any evident influence of the cholinergic systems on the VTA lesion-induced facilitation of the behavioral response evoked by contralateral VTA stimulation.

The α and β estrogen receptors in the human hypothalamus and basal forebrain in Alzheimer’s disease

Estrogen therapy in early menopause decreases the risk of Alzheimer’s disease. In contrast to the epidemiological and experimental evidence, no positive effects of estrogens on cognition were noted when estrogen therapy was prescribed to Alzheimer’s disease patients. We hypothesize that changes in canonical and alternatively spliced estrogen receptors (ERs) may play a role in these controversial findings. We found that nuclear expression of the ER α increases in the cholinergic structures of the basal forebrain and hypothalamic nuclei involved in cognitive functions and decreases in the hippocampus. Furthermore, certain brain areas in people over 50 years old had ER α splice variants with defective ligandand DNA-binding domains compromised AF1 activation function. The presence of different sets of classical and mutant estrogen receptors in different brain regions may account for the controversial effects of estrogens on cognitive functions in the climacteric period.

HISTOLOGICAL AND IMMUNOHISTOCHEMICAL STUDIES OF THE CORNEA OF SOME ANIMAL SPECIES; I. REAPPRAISAL OF CHOLINERGIC INNERVATION

The corneas of rat, mouse and guinea pig were investigated usinglight and electron microscopy as well as immunohistochemistry. We,here, examined the cholinergic structures in the cornea by immunohistochemistryfor choline acetyltransferase of the two forms, the alternativesplice variant from choline acetyltransferase (ChAT) cDNA preferentiallylocated in peripheral nerves (pChAT) and the common type (cChAT).Positive staining for cChAT was found only in non-neuronal epithelialcells, while pChAT positive staining occurred exclusively in nervefibers being distributed throughout the cornea. Such pChAT positivenerve axons were frequently smooth with few varicosities, except fortheir terminal swellings. The distribution pattern of pChAT positivenerves was compared with that of three neuropeptides known to befound in corneal nerves, including protein gene product 9.5 (PGP 9.5), substance P (SP) and calcitonin gene-related peptide (CGRP).The co-localization of pChAT with either of these neuropeptides hasbeen assumed on the base of their great similarity in distributionpattern and closeness in their routes inside the cornea. From theseresults it is concluded that rat, mouse and guinea pig corneas havelittle morphological differences and have a remarkable non-neuronalcholinergic activity in their epithelium together with what can besuggested to be cholinergic nerves represented in the pChAT positivenerve fibers. The function of acetyl choline in the corneal epitheliumand the possible origin and function of corneal cholinergic nerves hasbeen discussed.