ISSN:0092-7317    

DOI:10.1002/cne.903390102

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

年代:1994

数据来源: WILEY

摘要:

AbstractTo achieve gene delivery to sensory neurons of the trigeminal ganglion, thymidine kinase‐negative (TK−) herpes simplex viruses (HSV) containing the reporter genelacZ(the gene forE. coliβ‐galactosidase) downstream of viral (in vectors RH116 andtkLTRZ1) or mammalian (in vector NSE‐lacZ‐tk) promoters were inoculated onto mouse cornea and snout.Trigeminal ganglia were removed 4, 14, 30, and 60 days after inoculation with vectors and histochemically processed with 5‐bromo‐4‐chloro‐3 indolyl‐beta‐galactoside (X‐Gal). With vectortkLTRZ1, large numbers of labeled neurons were observed in rostromedial and central trigeminal ganglion at 4 days after inoculation. A gradual decline in the number of labeled neurons was observed with this vector at subsequent time points. With vectors RH116 and NSE‐lacZ‐tk, smaller numbers of labeled neurons were seen at 4 days following inoculation than were observed with vectortkLTRZ1. No labeled neurons could be observed at 14 days after inoculation with vectors RH116 and NSE‐lacZ‐tk.Immunocytochemistry forE. coliβ‐galactosidase and in situ hybridization to HSV latency‐associated transcripts revealed labeled neurons in regions of the trigeminal ganglion similar to that observed with X‐Gal staining. A comparable distribution of labeled neurons in trigeminal ganglion was also observed after application of the retrograde tracer Fluoro‐Gold to mouse cornea and snout.These data provide evidence that retrogradely transported tk−herpes virus vectors can be used to deliver a functional gene to sensory neurons in vivo in an anatomically

ISSN:0092-7317    

DOI:10.1002/cne.903390103

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

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper presents a survey of the cell masses in the brainstem of the generalized actinopterygian fishAmia calva, based on transversely cut Nissl‐, Klüver‐Barrera‐, and Bodian‐stained serial sections. This study is intended to serve a double purpose. First it forms part of a now almost complete series of publications on the structure of the brainstem in representative species of all groups of vertebrates. Within the framework of this comparative program the cell masses in the brainstem and their positional relations are analyzed in the light of the Herrick–Johnston concept; according to this the brainstem nuclei are arranged in four longitudinal, functional zones or columns, the boundaries of which are marked by ventricular sulci. The procedure employed in this analysis essentially involves two steps: first, the cell masses and large individual cells are projected upon the ventricular surface, and next, the ventricular surface is flattened out, that is, subjected to a one‐to‐one continuous topological transformation (Nieuwenhuys [1974] J. Comp. Neurol. 156:255‐267). The second purpose of the present paper is to provide a cytoarchitectonic basis for experimental analysis of the fiber connectivity in the brainstem ofAmia.Five longitudinal sulci–the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, the sulcus intermedius dorsalis, and the sulcus lateralis mesencephali–could be distinguished. Some shorter grooves, present in the isthmal region, clearly deviate from the overall longitudinal pattern of the other sulci. Although inAmiamost neuronal perikarya are contained within a diffuse periventricular gray, 40 cell masses could be delineated: Eight of these are primary efferent or motor nuclei, 10 are primary afferent or sensory centers, seven are considered to be components of the reticular formation, and the remaining 15 may be interpreted as “relay” nuclei.The topological analysis yielded the following results. In the rhombencephalon the gray matter is arranged in four longitudinal columns or areas, termed area ventralis, area intermedioventralis, are intermediodorsalis, and area dorsalis. The sulcus intermedius ventralis, the sulcus limitans, and the sulcus intermedius dorsalis mark the bounderies between these morphological entities. These longitudinal areas coincide largely, but not entirely, with the functional columns of Herrick and Johnston. The most obvious incongruity is that the area intermediodorsalis contains, in addition to the viscerosensory nucleus of the solitary tract, several general somatosensory and special somatosensory nuclei. The four longitudinal zones cannot be distinguished in the mesencephalon nor can the sulcus limitans be recognized here. Functionally, however, the medial part of the tegmentum mesencephali may be considered the rostral extremity of the somatomotor column, whereas the remainder of the midbrain contains a number of somatosensory centers

ISSN:0092-7317    

DOI:10.1002/cne.903390104

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

年代:1994

数据来源: WILEY

摘要:

AbstractSecond‐order auditory neurons in nucleus magnocellularis (NM) of the chick brainstem undergo a series of rapid metabolic changes following unilateral cochlea removal, culminating in the death of 25% of NM neurons. Within hours of cochlea removal, ipsilateral NM neurons show marked increases in histochemical staining for the mitochondrial enzymes succinate dehydrogenase and cytochrome oxidase. We investigated corresponding ultrastructural changes in NM neurons by preparing animals undergoing unilateral cochlea removal for transmission electron microscopy. We quantified changes in NM mitochondrial volume by stereological methods and qualitatively compared mitochondrial morphology between NM neurons destined to survive and those destined to die after cochlea removal.Within hours of cochlea removal, ipsilateral NM neurons show striking increases in mitochondrial volume (84% at 12 hours and 236% at 12 hours after cochlea removal compared to unoperated, control animals). At 2 week survival times, ipsilateral NM neurons contain fewer mitochondria than contralateral neurons. Surprisingly, anesthesia alone causes short‐term increases in NM mitochondrial volume. Animals anesthetized with pentobarbital and ketamine and sacrificed 6 or 12 hours later showed a 45% increase in mitochondrial volume compared to previously unanesthetized animals. NM neurons destined to die within days of cochlea removal can be identified within several hours after deafferentation by the appearance of their ribosomes. We observed qualitative differences in mitochondrial morphology in dying neurons. Mitochondria in neurons destined to die consistently showed mitochondrial swelling and vacuolization indicative of metabolic dysfunction. Similar mitochondrial changes have been reported when mitochondria take up excess calcium. Ultrastructural changes in NM after cochlea removal display features of both programmed and pathological cell death, in which increased intracellular calcium is thought to play a role. © 1994 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903390105

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

年代:1994

数据来源: WILEY

摘要:

AbstractIn order to determine the regions within the parabrachial nucleus that receive synaptic input from nociceptive regions of the spinal cord and medulla in the rat, we analyzed the “Golgi‐like” labeling produced by anterograde transport ofPhaseolus vulgarisleucoagglutinin (PHA‐L) from discrete iontophoretic injections confined to either the superficial dorsal horn of the lumbar spinal cord or to the superficial dorsal horn of the trigeminal nucleus at the level of the obex. Labeled fibers from both the spinal cord and the medulla ascended through the ventral lateral pons and coursed with the ventral spinocerebellar tract toward the parabrachial nuclei. Spinal cord injections led to labeling of fine caliber fibers and en passant and terminal enlargements in the rostral part of the contralateral lateral parabrachial nucleus (PBL), mostly in the central lateral and dorsal lateral subnuclei. Medullary injections revealed fiber and enlargement labeling primarily in the ipsilateral caudal PBL, mostly in the central lateral, external lateral, and medial subnuclei. Injections in both regions resulted in labeled terminations in the Kö;lliker‐Fuse nucleus. These results indicate that the nociceptive regions of the spinal cord and medulla terminate in regions of the parabrachial nucleus that have been associated with autonomic functions because of their interconnections with the hypothalamus, brainstem cardiovascular and respiratory control centers, and the amygdala. © 1994 Wile

ISSN:0092-7317    

DOI:10.1002/cne.903390106

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe distribution of NADPH‐d activity in the spinal cord and dorsal root ganglia of the cat was studied to evaluate the role of nitric oxide in lumbosacral afferent and spinal autonomic pathways. At all levels of the spinal cord NADPH‐d staining was present in neurons and fibers in the superficial dorsal horn and in neurons around the central canal and in the dorsal commissure. In addition, the sympathetic autonomic nucleus in the rostral lumbar segments exhibited prominent NADPH‐d cellular staining whereas the parasympathetic nucleus in the sacral segments was not well stained. The most prominent NADPH‐d activity in the sacral segments occurred in fibers extending from Lissauer's tract through laminae I along the lateral edge of the dorsal horn to lamina V and the region of the sacral parasympathetic nucleus. These fibers were very similar to VIP‐containing and pelvic nerve afferent projections in the same region. They were prominent in the S1–S3segments but not in adjacent segments (L6–L7and Cx1) or in thoracolumbar and cervical segments. NADPH‐d activity and VIP immunoreactivity in Lissauer's tract and the lateral dorsal horn were eliminated or greatly reduced after dorsal‐ventral rhizotomy (S1–S3), indicating the fibers represent primary afferent projections. A population of small diameter afferent neurons in the L7–S2dorsal root ganglia were intensely stained for NADPH‐d. The functional significance of the NADPH‐d histochemical stain remains to be determined; however, if NADPH‐d is nitric oxide synthase then this would suggest that nitric oxide may function as a transmitter in thoracolumbar sympathetic preganglionic efferent pathways and in sacral parasympathetic afferent pathways in the

ISSN:0092-7317    

DOI:10.1002/cne.903390107

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

年代:1994

数据来源: WILEY

摘要:

AbstractTwo neuron types contact the Mauthner cell (M cell) in the axon cap, a specialized region of high electrical resistance surrounding the initial segment of the M cell axon. One type produces a mixed electrical and chemical inhibition of the M cell. The second sends axons into the central core of the axon cap, where they spiral around the initial segment making both conventional synapses and gap junction contacts. The origin and synaptic effects of these spiral fibers have not been studied previously.When goldfish M cells were filled with Lucifer yellow, presynaptic spiral fibers were seen in the axon cap. These fibers could be traced back through the medial longitudinal fasciculus to their somata, near the contralateral fifth nerve motor nucleus. The same somata were labeled by horseradish peroxidase injected extracellularly into the axon cap.Recordings were made in the axon cap and the M cell after stimulation of hindbrain areas near the spiral fiber somata and axons. Extracellularly, a negative potential was observed close to the termination of the spiral fibers and termed the spiral fiber potential (SFP). Intracellularly, a graded, short latency depolarization of the M cell corresponded to the SFP and could cause the M cell to spike. This depolarization did not shunt the membrane, indicating that it may be produced through gap junctions. Intracellular responses to hindbrain stimulation also had a chloride‐dependent, second component that shunted the membrane during paired‐pulse testing. This inhibitory second component was probably evoked by cells other than the spiral fiber cells themselves. © 1994 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903390108

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

年代:1994

数据来源: WILEY

摘要:

AbstractAccumulating evidence indicates that the insulin‐like growth factors (IGFs) can act as neurotrophic factors. A family of at least six IGF binding proteins (IGFBPs) has been characterized. The IGFBPs prolong the half‐life of IGFs in plasma and may modulate IGF action in a cell‐ or tissue‐specific fashion. Two recently characterized IGFBPs, IGFBP‐4 and ‐5, have been shown by northern blot hybridization to be expressed in rat brain, but their cellular sites of synthesis are poorly characterized. Because IGFBP‐4 and IGFBP‐5 could potentially modulate IGF actions in the brain, we used in situ hybridization histochemistry and35S‐labeled IGFBP‐4 and IGFBP‐5 riboprobes to localize sites of IGFBP‐4 and ‐5 mRNA expression in adult rat brain. The two IGFBP mRNAs are abundantly expressed within discrete regions of brain. The expression patterns of the two genes are largely nonoverlapping. Notably, IGFBP‐4 mRNA is highly expressed within hippocampal and cortical areas, whereas IGFBP‐5 mRNA is not detected above background in these areas. Within the hippocampus, abundant IGFBP‐4 mRNA expression is detected in pyramidal neurons of the subfields of Ammon's horn and the subiculum and in the granule cell layer of the anterior hippocampal continuation. In the cortex, IGFBP‐4 mRNA is widely expressed in most areas and layers. In contrast, IGFBP‐5, but not IGFBP‐4, mRNA is detected within thalamic nuclei, leptomeninges, and perivascular sheaths. The distinct expression patterns of IGFBP‐4 and ‐5 mRNAs within the brain suggest that these IGFBPs may modulate paracrine/autocrine actions of the IGFs in discrete brain regions or compartmentalization of the IGFs

ISSN:0092-7317    

DOI:10.1002/cne.903390109

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

年代:1994

数据来源: WILEY

摘要:

AbstractPrevious investigators have documented the postnatal development of alpha and beta type ganglion cells in cat retinae (Ramoa et al. [1987] Science 237:522–525; Ramoa et al. [1988]J. Neurosci. 8:4239–4261; Dann et al. [1987] Neurosci. Lett. 80:21–26; Dann et al. [1988]J. Neurosci. 8(5):1485–1499). The development of the remaining cells (about 50%), which constitute a heterogeneous group and are referred to here collectively as gamma cells (Boycott and Wässle, '74), has not been studied in detail. The purpose of this study was to compare the postnatal development of alpha, beta, and gamma cells in kitten and adult retinae using horseradish peroxidase histochemistry and the fluorescent dye Dil. In the kitten, alpha, beta, and gamma cells are recognizable. We find, as have others, that kitten alpha and beta cell bodies and dendritic fields are significantly smaller than in the adult. However, kitten gamma cells are nearly adult sized. In fact, at birth the cell bodies of beta cells throughout the retina are significantly smaller than those of gamma cells. During the first 12 weeks of life, alpha and beta cell bodies increase in size from 90% to 680% depending upon eccentricity. Gamma cells hardly increase in size at all. Also, the normal adult center‐to‐peripheral cell size gradient for alpha and beta cells is not seen in the neonate. Gamma cells show no such gradient in the neonate or adult. Our results suggest that the morphological development of alpha and beta cells occurs later than that of gamma cells and may explain some of the differences in the effects of visual deprivation and surgical manipulation upon the parallel Y‐, X‐, and W‐cell pathways. © 1

ISSN:0092-7317    

DOI:10.1002/cne.903390110

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

年代:1994

数据来源: WILEY

摘要:

AbstractMany conditions are thought to contribute to neuron death after axotomy, including immaturity of the cell at the time of injury, inability to reestablish or maintain target contact, and dependence on trophic factors produced by targets. Exogenous application of neurotrophic factors and transplants of peripheral nerve and embryonic central nervous system (CNS) tissue temporarily rescue axotomized CNS neurons, but permanent rescue may require transplants that are normal targets of the injured neurons. We examined the requirements for survival of axotomized Clarke's nucleus (CN) neurons. Two months after hemisection of the spinal cord at the T8 segment, there was an ipsilateral 30% loss of neurons at the L1 segment in adult operates and a 40% loss in neonates. Transplants of embryonic spinal cord, cerebellum, and neocortex inserted into the T8 segment at the time of hemisection prevented virtually all of the cell death in both adults and neonates, but transplants of embryonic striatum were ineffective. None of the grafts prevented the somal atrophy of CN neurons caused by axotomy. Retrograde transport of fluoro‐gold from the cerebellum demonstrated that 33% of all CN neurons at L1 project to the cerebellum, 50% of these died following a T8 hemisection, but all these projection neurons were rescued by a transplant of embryonic spinal cord. These results suggest that the rescue of axotomized CN neurons is relatively specific for the normal target areas of these neurons, but this specificity is not absolute and may depend on the distribution and synthesis of particular neurotrophic agents. © 1994 Wiley‐Liss,

ISSN:0092-7317    

DOI:10.1002/cne.903390111

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

年代:1994

数据来源: WILEY