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1.
The topographic distribution of central cholinergic and catecholaminergic neurons has been investigated in the baboon (Papio papio). The perikarya were mapped on an atlas through the brain and spinal cord employing sections processed for acetylcholinesterase (AChE) pharmacohistochemistry coupled with choline acetyltransferase (ChAT) immunohistochemistry or aqueous catecholamine-fluorescence histochemistry. Compared with subprimates, there is a remarkable increase in the volume occupied by and the number of cholinergic cells contained in the nucleus basalis and nucleus tegmenti pedunculopontinus (subnucleus compacta). The elaboration of these parts of the cholinergic system is accompanied by a large extension of catecholaminergic cell groups in the midbrain (groups A8-A10), particularly the substantia nigra (pars compacta), and in the dorsolateral pontine tegmentum (A5-A7 complex). Although cholinergic and catecholaminergic soma generally occupy distinctly different regions of the brain, a close apposition of cholinergic and noradrenergic neurons occurs in the dorsolateral pontine tegmentum. In the peripeduncular region ChAT-positive cells and green fluorescent neurons of the A6-A7 complex form parallel lines and do not intermingle as has previously been demonstrated in the cat. Two distribution patterns, aggregated or disseminated, are another common feature of central cholinergic and catecholaminergic perikarya. The cholinergic neurons in the nucleus tegmenti pedunculopontinus and the catecholaminergic neurons in A6-A7 complex display both patterns. This comparative study of three transmitter systems in the baboon suggests that the cholinergic as well as the catecholaminergic neurons that give rise to ascending telencephalic and dorsal diencephalic projections undergo phylogenetic development in terms of cell number and nuclear volume.  相似文献   

2.
Microinjection of cholinergic agonists in a dorsolateral part of the mesopontine tegmentum has been shown to induce a rapid eye movement (REM) sleep-like state. Physiological evidence indicates that not only acetylcholine but also various amine transmitters, including those implicated in behavioral state regulation, affect neuronal activity in this region of the pontine reticular formation. In the present study, sources of select aminergic and cholinergic inputs to this REM sleep induction zone were identified and quantitatively analyzed by using fluorescence retrograde tracing combined with immunofluorescence in the rat. In addition to previously demonstrated cholinergic projections from the pedunculopontine and laterodorsal tegmental nuclei, the REM sleep induction zone received various aminergic inputs that originated in widely distributed regions of the brainstem and hypothalamus. Serotoninergic afferents represented a mean of 44% of all aminergic/cholinergic source neurons projecting to the REM sleep induction zone, which was comparable to the mean percentage of 39% represented by cholinergic afferent neurons. The serotoninergic afferents originated from the raphe nuclei at all brainstem levels, with heavier projections from the pontine than from the medullary raphe nuclei. Unexpectedly, an additional major serotoninergic input was provided by serotoninergic neurons in the nucleus prosupralemniscus (B9). Noradrenergic afferent neurons represented a mean of 14% of all aminergic/cholinergic source neurons, which was only about one-third of the mean percentage of either cholinergic or serotoninergic source neurons. These noradrenergic projection neurons were located not only in the locus ceruleus (8%) but also in the lateral tegmentum, including the A5 (4%) and A7 (2%) cell groups. Histaminergic neurons in the tuberomammillary hypothalamic nucleus represented a minor group of afferent neurons (3%), and a still smaller input came from adrenegic C1 neurons. The pattern of these transmitter-specific afferent connections appeared to be similar regardless of the longitudinal level within the REM sleep induction zone. The present results are consistent with previous behavioral and physiological evidence for a role of the pontine REM sleep induction zone in triggering REM sleep. The regulation of REM sleep induction would be best understood in terms of a state-dependent interplay of cholinergic, serotoninergic, and other inputs all acting convergently upon neurons in the REM sleep-inducing region of the pontine reticular formation.  相似文献   

3.
为研究家兔脑桥排尿反射通路的构成,本实验采用顺、逆行追踪技术结合免疫组化方法对家兔脑桥被盖背外侧部与骶髓的纤维联系进行了研究。将麦芽凝集素辣根过氧化物酶(WGA-HRP)或荧光素四甲基罗达明葡聚糖胺(TMR)注射到骶髓后,在脑桥被盖背外侧部发现一团WGA-HRP或TMR标记的神经元。为确定这些逆标细胞是否属于蓝斑核内的神经元,将TMR注射例的脑桥切片用抗酪氨酸羟化酶(TH)抗体孵育并进行免疫荧光组化染色。结果显示,TH阳性细胞环绕于TMR标记神经元周围,但未见TMR/TH双标细胞。将WGA-HRP注射于脑桥被盖背外侧部后,在骶髓节段的骶髓副交感核、中间带灰质和后连合核等处发现有大量顺行标记的纤维和终末。结合在其他种属动物上的研究资料,推测位于家兔脑桥被盖背外侧部的这团神经元可能相当于在大鼠和猫相应部位发现的与脑桥排尿反射密切相关的Barrington核  相似文献   

4.
By use of retrograde transport of horseradish peroxidase-wheat germ agglutinin (HRP-WGA) in combination with monoclonal antibodies against choline acetyltransferase (ChAT), we show that putative cholinergic inputs to the feline pontine nuclei originate from cells in the dorsolateral pontine tegmentum. These cells form a loosely arranged continuum that nevertheless may be subdivided into two groups on the basis of differences in cell morphology. One group consists of double-labeled cells in the periventricular gray substance medial to, and partly merging with, the nucleus locus coeruleus. The other group consists of double-labeled cells surrounding the brachium conjunctivum. In two cats with tracer injections in the pontine nuclei, 81% and 84%, respectively, of the retrogradely labeled cells in the dorsolateral pontine tegmentum are ChAT-like immunoreactive (ChAT-LI). In the same experiments, many ChAT-LI cells, but no retrogradely labeled cells, are seen in the basal telencephalon. The pontine nuclei contain a plexus of thin ChAT-LI fibers with varicosities resembling en passant as well as terminal boutons. These ChAT-LI fibers appear to branch extensively and cover all parts of the pontine nuclei. Following injections of rhodamine-B-isothiocyanate (RITC) in the thalamus and Fluoro-Gold in the pontine nuclei and surrounding regions in the same animal, all retrogradely labeled cells in the dorsolateral pontine tegmentum are labeled with both tracers, whereas most cells in the paramedian pontine reticular formation are labeled either with RITC or Fluoro-Gold. Thus it appears that all cells in the dorsolateral pontine tegmentum that project to the pontine nuclei also project to the thalamus. In analogy with findings by others in the dorsal lateral geniculate nucleus, we suggest that the putative cholinergic projections to the pontine nuclei may serve to modulate transmission of cerebellar afferent information in accordance with the behavioral state of the animal.  相似文献   

5.
The distribution of catecholaminergic and cholinergic neurons in the upper brainstem of the ferret were mapped by staining immunohistochemically two adjacent series of sections of brainstem for tyrosine hydroxylase and choline acetyltransferase, respectively. As in other species, large numbers of tyrosine-hydroxylase-positive neurons are localized in the ventral tegmental area (A10), the substantia nigra (A9), and in A8. Tyrosine-hydroxylase-positive neurons in the dorsolateral pontine tegmentum (A4, A6, and A7--the locus coeruleus complex) of the ferret are rather diffusely distributed, as has been observed in other carnivore species such as the cat and the dog, but unlike the cat, these cells in the ferret display a relative uniformity in size and morphology. Choline-acetyltransferase-positive neurons which extend in the ferret's pedunculopontine tegmental nucleus and ventral parabrachial area (Ch5) are relatively large cells that stain intensely for choline acetyltransferase, and their dendrites form prominent bundles in regions where unstained fibre tracts are prevalent. Choline-acetyltransferase-positive neurons distributed in the laterodorsal tegmental nucleus (Ch6) are smaller than the cholinergic cells of Ch5, and they stain less intensely for choline acetyltransferase. Rostrally, there is little overlap between the catecholaminergic cell groups A8, A9, and A10 and the cholinergic cell groups of Ch5 and Ch6. Caudally, the Ch5 neurons extend some considerable extent into the locus coeruleus complex. In the region of overlap, no cells with staining for both tyrosine hydroxylase and choline acetyltransferase were observed, as was ascertained with a double staining method employing a combination of tyrosine hydroxylase immunofluorescence and choline acetyltransferase peroxidase-antiperoxidase immunohistochemistry. In conclusion, the ferret has a typically carnivore pattern for the distribution of catecholaminergic cells in the upper brainstem, and there is a significant overlap between the catecholaminergic and cholinergic cell groups in the dorsolateral pontine tegmentum.  相似文献   

6.
The dorsolateral pontine tegmentum of the cat is known to contain enkephalinergic neurons, with most of the enkephalin co-contained in the catecholaminergic neurons; however, enkephalinergic cells projecting to the spinal cord have not been identified. This study employs retrograde transport of horseradish peroxidase in combination with methionine-enkephalin or tyrosine hydroxylase immunocytochemistry to 1) determine the locations of pontospinal enkephalinergic neurons and 2) compare these with the locations of pontospinal catecholaminergic neurons. Pontospinal enkephalinergic neurons were observed in the nuclei locus coeruleus and subcoeruleus and the K?lliker-Fuse nucleus. A high concentration of these neurons was evident in the K?lliker-Fuse nucleus when compared to the nuclei locus coeruleus and subcoeruleus (P less than .01). Both the enkephalinergic and catecholaminergic neurons projecting to the spinal cord were located in the same general areas of the dorsolateral pontine tegmentum and there was no significant difference in the mean diameters of these two neuronal types (P greater than .05). Quantitative data concerning the pontospinal enkephalinergic neurons correlated well with previous data on pontospinal catecholaminergic neurons (Reddy et al., Brain Res. 491:144-149, '89). A majority of the descending neurons from the dorsolateral pontine tegmentum contain enkephalin (72-80%) and catecholamine (80-87%). The observations suggest that enkephalin is contained in many of the pontospinal catecholaminergic neurons.  相似文献   

7.
The distribution and morphological characteristics of monoamine (MA)-containing neuronal somata in the brain stem of kittens and of adult cats were studied by means of the Falck-Hillarp histofluorescence method. This investigation has shown, among other things, that in the midbrain of the cat the catecholamine (CA) perikarya are chiefly confined to the pars compacta of the substantia nigra, the ventromedial tegmental area, the nucleus linearis rostralis and the nucleus parabrachialis pigmentosus. Numerous CA neurons are also present in the dorsolateral part of the pontine tegmentum but also within the nucleus subcoeruleus, in nuclei lemnisci lateralis dorsalis and in nuclei parabrachialis lateralis and medialis. In the medulla, a few CA neuronal somata are lying near the hypoglossal nucleus whereas a larger number of CA cell bodies occur at the level of nucleus reticularis lateralis and in nucleus paragigantocellularis lateralis. On the other hand, most of the serotonin (5-HT) perikarya are confined to the raphe nuclei of the brain stem: nuclei raphe dorsalis, centralis superior, raphe pontis, raphe magnus, raphe pallidus and raphe obscurus. Some 5-HT neuronal somata are also found lateral to the pyramidal tract and to the inferior olivary complex. The various similarities and differences in respect to the pattern of the topographical distribution of MA neurons in the brain stem of the cat as compared to that of other mammals are discussed.  相似文献   

8.
The aim of the present study was to determine the brainstem afferents and the location of neurons giving rise to monoaminergic, cholinergic, and peptidergic inputs to the cat trigeminal motor nucleus (TMN). This was done in colchicine treated animals by using a very sensitive double immunostaining technique with unconjugated cholera-toxin B subunit (CT) as a retrograde tracer. After CT injections in the TMN, retrogradely labeled neurons were most frequently seen bilaterally in the nuclei reticularis parvicellularis and dorsalis of the medulla oblongata, the alaminar spinal trigeminal nucleus (magnocellular division), and the adjacent pontine juxtatrigeminal region and in the ipsilateral mesencephalic trigeminal nucleus. We further observed that inputs to the TMN arise from the medial medullary reticular formation (the nuclei retricularis magnocellularis and gigantocellularis), the principal bilateral sensory trigeminal nucleus, and the dorsolateral pontine tegmentum. In addition, the present study demonstrated that the TMN received 1) serotonergic afferents, mainly from the nuclei raphe obscurus, pallidus, and dorsalis; 2) catecholaminergic afferent projections originating exclusively in the dorsolateral pontine tegmentum, including the K?lliker-Fuse, parabrachialis lateralis, and locus subcoeruleus nuclei; further, that 3) methionin-enkephalin-like inputs were located principally in the medial medullary reticular formation (nuclei reticularis magnocellularis and gigantocellularis and nucleus paragigantocellularis lateralis), in the caudal raphe nuclei (Rpa and Rob) and the dorsolateral pontine tegmentum; 4) substance P-like immunoreactive neurons projecting to the TMN were present in the caudal raphe and Edinger-Westphal nuclei; and 5) cholinergic afferents originated in the whole extent of the nuclei reticularis parvicellularis and dorsalis including an area located ventral to the nucleus of the solitary tract at the level of the obex. In the light of these anatomical data, the present report discusses the possible physiological involvement of TMN inputs in the generation of the trigeminal jaw-closer muscular atonia occurring during the periods of paradoxical sleep in the cat.  相似文献   

9.
The neuroanatomical location and cytological features of cholinergic neurons in the rat brain were determined by the immunocytochemical localization of the biosynthetic enzyme, choline acetyltransferase (ChAT). Perikarya labeled with ChAT were detected in four major cell groups: (1) the striatum, (2) the magnocellular basal nucleus, (3) the pontine tegmentum, and (4) the cranial nerve motor nuclei. Labeled neurons in the striatum were observed scattered throughout the neostriatum (caudate, putamen) and associated areas (nucleus accumbens, olfactory tubercle). Larger ChAT-labeled neurons were seen in an extensive cell system which comprises the magnocellular basal nucleus. This more or less continuous set of neuronal clusters consists of labeled neurons in the nucleus of the diagonal band (horizontal and vertical limbs), the magnocellular preoptic nucleus, the substantia innominata, and the globus pallidus. Labeled neurons in the pontine tegmentum were seen as a group of large neurons in the caudal midbrain, dorsolateral to the most caudal part of the substantia nigra, and extended in a caudodorsal direction through the midbrain reticular formation into the area surrounding the superior cerebellar peduncle. The neurons in this latter group constitute the pedunculopontine tegmental nucleus (PPT). An additional cluster of cells was observed medially adjacent to the PPT, in the lateral part of the central gray matter at the rostral end of the fourth ventricle. This group corresponds to the laterodorsal tegmental nucleus. Large ChAT-labeled neurons were also observed in all somatic and visceral motor nerve nuclei. The correspondence of the distribution of ChAT-labeled neurons identified by our methods to earlier immunocytochemical and acetylcholinesterase histochemical studies and to connectional studies of these groups argues for the specificity of the ChAT antibody used.  相似文献   

10.
The topographical distribution of neurons containing acetylcholinesterase (AChE, EC 3.1.1.7) in the basal forebrain and upper brainstem of the squirrel monkey (Saimiri sciureus) was studied by means of Butcher's pharmacohistochemical technique which involves staining for AChE at various times after the systemic administration of the AChE inhibitor di-isopropylphosphorofluoridate (DFP). Only those neurons whose AChE staining was as intense as that of known cholinergic neurons present in the same material (e.g., neurons of cranial nerve nuclei) were examined and mapped. Three major collections of such strongly-stained AChE neurons were disclosed in squirrel monkey brain: one located in the striatum, the other lying along the ventralmost aspects of the basal forebrain, and a third one present within the midbrain-pontine tegmentum. The striatal AChE neurons vary in shape from fusiform with 2 thick processes to polygonal with 4-5 thinner processes. They are uniformly scattered throughout the caudate nucleus and putamen and represent only a small proportion of the total striatal cell population (4-6 cells/mm2). They most likely correspond to the aspiny type II cells described in Golgi material of monkey striatum. Similar neurons occur also in ventral striatal areas comprising nucleus accumbens septi and the deep polymorph layer of the olfactory tubercle. The second major AChE neuronal population is composed of the magnocellular neurons that form a somewhat continuous chain of neuronal aggregates extending rostrocaudally from the septal region to the caudal pole of the lentiform nucleus. It includes the neurons of the medial septal nucleus, the nucleus of the diagonal band of Broca and the nucleus basalis of Meynert, all displaying strikingly similar morphological and histochemical characteristics. The AChE neuronal population of nucleus basalis encroaches markedly upon the lateral hypothalamus laterally and the globus pallidus dorsally. The third important AChE cell collection occurs within the pedunculopontine nucleus area in upper brainstem. In that constellation, the AChE neurons are clustered in 2 continuous cell groups: one located dorsolaterally, the other lying ventromedially to the brachium conjunctivum. The thick processes of these neurons form impressive AChE neuronal networks that surround and pervade the brachium conjunctivum over long distances. This cell group, which is one of the most highly AChE reactive structures of the entire brain in the squirrel monkey, may provide a major cholinergic input to various basal ganglia structures, particularly the substantia nigra.  相似文献   

11.
A group of medium-to-large cholinergic neurons situated in the dorsolateral mesopontine tegmentum comprises the pedunculopontine tegmental nucleus (PPT). The PPT pars compacta (PPT-pc), which occupies the lateral part of the caudal two-thirds of the nucleus, contains a dense aggregation of cholinergic neurons. In the present study, we have employed immunohistochemistry for choline acetyltransferase (ChAT) and electron microscopy to investigate the ultrastructure and synaptic organization of neuronal elements in the PPT-pc. Our results demonstrate that: (1) ChAT-immunoreactive (i.e., cholinergic) PPT-pc neurons are characterized by abundant cytoplasm and organelles, and have few axosomatic synapses (both asymmetric and symmetric); (2) ChAT-immunoreactive dendrites comprise 6-15% of total dendritic elements in the neuropil; the mean percentage of dendritic membrane covered by synaptic terminals is approximately 15%, and nearly all synapses with ChAT-immunoreactive dendrites are asymmetric; (3) within the boundaries described by cholinergic PPT-pc, there are noncholinergic neurons which, in contrast, exhibit a lucent cytoplasm and a higher frequency of axosomatic synapses (10.5% versus 3.7% for cholinergic neurons); and (4) noncholinergic neurons are morphologically heterogeneous with one subpopulation exhibiting a mean diameter that approximates that of cholinergic cells (i.e., >15 μm and <20 μm) and a very high frequency of axosomatic synapses (>20%). Only 0.2-0.7% of terminal elements in the neuropil were ChAT-immunoreactive and these were not observed to synapse with cholinergic dendrites or somata. This relative paucity of terminal labeling and lack of cholinergic-cholinergic interactions seems inconsistent with the recognized and prominent physiological actions of acetylcholine on cholinergic PPT-pc neurons, and suggests a methodological limitation and/or a potential paracrine-like action of nonsynaptically released acetylcholine in the PPT region. J. Comp. Neurol. 382:285-301, 1997. © 1997 Wiley-Liss, Inc.  相似文献   

12.
The motoneurons innervating the orbicularis oculi muscle from a subgroup within the facial nucleus, called the intermediate facial subnucleus. This makes it possible to study afferents to these motoneurons by means of autoradiographical tracing techniques. Many different injections were made in the brainstem and diencephalon and the afferent projections to the intermediate facial subnucleus were studied. The results indicated that these afferents were derived from the following brainstem areas: the dorsal red nucleus and the mesencephalic tegmentum dorsal to it; the olivary pretectal nucleus and/or the nucleus of the optic tract; the dorsolateral pontine tegmentum (parabrachial nuclei and nucleus of K?lliker-Fuse) and principal trigeminal nucleus; the ventrolateral pontine tegmentum at the level of the motor trigeminal nucleus; the caudal medullary medial tegmentum; the lateral tegmentum at the level of the rostral pole of the hypoglossal nucleus and the ventral part of the trigeminal nucleus and the nucleus raphe pallidus and caudal raphe magnus including the adjoining medullary tegmentum. These latter projections probably belong to a general motoneuronal control system. The mesencephalic projections are mainly contralateral, the caudal pontine and upper medullary lateral tegmental projections are mainly ipsilateral and the caudal medullary projections are bilateral. It is suggested that the different afferent pathways subserve different functions of the orbicularis oculi motoneurons. Interneurons in the dorsolateral pontine and lateral medullary tegmentum may serve as relay for cortical and limbic influences on the orbicularis oculi musculature, while interneurons in the ventrolateral pontine and caudal medullary tegmentum may take part in the neuronal organization of the blink reflex.  相似文献   

13.
In the current study, the distribution of noradrenergic neurons in the pontine tegmentum that project to the cochlear nucleus was determined with retrograde tract tracing combined with neurotransmitter immunohistochemistry in the cat. Double-labeled neurons were observed in all noradrenergic cell groups, in both the dorsolateral and the ventrolateral tegmentum. Half of the double-labeled cells were located in the locus coeruleus complex. Most of these were situated in its ventral division. Most other double-labeled cells were located in peribrachial regions, especially lateral to the brachium conjunctivum. Relatively few double-labeled cells were observed in both the A4 and the A5 cell groups, 2% and 0.4%, respectively, of the total. Except for neurons in A5, which projected only contralaterally, the projections were bilateral, with an ipsilateral preponderance. The results indicate that neurons located in the ipsilateral dorsolateral tegmentum, namely, in the locus coeruleus complex and the peribrachial region, are the primary source of pontine noradrenergic afferents to the cochlear nucleus of the cat.  相似文献   

14.
It is now accepted that sleep is induced by biological clock located in the suprachiasmatic nucleus and/or sleep promoting substances, which influence ventrolateral preoptic (VLPO) neurons. The VLPO neurons affects more caudally situated posterior hypothalamic ones containing orexine and/or histamine, reciprocally. When these neurons inhibit lower brainstem aminergic ones, sleep is induced. REM (Rapid Eye Movement) sleep can be induced mainly by brainstem cholinergic neurons, when aminergic ones are completely inhibited. During this stage, tonic activities and phasic Ponto-Geniculate-Occipital (PGO) ones originated within brainstem cholinergic neurons activate irregularly many parts of the brain such as the cerebral cortex and limbic system to produce dream-like activity. Muscle atonia is also observed during REM sleep. This atonia is caused by neurons in the pontine reticular inhibitory area (PIA), which is normally inhibited by aminergic inputs. The PIA affects medullary neurons of the paramedian and/or magnocelullar nuclei to regulate motoneurons in the ventral horn. Therefore. muscle atonia is produced when these PPT cells are active during REM sleep. In addition, based upon many recent data, sleep is not a passive state but rather an active state, during which recuperation of neuronal system is promoted and information processing is executed.  相似文献   

15.
The effect of concussive head injury on central cholinergic neurons   总被引:1,自引:0,他引:1  
This study examined the effect of fluid percussion head injury on the activity of cholinergic neurons in specific brain areas of the rat 12 min, 4 h and 24 h following injury. Acetylcholine (ACh) turnover, used as an index of cholinergic neuronal activity, was determined using a gas chromatographic-mass spectrometric technique. The most striking changes in cholinergic activity were observed in the dorsal pontine tegmentum, where concussive head injury produced an increase in ACh turnover 12 min and 4 h following injury. This area has been previously associated with behavioral changes observed following concussive injury. ACh turnover in the thalamus, a region to which pontine cholinergic neurons project, also tended to increase 4 h following injury. On the other hand, ACh turnover tended to decrease in the amygdala 4 h following injury. Although there were no significant changes in hippocampal ACh content or turnover following injury. ACh content did tend to increase in that brain region 12 min following injury. There were no significant effects of injury on cholinergic neurons in the cingulate/frontal cortex. These changes in cholinergic neuronal activity may contribute to the neurological deficits following concussive injury. In particular, activation of cholinergic neurons in the pontine region may contribute to components of behavioral suppression associated with reversible traumatic unconsciousness. More generalized changes in cholinergic function may lead to the production of more chronic deficits.  相似文献   

16.
Choline acetyltransferase (ChAT) immunocytochemistry and lectin-conjugated horseradish peroxidase (WGA-HRP) histochemistry were combined at the electron microscopic level to examine the morphology of cholinergic terminals in the canine centrum medianum-parafascicular complex (CM-Pf) and to localize cholinergic terminals making synaptic contact with retrogradely labeled CM-Pf thalamostriatal projection neurons. Following WGA-HRP injections into the caudate nucleus, CM-Pf neurons were heavily labeled with WGA-HRP reaction product. Examination with the electron microscope revealed retrogradely labeled neurons characterized by a large nucleus with deep infoldings of the nuclear envelope. ChAT-positive terminals were observed arising from small-diameter nonmyelinated axonal profiles. These terminals varied in size from 0.5 to 1.4 micron in long diameter. The smaller terminals (0.5-0.7 micron) were seen most frequently and established symmetrical or slightly asymmetrical synaptic contacts with small dendritic profiles. The larger ChAT-positive terminals (1.0-1.4 micron) were less frequently observed, contained several mitochondria and small clusters of pleomorphic vesicles, and contacted large dendritic shafts and cell somata. Some of the postsynaptic targets of both smaller and larger ChAT-positive terminals were identified as belonging to retrogradely HRP-labeled thalamostriatal neurons. These observations indicate that at least some thalamostriatal neurons within the CM-Pf complex are innervated by cholinergic terminals which probably arise from ChAT-positive cell bodies located within the pontomesencephalic tegmentum, particularly within the nucleus tegmenti pedunculopontinus and the laterodorsal tegmental nucleus. These findings provide evidence for direct influence by cholinergic brainstem nuclei over activities of thalamostriatal neurons.  相似文献   

17.
The question of which brainstem neuronal receptors can mediate cholinergic REM sleep induction was investigated by injecting the pure muscarinic agonist bethanechol via glass micropipettes in the pontine tegmentum of cats. The REM sleep enhancement was observed to be equally potent, equally dose-dependent and its appearance equally site-dependent as that previously observed with carbachol, a mixed muscarinic/nicotinic agonist. The results suggest that the pharmacological activation of muscarinic receptors in pontine neurons is sufficient to trigger REM sleep.  相似文献   

18.
Nitric oxide (NO) is a biological messenger synthesized by three main isoforms of NO synthase (NOS): neuronal (nNOS, constitutive calcium dependent), endothelial (eNOS, constitutive, calcium dependent) and inducible (iNOS, calcium independent). NOS is distributed in the brain either in circumscribed neuronal sets or in sparse interneurons. Within the laterodorsal tegmentum (LDT), pedunculopontine tegmentum and dorsal raphe nucleus, NOS-containing neurons overlap neurons grouped according to their contribution to sleep mechanisms. The main target for NO is the soluble guanylate cyclase that triggers an overproduction of cyclic guanosine monophosphate. NO in neurons of the pontine tegmentum facilitates sleep (particularly rapid-eye-movement sleep), and NO contained within the LDT intervenes in modulating the discharge of the neurons through an auto-inhibitory process involving the co-synthesized neurotransmitters. Moreover, NO synthesized within cholinergic neurons of the basal forebrain, while under control of the LDT, may modulate the spectral components of the EEG instead of the amounts of different sleep states. Finally, impairment of NO production (e.g. neurodegeneration, iNOS induction) has identifiable effects, including ageing, neuropathologies and parasitaemia.  相似文献   

19.
The localization of Barrington's nucleus in the dorsolateral pons of the rabbit and its projections to the sacral spinal cord were examined by using retrograde and anterograde labeling methods combined with immunohistochemistry. After injection of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) or a fluorescence tracer, tetramethylrhodamine-dextran amine (TMR), into the sacral spinal cord segments, a cluster of neurons labeled with WGA-HRP or TMR were seen in the pontine dorsolateral tegmentum. To identify whether the retrogradely labeled neurons were situated within the locus coeruleus, the sections containing TMR-labeled neurons through the pons were incubated with anti-tyrosine hydroxylase (TH) antibody and observed under epifluorescence microscope. It was shown that the cluster of TMR-labeled neurons in the dorsolateral tegmentum were surrounded by TH-positive neurons, but they were negatively immunostained with TH-like immunoreactivity. In anterograde experiment, injection of WGA-HRP into the dorsolateral tegmentum resulted in many anterogradely labeled nerve fibers and terminals in the sacral spinal cord, including the sacral parasympathetic nucleus. The present results suggest that the cluster of neurons in the dorsolateral tegmentum of the rabbit may correspond to Barrington's nucleus revealed in the rat and cat, and thus may be involved in micturtion reflex of the rabbit.  相似文献   

20.
The substantia innominata encompasses an area of the basal forebrain that is ventral to the lenticular nucleus and anterior commissure, medial to the claustrum and external capsule, and lateral to the hypothalamus. The nucleus basalis of Meynert consists primarily of large acetylcholinesterase (AchE)-positive neurons embedded within the substantia innominata. Damage to these neurons may be important in the pathogenesis of cortical dysfunction in Alzheimer's disease. In order to characterize other neuronal elements in the substantia innominata and their relationship to the nucleus basalis, we chose to study a biochemically distinct neuronal subset containing the enzyme nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d). The substantia innominata was blocked from six normal brains obtained postmortem and fixed in neutral-buffered formalin at 4 degrees C for 48 hours. Free-floating 50-micron sections from several levels were stained for NADPH-d or AchE activities. Selected sections were double stained for NADPH-d and AchE. NADPH-d activity was present in a network of pleomorphic neurons that extended through all levels of the substantia innominata and into the striatum and amygdala. NADPH-d neurons were particularly numerous at the level of the anterior commisure and were closely associated with the cholinergic neurons of the nucleus basalis. They were not seen in the ventral pallidum, or the vertical limb of the diagonal band of Broca or in the islands of Calleja. The cell bodies of NADPH-d neurons were quite varied in shape, ranging from ovoid to fusiform, and about half the cells were bipolar. Where neuronal density was high, their dendrites formed an interlacing pattern. NADPH-d-positive fibres were seen coursing through the external capsule, hypothalamus, and amygdala. This novel set of neurons in the substantia innominata may be part of a more extensive network that interacts with the magnocellular basal forebrain system at the level of the nucleus basalis. Whether other neurotransmitters are present within these neurons and whether NADPH-d neurons are involved in Alzheimer's disease remain to be elucidated.  相似文献   

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