Densitometric evaluation of markers for cholinergic transmission in rat superior olivary complex (original) (raw)
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The Journal of Comparative Neurology, 2003
Although the rabbit brain, in particular the basal forebrain cholinergic system, has become a common model for neuropathological changes associated with Alzheimer's disease, detailed neuroanatomical studies on the morphological organization of basal forebrain cholinergic nuclei and on their output pathways are still awaited. Therefore, we performed quantitative choline acetyltransferase (ChAT) immunocytochemistry to localize major cholinergic nuclei and to determine the number of respective cholinergic neurons in the rabbit forebrain. The density of ChAT-immunoreactive terminals in layer V of distinct neocortical territories and in hippocampal subfields was also measured. Another cholinergic marker, the low-affinity neurotrophin receptor (p75 NTR), was also employed to identify subsets of cholinergic neurons. Double-immunofluorescence labeling of ChAT and p75 NTR , calbindin D-28k (CB), parvalbumin, calretinin, neuronal nitric oxide synthase (nNOS), tyrosine hydroxylase, or substance P was used to elucidate the neuroanatomical borders of cholinergic nuclei and to analyze the neurochemical complexity of cholinergic cell populations. Cholinergic projection neurons with heterogeneous densities were found in the medial septum, vertical and horizontal diagonal bands of Broca, ventral pallidum, and magnocellular nucleus basalis (MBN)/substantia innominata (SI) complex; cholinergic interneurons were observed in the caudate nucleus, putamen, accumbens nucleus, and olfactory tubercule, whereas the globus pallidus was devoid of cholinergic nerve cells. Cholinergic interneurons were frequently
The localization of central cholinergic neurons
Progress in neuro-psychopharmacology & biological psychiatry, 1986
Over the past decade our understanding of the localization of central cholinergic neurons has greatly increased. Interest in these systems has also intensified due to the involvement of cholinergic mechanisms in Alzheimer's disease. The distribution of central cholinergic neurons is reviewed, focusing on recent work in experimental animals. The pharmacohistochemical procedure for acetylcholinesterase and the development of antibodies to choline acetyltransferase are two of the major technical advances that have shaped our knowledge of the distribution of central cholinergic neurons. The results, advantages and limitations of both techniques are discussed. A discussion of the phenomenon of coexistence of acetylcholine with neuroactive peptides in central neurons is also included.
Multiple origins of cholinergic innervation of the cochlear nucleus
Neuroscience, 2011
Acetylcholine affects a variety of cell types in the cochlear nucleus (CN) and is likely to play a role in numerous functions. Previous work in rats suggested that the acetylcholine arises from cells in the superior olivary complex, including cells that have axonal branches that innervate both the CN and the cochlea (i.e., olivocochlear cells) as well as cells that innervate only the CN. We combined retrograde tracing with immunohistochemistry for choline acetyltransferase to identify the source of ACh in the CN of guinea pigs. The results confirm a projection from cholinergic cells in the superior olivary complex to the CN. In addition, we identified a substantial number of cholinergic cells in the pedunculopontine tegmental nucleus (PPT) and the laterodorsal tegmental nucleus (LDT) that project to the CN. On average, the PPT and LDT together contained about 26% of the cholinergic cells that project to CN, whereas the superior olivary complex contained about 74%. A small number of additional cholinergic cells were located in other areas, including the parabrachial nuclei.
Neuroscience, 1987
The distribution of choline-acetyltransferase-like immunoreactive structures in the rat hypothalamus and preoptic area was examined by using avidin-biotin immunocytochemistry. We found that the hypothalamus is richly innervated by the cholinergic neuron system. Sites containing cholinergic neurons of varying density were: medial and lateral preoptic areas, septohypothalamic nucleus, median preoptic area, lateral hypothalamus including the perifornical area, anterior hypothalamic nucleus, arcuate nucleus, dorsomedial hypothalamic nucleus, posterior hypothalamic nucleus, dorsal and ventral premammilary nuclei, neuropil mediodorsal to the anterior hypothalamic nucleus, neuropil ventral to the anterior hypothalamic nucleus and ventromedial hypothalamic nucleus, neuropil between lateral hypothalamus and ventromedial hypothalamus, and neuropil between dorsal premammilary nucleus and posterior hypothalamic
Neuroscience, 1989
The distribution of cholinergic fibers in rat cortex was investigated using choline acetyltransferase immunohistochemistry. Previous studies have either shown differences in distribution, but have been limited to selected areas, or have shown no discernable differences between different cortical areas. In our study, we examined all areas of rat cortex and found that there are striking interareal and interlaminar differences in cholinergic fiber distribution. We have found that certain functionally similar cortical areas (e.g. sensory, motor, etc.) have similar patterns of cholinergic innervation and we have designated 13 general patterns of cortical cholinergic innervation. We have also compared, on an area-by-area basis, the pattern of acetylcholinesterase reactivity to that of choline acetyltransferase immunoreactivity, since acetylcholinesterase has been used for many years as a putative cholinergic marker. We found that in most cortical areas, the distribution of acetylcholinesterase-positive fibers paralleled that of choline acetyltransferase-immunoreactive fibers; however, there were some striking differences, notably primary somatosensory (the "barrelfield"), retrosplenial and cingulate cortices. In some areas, a revised concept of rat cortical organization, using cytoarchitectonics, was required.
Immunohistochemistry of cholinergic receptors
Anatomy and Embryology, 1992
Acetylcholine and its receptors are involved in a variety of important signal transduction processes. As shown here paradigmatically for the human neuromuscular junction and the cerebral cortex, acetylcholine receptors can be visualized immunohistochemically at the cellular and subcellular level under physiological and pathological conditions. At normal motor endplates nicotinic cholinoceptors are localized at the surface of the postsynaptic junctional folds. In myasthenic syndromes investigation of muscle biopsies enables the diagnosis of receptor deficiencies at the ultrastructural level. In normal cerebral cortex pyramidal neurons are equipped with both nicotinic and muscarinic acetylcholine receptors localized to postsynaptic densities. In neuropsychiatric diseases cholinoceptor expression can be monitored at the cellular level by quantititative assessment of immunolabeled cortical neurons.
Cholinergic innervation displays strikingly different laminar preferences in several cortical areas
Neuroscience Letters, 1986
A new rabbit polyclonal antiserum against choline acetyltransferase (CHAT) reveals that cholinergic innervation of the cortex varies strikingly among different cytoarchitecturally defined areas in the rat neocortex. These findings suggest that cholinergic transmission may be integrated differently into the local circuitries of various regions of the cerebral cortex. In addition, the pattern of staining observed with acetylcholinesterase histochemistry, which has been used for many years to demonstrate putative cholinergic fibers, only partially matches the staining pattern obtained with the more specific cholinergic marker. (?hAT.
Brain Research, 1994
This study describes the cellular distribution of muscarinic acetylcholine receptors (mAChRs) in the medial septum (MS), employing the monoclonal antibody M35 raised against purified mAChR-protein, mAChR-positive neurons are found throughout the MS, but are predominantly located in the midline area and in the lateral compartments. The labeled cell bodies are variable in shape and size (largest diameter ranging from 10-30 Izm), while both soma and the associated dendritic processes are densely stained for mAChRs. Astrocytes immunoreactive for mAChRs were frequently found associated with the large blood vessels in the midline area. To study the neurotransmitter nature of the mAChR-positive cells, immunofluorescence doublelabeling experiments were performed for mAChRs and GABAergic and cholinergic markers. GABAergic cells were identified immunocytochemically using antisera against glutamic acid decarboxylase (GAD), parvalbumin (PARV) or calbindin protein (CaBP). The cholinergic transmitter nature of the mAChR-positive cells was studied using adjacent 8 /xm thick serial sections stained immunocytochemically for choline acetyltransferase (CHAT), or histochemically for acetylcholinesterase (ACHE). These experiments showed that approximately half (52.3%) of all mAChR-positive cells contain GAD, whereas the other half is cholinergic. Conversely, nearly all GABAergic (98.6%) and cholinergic (96.9%) cells are endowed with mAChRs. GAD-positive terminals were found surrounding mAChR-positive perikarya which were either GAD-positive or GAD-negative, indicating GABAergic innervation on both GABAergic and cholinergic MS neurons. In general, the staining intensity for mAChRs appeared to be considerably higher in GABAergic than in cholinergic neurons, suggesting a stronger cholinergic impact upon the GABAergic neurons. The current anatomical findings contribute to the concept that the MS neurons form a firmly interconnected cell group, in which cholinergic neurotransmission mediated through mAChRs seems to play a significant role.
Neuroscience, 1998
Antibodies directed against the C-terminus of the rat vesicular acetylcholine transporter mark expression of this specifically cholinergic protein in perinuclear regions of the soma and on secretory vesicles concentrated within cholinergic nerve terminals. In the central nervous system, the vesicular acetylcholine transporter terminal fields of the major putative cholinergic pathways in cortex, hippocampus, thalamus, amygdala, olfactory cortex and interpeduncular nucleus were examined and characterized. The existence of an intrinsic cholinergic innervation of cerebral cortex was confirmed by both in situ hybridization histochemistry and immunohistochemistry for the rat vesicular acetylcholine transporter and choline acetyltransferase. Cholinergic interneurons of the olfactory tubercle and Islands of Calleja, and the major intrinsic cholinergic innervation of striatum were fully characterized at the light microscopic level with vesicular acetylcholine transporter immunohistochemistry. Cholinergic staining was much more extensive for the vesicular acetylcholine transporter than for choline acetyltransferase in all these regions, due to visualization of cholinergic nerve terminals not easily seen with immunohistochemistry for choline acetyltransferase in paraffin-embedded sections. Cholinergic innervation of the median eminence of the hypothalamus, previously observed with vesicular acetylcholine transporter immunohistochemistry, was confirmed by the presence of vesicular acetylcholine transporter immunoreactivity in extracts of median eminence by western blotting. Cholinergic projections to cerebellum, pineal gland, and to the substantia nigra were documented by vesicular acetylcholine transporter-positive punctate staining in these structures. Additional novel localizations of putative cholinergic terminals to the subependymal zone surrounding the lateral ventricles, and putative cholinergic cell bodies in the sensory mesencephalic trigeminal nucleus, a primary sensory afferent ganglion located in the brainstem, are documented here. The cholinergic phenotype of neurons of the sensory mesencephalic trigeminal nucleus was confirmed by choline acetyltransferase immunohistochemistry. A feature of cholinergic neurons of the central nervous system revealed clearly with vesicular acetylcholine transporter immunohistochemistry in paraffin-embedded sections is the termination of cholinergic neurons on cholinergic cell bodies. These are most prominent on motor neurons of the spinal cord, less prominent but present in some brainstem motor nuclei, and apparently absent from projection neurons of the telencephalon and brainstem, as well as from the preganglionic vesicular acetylcholine transporter-positive sympathetic and parasympathetic neurons visualized in the intermediolateral and intermediomedial columns of the spinal cord. In addition to the large puncta decorating motor neuronal perikarya and dendrites in the ventral horn, vesicular acetylcholine transporter-positive terminal fields are distributed in lamina X surrounding the central canal, where additional small vesicular acetylcholine transporter-positive cell bodies are located, and in the superficial layers of the dorsal horn. Components of the central cholinergic nervous system whose existence has been controversial have been confirmed, and the existence of new components documented, with immunohistochemistry for the vesicular acetylcholine transporter. Quantitative visualization of terminal fields of known cholinergic systems by staining for vesicular acetylcholine transporter will expand the possibilities for documenting changes in synaptic patency accompanying physiological and pathophysiological changes in these systems. 1998 IBRO. Published by Elsevier Science Ltd.
The Journal of Comparative Neurology, 1993
We investigated (1) the topography of projection neurons in the nucleus basalis of Meynert (NBM) with efferents to restricted regions of the primary somatosensory (SI), the second somatosensory (SII), and the primary motor (MI) cortices in the rat; (2) the percentage of these NBM projection neurons that were cholinergic; and (3) the collateralization, if any, of single NBM neurons to different subdivisions within SI, to homotopic areas of SI and SII, and to homotopic areas of SI and MI. Retrograde single-and double-labeling techniques were used to study NBM projections to electrophysiologically identified subdivisions of SI and to homotopic representational areas of SI and SII, and of SI and MI. Choline acetyltransferase immunocytochemistry was done to identify cholinergic NBM neurons. Of the retrogradely labeled NBM neurons that projected to selective subdivisions of SI, SII, and MI, 89%, 87%, and 88%, respectively, were cholinergic. We found a rostral-to-caudal progression of retrogradely labeled NBM neurons following a medial-to-lateral sequence of injections into subdivisions of S1. Overlapping groups of single-labeled NBM neurons were observed after injections of different tracers into adjacent subdivisions within SI or homotopic areas of SI and SII, and of SI and MI. We conclude that NBM innervation to SI, SII, and MI is mostly cholinergic in the rat, that each cortical area receives cholinergic afferents from neurons widely distributed within the NBM, and that each NBM neuron projects to a restricted cortical area without significant collateralization to adjacent subdivisions within SI or to homotopic areas of SI and SII, or SI and MI.