摘要:

AbstractAcetylcholine (ACh) plays a major role in central autonomic regulation, including the control of arterial blood pressure (AP). Previously unknown neuroanatomic substrates of cholinergic ‐ autonomic control were mapped in this study. Cholinergic perikarya and bouton‐like varicosities were localized by an immunocytochemical method empolying a monoclonal antiserum against choline acetyltransferase (ChAT), the enzyme synthesizing ACh.In theforebrain, bouton‐like varicosities and/or perikarya were detected in the septum, bed nucleus of the stria terminalis, amygdala (in particular, autonomic projection areas AP1and AP2bordering the central subnucleus, hypothalamus rostrolateral/innominata transitional area, perifornical, dorsal, incertal, caudolateral, posterior [PHN], subparafascicular, supramammillary and mammillary nuclei. Few or no punctate varicosities were labeled in the paraventricular (PVN) or supraoptic (SON) hypothalamic nuclei.In themid and hindbrain, immunoreactive cells and processes were present in the nucleus of Edinger‐Westphal, periaqueductal gray, parabrachial complex (PBC), a periceruleal zone avoiding the locus ceruleus (LC), pontine micturition field, pontomedullary raphe, paramedian reticular formation and periventricular gray, A5 area, lateral tegmental field, nucleus tractus solitarii (NTS), nucleus commissuralis, nucleus reticularis rostroventrolateralis (RVL), and the ventral medullary surface (VMS).In the PBC, immunoreactive varicosities identified areas previously unexplored forcholinergicautonomic responsivity superior, internal, dorsal, and central division of the lateral subnucleus, nucleus of Koelliker‐Fuse and the medial subnucleus. In the NTS, previously undescribed ChAT‐immunolabeled cells and processes were concentrated at intermediate and subpostermal levels and distributed viscerotopically in areas receiving primary cardiopulmonary afferents. In the nucleus RVL, cholinergic perikarya were in proximity to the VMS and medial to adrenergic cell bodies of the C1 area. Punctate varicosities of unknown origin and dendrites extending ventrally from the nucleus ambiguus overlapped the C1 area and immediate surround of RVL.In conclusion: 1) Cholinergic perikarya and putative terminal fields, overlap structures that are rich in cholinoreceptors and express autonomic, neuroendocrine, or behavioral responsivity to central cholinergic stimulation (PHN, NTS, RVL). The role of ACh in most immunolabeled areas, however, has yet to be determined. Overall, these data support the concept that cholinergic agents act at multiple sites in the CNS and with topographic specificity. (2) The absence of immunoreactive elements in the LC, PVN, and SON was unexpected and suggests that cholinergic processing attributed to these nuclei is mediated polysynaptically or by synapses on processes extending into adjacent cholinoreceptor fields. (3) Putative cholinergic terminals overlapping sites that relay primary (NTS) or higher‐order visceral afferents suggest anatomical substrates for cholinergic regulation of autonomic reflexes. (4) ChAT‐immunoreactive terminals in areas where cells project to the IML support the view that central cholinergic stimulation provoking sympathoexcitation may be mediated by bulbospinal neurons. A rich plexus of varicose fibers overlapping the C7 area of RVL, which provides the excitatory drive for tonic sympathetic discharge, may form the anatomical basis for the increases in sympathetic nerve activity provoked by systemic or central administration of cho

ISSN:0092-7317    

DOI:10.1002/cne.902920102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe size of the lumbar and thoracic dorsal root ganglion cell populations in normally developing newly metamorphosedXenopus laeviswere measured in order to determine whether these neuron populations have the same characteristics as the hindlimb motoneuron population; i. e., large individual as well as sibling group differences, striking bilateral symmetry, and a rough correspondence between neuron number and body size that suggests some peripheral control of cell number during normal development (Sperry, J. Comp. Neurol. 264:250‐267). Among animals from three sibling groups, the total numbers of thoracic and lumbar ganglion cells are highly variable and symmetrical, although symmetry is not uniformly present at the level of individual ganglion pairs. Significant sibling group differences in neuron number are also present. Metamorphic body size and cell number in the thoracic but not in the lumbar ganglia are significantly correlated. The motoneurons innervating the hindlimbs were also counted and measured in the same animals. While variable as well as symmetrical, motoneuron number and metamorphic body size are correlated in only two of the three sibling groups. Interestingly, the numbers of motoneurons and lumbar ganglion cells, two populations of neurons whose sizes one might predict would be significantly correlated in normally developing animals, are not correlated. The relationship between these observations and currently held views concerning how neuron numbers might be controlled during normal development is discusse

ISSN:0092-7317    

DOI:10.1002/cne.902920103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe distribution of olfactory fibers in the brain of the three‐spined stickleback was visualized by means of immunohistochemistry. The labeling of the olfactory fibers was produced by serum containing antibodies against somatostatin‐14. Olfactory fibers were observed entering the olfactory bulbs, where they terminated in the glomerular layer or collected into fascicles that coursed through the bulbs into the telencephalon without participating in the formation of the glomerules. In the telencephalon the fascicles, which belonged to the medial olfactory tract, formed two fiber systems: ventral descending fibers and dorsal descending fibers. The ventral descending fibers could be followed through the ventral telencephalon to the vicinity of the lateral tuberal nucleus. The dorsal descending fibers coursed via the anterior commissure to the posterior part of the telencephalon. Part of the postcommissural fibers of the dorsal descending system coursed to the posterior zone of the area dorsalis telencephali while others left the telencephalon via the medial forebrain bundle and could be followed to the periventricular hypothalamus. Some axons formed synaptic contacts with unlabeled cell bodies in the nucleus of the terminal nerve which, in this species, is situated immediately behind the bulbs. In addition, an extensive terminal field associated with the dorsal descending fibers was found in the ventromedial aspects of the telencephalon.It is unlikely that the labeling represents immunoreactive somatostin‐14 because: 1) the labeling persisted after the absorption of the antiserum with synthetic somatostatin‐14; 2) antiserum against somatostatin‐14 from another manufacturer did not have this labeling property; and 3) the production of the absorbable labeling depended on the choice of fixative whereas the production of the unabsorbable labelin

ISSN:0092-7317    

DOI:10.1002/cne.902920104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractPhotoreceptor cells in the pineal complex of poikilothermic vertebrates are regarded as homologous with the neuroendocrine pinealocytes in the mammalian pineal organ. They possess an indolamine metabolism, and they contain a number of substances that are immunochemically similar to phototransduction‐related proteins otherwise found in photoreceptors of the lateral eye retina. Using correlative light and electron microscopic pre‐embedding immunocytochemistry, we have identified photosensory and neural elements that are immunoreactive with specific antisera against serotonin (5‐hydroxytryptamine) and the 48 kDa soluble protein S‐antigen (arrestin). One type of serotonin‐immunoreactive (5HTir) photoreceptor cell was identified. This was characterized by a short basal pole, into which an immunoreactive (postsynaptic?) element protruded. Two types of ‐antigen‐immunoreactive (SAir) photoreceptor cells were observed, one characterized by a short basal pole, similar to that of the 5HTir photoreceptors and the other characterized by a long, extensively branching basal pole. In addition, two types of neurons bearing no morphological specializations typical of photoreceptor cells were SAir: bipolar neurons and multipolar neurons. These were often situated dorsally in the pineal organ. The results indicate an emergence of multiple lines of photoreceptor‐derived “pinealocytes” either early in phylogeny, or independently in different taxa. The results are discussed in relation to current theories

ISSN:0092-7317    

DOI:10.1002/cne.902920105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe goal of this study was to determine whether somatosensory thalamic nuclei other than the ventroposterior nucleus proper VP have connections with area 3b of the postcentral cortex in squirrel monkeys. Small injections of the anatomical tracers wheat germ agglutinin conjugated to horseradish peroxidaseWGA‐HRP or H‐proline were placed in electrophysiologically identified representations of body parts. The results indicate that, besides the well‐established somatotopically organized connections with VP, area 3b has connections with three other nuclei of the somatosensory thalamus: the ventroposterior superior nucleus VPS [“shell” of VP], the ventroposterior inferior nucleus VPI, and the anterior pulvinar nucleus Pa. Injections confined to area 3b or involving adjacent parts of area 3a or area 1 indicate that connections between VPS, VPI, and Pa and the postcentral cortex are somatotopically organized. In VPS, connections related to the hand were found medially, and connections related to the foot were lateral. In VPI, connections with the cortical representations of the mouth, hand, and foot were successively more lateral. In Pa, connections related to the mouth, hand and foot were successively more ventral, lateral, and caudal, and the trunk region was caudomedial. The findings suggest that VPI contains a representation of all parts of the body, including the face. The connections of Pa with the primary somatosensory cortex, area 3b, the location of Pa relative to the ventroposterior nucleus, and the high degree of topographic order in the connections of Pa with the postcentral cortex suggest that Pa is an integral part of the somatosensory thalamus in monkeys and is homologous to the medial nucleus of the posterior group Pom in other mammals. Overall, the results contribute to the growing evidence that individual somatosensory cortical areas in monkeys receive inputs from multiple thalamic sources, and that a single thalamic nucleus has several cortica

ISSN:0092-7317    

DOI:10.1002/cne.902920106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe noncorpuscular endings (“free nerve endings”) of thinly myelinated group III and nonmyelinated group IV afferent nerve fibers have been examined in the knee joint capsule of sympathectomized cats by transmission electron microscopy and three‐dimensional reconstruction of series of semi‐ and ultrathin sections. The sensory ending is the most distal part of a group III or IV nerve fiber that consists only of the sensory axon and associated Schwann cells butlacks a myelin sheath and is not surrounded by perineurium. The sensory axon divides into several branches and forms a terminal tree. The branches run either as single fibers or within small Remak bundles in parallel to sensory axons of other endings; they spread along vessel walls and also extend into dense connective tissue. Each sensory axon consists of a series of spindle‐shaped thick segments “beads” connected by waist‐like thin segments. Thus all axons of sensory endings have a string‐of‐beads appearance, which resembles that of efferent sympathetic nerve fibers. The beads of the sensory axon and the end bulb at its tip show the same ultrastructural features which are characteristic of receptive sites: an accumulation of mitochondria and glycogen particles and various vesicles in the axoplasm and “bare” areas of axolemma that are not covered by Schwann cell processes. Group III and group IV sensory endings differ in the length of their branches up to 200 μm in group III vs. more than 300 μm in group IV, number of beads per 100 μm axon length about seven vs. nine or ten, mean diameter of axons 0.9‐1.5 μm vs. 0.3‐0.6 μm, and the presence of a neurofilament core consisting of bundles of parallel microfilaments only in group III. In conclusion, we propose that the sensory part of noncorpuscular “free nerve endings” is formed by the entire terminal tree of group III or group IV nerve fibers and that the beads in the course of the sensory axo

ISSN:0092-7317    

DOI:10.1002/cne.902920107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effect of protein deprivation on rapid Golgi impregnated pyramidal neurons in layers II/III and V of the rat visual cortex was studied at 30, 90, and 220 days of age using morphometric methods. In order to mimic human undernutrition female rats were adapted to either an 8% or control 25% casein diet 5 weeks prior to conception and maintained on these diets during gestation and lactation. The pups were then weaned and maintained on their respective diets. The undernourished rats showed a significant decrease in brain weight only at 90 days, indicating that the protein deprivation had a mild effect on brain development. Crrespondingly, the number of significant histological differences between the two diet groups were least at 30 and 220 days of age. The effect of the diet was greater on layer V than on layer II/III pyramids. At 30 days of age the effect of the diet was different on the pyramids of these two cell layers, at 90 days there was a mixture of similar and dissimilar effects, and at 220 days the pyramids of these two cell layers showed only minor differences between the two diet groups. Analysis of age‐related changes indicated that the effect of the diet was different on layer II/III pyramids compared to layer V pyramidal cells. These different effects apparently accounted for the progression from a dossimilar effect of the diet at 30 days on the pyramids of the two cell layers to only minor differences between them at 220 days. Further analysis of these age‐related changes shows that two prominent effects of protein deprivation are for age‐related changes to occur in undernourished rats but not in controls and for age‐related changes to be out‐of‐phase with each other in the two diet groups. From these findings, and a review of similar studies in the literature, we propose that these mechanisms are a prominent effect of undernutrition in the post‐weaning period and help account for the unexpected increases in morphometric measurements noted in undernourished rats in this and

ISSN:0092-7317    

DOI:10.1002/cne.902920108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe localization of catecholamines (CA) in the brain ofApteronotus leptorhynchuswas studied with immunohistochemical techniques using antibodies to the enzymes tyrosine hydroxylase (TH), dopamine B‐hydroxylase (DBH), phenylethanolamine‐N‐methyltransferase (PNMT), and the neurotransmitter dopamine (DA). Telencephalic TH and DA immunoreactive (ir) neurons were located in the following structures: olfactory bulb, area ventralis telencephali partes ventralis, centralis, dorsalis, and intermediate. Diencephalic TH ir neurons were distributed in: nucleus preopticus periventricularis pars anterior, floor of preoptic recess, n. suprachiasmaticus, n. preopticus periventricularis pars posterior, n. anterior periventricularis, area ventralis lateralis, rostral region of posterior periventricular nucleus (paraventricular organ of other authors), periventricular nucleus of posterior tuberculum, n. recessus lateralis, n. tuberis lateralis pars anterior, and n. tuberis posterior.Although most diencephalic TH ir structures were also DAir, the posterior periventricular nucleus, n. recessus lateralis pars medialis, n. recessus posterioris, and ventral region of nucleus lateralis tuberis pars anterior showed differences in the distribution of TH and DA immunoreactivity.The rhombencephalic structures contained cell groups with different combinations of catecholamines as follows: TH and DBH ir neurons in the isthmic tegmentum (locus coeruleus); TH and DBH ir cells in the rostral medullary tegmentum ventral to VIIth nerve; TH and PNMT ir cells in the sensory nucleus of the vagus nerve; TH, DBH, and PNMT ir cells in the dorsal medullary tegmentum, TH and DBH ir cells in the dorsomedian postobecular region, ventral to the descending trigeminal tract and lateral to the central canal at medullospinal levels. This study shows that: (1) with few exceptions TH and DA ir coincides, (2) gymnotiforms possess similar DBH ir rhombencephalic groups, but additional telencephalic and rhombencephalic TH ir groups, and PNMT ir cells that were not reported previously in teleosts, and (3) the presence of CAergic fibers in the electrosensory system supports findings of their modulatory funtion in communication and aggre

ISSN:0092-7317    

DOI:10.1002/cne.902920109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902920101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY