摘要:

AbstractLungfishes possess two cranial nerves that are associated with the olfactory system: the nervus terminalis enters the telencephalon with the olfactory nerve, and the nervus praeopticus enters the diencephalon at the level of the optic nerve. We investigated the central projections of the nervus terminalis and the nervus praeopticus in the Australian lungfish (Neoceratodus forsteri) and in the African lungfish (Protopterus dolloi) by NADPH‐diaphorase histochemistry (nitric oxide synthase; NOS) and compared them with the projections of the nervus terminalis of the frog (Xenopus laevis).InNeoceratodus, NOS‐positive fascicles of the nervus terminalis divide and project with a ventral component through the septum and with a dorsal component through the pallium; fibers of both trajectories extend caudally beyond the anterior commissure and join the lateral forebrain bundle. In the nervus praeopticus, about 300 fibers contain NOS; they innervate the preoptic nucleus and continue their course through the diencephalon; many fibers cross in the commissure of the posterior tuberculum.InProtopterus, ganglion cells of the nervus terminalis and of the nervus praeopticus contain NOS. NOS‐positive fibers of the nervus terminalis project through the septal region but not through the pallium. Several major fascicles cross in the rostral part of the anterior commissure, where they are joined by a small number of NOS‐containing fibers of the nervus praeopticus. Both nerves innervate the preoptic nucleus. The number and pathways of the fascicles of the nervus terminalis are not always symmetric between the two sides. The nervus terminalis fascicles remain in a ventral position, whereas the nervus praeopticus gives rise to the more dorsal fascicles. Many fibers of the two nerves extend throughout the diencephalon and cross in the commissure of the posterior tuberculum.These findings demonstrate many similarities but also significant differences between the contributions of the nervus terminalis and the nervus praeopticus to forebrain projections in the two lungfishes. They support the view that the nervus praeopticus is part of a nervus terminalis system comparable to that in frogs and other nonmammalian vertebrates. © 1994 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903490102

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

年代:1994

数据来源: WILEY

摘要:

AbstractNeurotrophins such as nerve growth factor (NGF) mediate their effects through interactions with high‐affinity tropomycin‐related kinase (trk) receptors. The present study employed a polyclonal antibody to characterize the distribution of trk‐immunoreactive neurons within the nonhuman primate brain. Both young adult and aged cebus and rhesus monkeys displayed trk‐immunoreactive neurons within all subdivisions of the basal forebrain. Colocalization studies revealed that between 66% and 76% of trk‐immunoreactive basal forebrain neurons also expressed immunoreactivity for the low‐affinity p75 NGF receptor, an excellent marker for cholinergic basal forebrain cells. In this experiment, most single‐labeled basal forebrain neurons contained only trk immunoreactivity, whereas 4% of basal forebrain neurons expressed only the low‐affinity p75 NGF receptor. Scattered trk‐immunoreactive neurons also were observed within the caudate nucleus and putamen. Although dual‐localization studies with choline acetyltransferase (ChAT) were not performed, striatal neurons codistributed with ChAT‐immunoreactive cells, and both types of cells were similar in size and morphology. This suggests that trk immunoreactivity is expressed within cholinergic interneurons within the primate striatum. Finally, lightly stained trk‐immunoreactive neurons were observed within the stratum oriens of the hippocampal formation and within the hypothalamus. These data indicate that both cholinergic and, possibly, noncholinergic forebrain neurons express the protein for the high‐affinity trk receptor, which transduces the signal mediating the trophic effects of neurotrophins. In addition, the pattern of trk immunoreactivity was preserved in two aged (26 and 29 years old) rhesus monkeys, suggesting that the expression of trk, for the most part, is sustained throughout the lifetime of the organis

ISSN:0092-7317    

DOI:10.1002/cne.903490103

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

年代:1994

数据来源: WILEY

摘要:

AbstractAlthough the nucleus tractus solitarii (NTS) has been established as the primary site of synaptic integration for the baroreceptor reflex, the higher‐order pathways responsive to, and mediating, changes in vasomotor tone are not well characterized. We used immunohistochemistry to determine the distribution of cells expressing the Fos protein follwing pharmacologically induced, directionally specific changes in arterial pressure. The goal of this investigation was to determine if this immediate early gene product is differentially expressed in neurons of the rat brainstem follwing increased (pressor) versus decreased (depressor) arterial blood pressure (AP). Because brainstem catecholaminergic (CA) cell groups have been implicated in cardiovascular regulation, a double‐labeling immunohistochemical procedure was used to examine the distribution of Fos in CA cells.Animals received continuous intravenous infusion of either a vasoconstrictor (l‐phenylephrine hydrochloride), a vasodilator (sodium nitroprusside), or physiological saline. Extensive Fos‐like immunoreactivity (FLI) was induced in both the pressor and depressor conditions in the NTS, caudal ventrolateral medulla (CVLM), rostral ventrolateral medulla (RVLM), A5, locus coeruleus (LC), Kolliker‐Fuse, and parabrachial nucleus (PBN). These regions have all been implicated in central cardiovascular regulation. There were differences in the anatomical distribution of Fos‐positive cells along the rostrocaudal axis of CVLM in the pressor and depressor conditions. Specifically, increased AP induced significantly more FLI cells within the rostral aspects of CVLM, whereas decreased AP resulted in a significantly greater number of FLI cells within the caudal CVLM. This result suggests that selective vasomotor responses differentially engaged discrete subsets of neurons within this brainstem region.Overall, approximately 50% of CA‐immunoreactive cells were also FLI (CA‐FLI) in the A1, A5, and A7 regions. Interestingly, increased AP produced significantly more CA‐FLI doublelabeled cells within the caudal than rostral A1 compared with depressor and control groups. Additionally, increased AP yielded significantly less CA‐FLI double‐labeled cells within the caudal A2 region. This suggests that CA barosensitive neurons in the CVLM/A1 and NTS/A2 regions are functionally segregated along the rostrocaudal axis of these structures. While twice as many PNMT‐FLI double‐labeled neurons were found in the C1–C3 regions following vasomotor changes versus saline control, there were no differences in the numbers or anatomical locations of labeled cells between pressor versus depressor groups. The results of this study indicate that (1) tonic changes in AP induce robust Fos expression in brainstem cardiovascular areas and (2) neurons responsive to specific directional changes in arterial pressure are segregated in some brainstem regi

ISSN:0092-7317    

DOI:10.1002/cne.903490104

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe cerebellum plays an important role in the visual guidance of movement. In order to understand the anatomical basis of visuomotor control, we studied the projection of pontine visual cells onto the cerebellar cortex of monkeys. Wheat germ agglutinin horseradish peroxidase was injected into the dorsolateral pons of two monkeys. Retrogradely labelled cells were mapped in the cerebral cortex and superior colliculus, and orthogradely labelled fibers in the cerebellar cortex. The largest number of retrogradely labelled cells in the cerebral cortex was in a group of medial extrastriate visual areas. The major cerebellar target of these dorsolateral pontine cells is the dorsal paraflocculus. There is a weaker projection to the uvula, paramedian lobe, and Crus II, and a sparse but definite projection to the ventral paraflocculus. There are virtually no projections to the flocculus. There are sparse ipsilateral pontocerebellar projections to these same regions of cerebellar cortex.In nine monkeys, we made small injections of the tracer into the cerebellar cortex and studied the location of retrogradely filled cells in the pontine nuclei and inferior olive. Injections into the dorsal paraflocculus or rostral folia of the uvula retrogradely labelled large numbers of cells in the dorsolateral region of the contralateral pontine nuclei. Labelled cells were found ipsilaterally, but in reduced numbers. Injections outside of these areas in ventral paraflocculus or paramedian lobule labelled far fewer cells in this region of the pons. We conclude that the principal source of cerebral cortical visual information arises from a medial group of extrastriate visual areas and is relayed through cells in the dorsolateral pontine nuclei. The principal target of pontine visual cells is the dorsal paraflocculus. © 1994 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903490105

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

年代:1994

数据来源: WILEY

摘要:

AbstractGalanin is a brain‐gut peptide present in the central nervous system of fish, amphibians, birds, and mammals. For comparative studies among vertebrates, the distribution of galanin in the brain of reptiles has been investigated. We studied the localization of galanin‐like‐immunoreactive perikarya and nerve fibers in the brain of the turtleMauremys caspicaby using an antiserum against porcine galanin. In the telencephalon, few immunoreactive perikarya were seen in the amygdaloid complex. The diencephalon contained the majority of the immunoreactive perikarya present in the lamina terminalis, nucleus periventricularis anterior, lateral preoptic area, nuclei hypothalamicus ventromedialis and posterior, nucleus basalis of the anterior commissure, and nucleus ventralis tuberis. Many immunoreactive cells, especially in the infundibulum, contacted the cerebrospinal fluid by an apical process. In the rhomben‐cephalon, immunopositive perikarya were restricted to a few cells in the nucleus tractus solitari. In the mesencephalon, they were absent. Immunoreactive nerve fibers were present in all regions containing labeled perikarya and in (1) telencephalon: septum, nucleus fasciculi diagonalis Brocae; (2) diencephalon: nucleus paraventricularis, nucleus supraopticus, nucleus suprachiasmaticus, subventricular grey, nucleus of the paraventricular organ, nucleus mamillaris, infundibular decussation, outer layer of the median eminence, posterior commissure and subcommissural organ region, habenula, nuclei dorsomedialis anterior, and dorsolateralis anterior of the thalamus; and (3) mesencephalon and rhombencephalon: stratum griseum periventriculare, stratum fibrosum periventriculare, laminar nucleus of the torus semicircularis, periventricular grey, nucleus interpeduncularis, nucleus ruber, substantia nigra, locus coeruleus, raphe nuclei, nuclei of the reticular formation, nucleus motorius nervi trigemini, cochlear and vestibular area, and nucleus spinalis nerve trigemini. Our results suggest that galanin may have hypophysiotropic and central roles in the turtleMauremys caspica. © 1994 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903490106

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

年代:1994

数据来源: WILEY

摘要:

AbstractKainate receptors are found throughout many regions of the brain and presumably contribute to responses of neurons to glutamate and other excitatory amino acids. Two affinity‐purified polyclonal antibodies that recognize the kainate binding subunits, KA2 and GluR6, were made using C‐terminus peptides. A previous study demonstrated that each antibody is specific for its subunit, although antibody to GluR6 recognizes GluR7 to some extent (hence the designation GluR6/7). Vibratome sections immunostained with either antibody showed light to moderate staining in many structures in the brain as well as in cervical spinal cord, dorsal root and vestibular ganglia, and pineal and pituitary glands. Moderate levels were seen in the olfactory bulb, cerebral cortex, caudate/putamen, and hypothalamus, whereas much of the thalamus was stained lightly. In the hippocampus, CA3 pyramidal cells were stained more densely than CA1 pyramidal cells—the difference more evident with antibody to GluR6/7. In addition, neuropilar staining was denset in the stratum lucidum of the CA3 region. In the brainstem, staining was moderate to moderately dense in a number of sensory, motor, and reticular nuclei. The moderately dense staining in the reticulothalamic nucleus and pontine nuclei with antibody to GluR6/7 may represent its recognition of GluR7. In the cerebellum, staining was moderate in granular and molecular layers with antibody to KA2 and in the molecular layer with antibody to GluR6/7, whereas it was moderately dense to dense in the granular layer with the GluR6/7 antibody. Outside of the brain, densest staining was seen localization of immunostaining was examined in the hippocampus, cerebral cortex, and cerebellar cortex. Typically, major staining was in postsynaptic densities apposed by unstained presynaptic terminals with round or mainly round vesicles and in associated dendrites. The light microscope pattern of staining was fairly similar to that of previous [3H]kainate binding and in situ hybridization studies. In addition, comparision with previous studies on distribution of other types of glutamate receptors indicates that KA2 and GluR6/7 are found with various other subunits in many of the same cell populations throughout the nervous system. © 1994 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903490107

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe pretectal nucleus of the optic tract (NOT) plays an essential role in optokinetic nystagmus, the reflexive movements of the eyes to motion of the entire visual scene. To determine how the NOT can influence structures that move the eyes, we injected it with lectin‐conjugated horseradish peroxidase and characterized its afferent and efferent connections. The NOT sent its heaviest projection to the caudal half of the ipsilateral dorsal cap of Kooy in the inferior olive. The rostral dorsal cap was free of labeling. The NOT sent lighter, but consistent, projections to other visual and oculomotor‐related areas including, from rostral to caudal, the ipsilateral pregeniculate nucleus, the contralateeral NOT, the lateral and medial terminal nuclei of the accessory optic system bilaterally, the ipsilateral dorsolateral pontine nucleus, the ipsilateral nucleus prepositus hypoglossi, and the ipsilateral medial vestibular nucleus. The NOT received input from the contralateral NOT, the lateral terminal nuclei bilaterally, and the ipsilateral pregeniculate nucleus. Although our injections involved the pretectal olivary nucleus (PON), there was neither orthograde nor retrograde labeling in the contralateral PON. Our results indicate that the NOT can influence brainstem preoculomotor pathways both directly through the medial vestibular nucleus and nucleus prepositus hypoglossi and indirectly through both climbing and mossy fiber pathways to the cerebellar flocculus. In addition, the NOT communicates strongly with other retino‐recipient zones, whose neurons are driven by either horizontal (contralateral NOT) or vertical (medial and lateral terminal nuclei) fullfield image motion. © 1994 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903490108

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

年代:1994

数据来源: WILEY

摘要:

AbstractWe identified a ‘semicircular’ compartment of the rat thyropharyngeus muscle at the pharyngoesophageal junction and used the glycogen depletion method to determine how the fibers of this muscle (as well as all others of the pharynx and larynx) are innervated by different cranial nerve branches. The semicircular compartment appears anatomically homologous to the human cricopharyngeus muscle, an important component of the upper esophageal sphincter. While we found very little overlap in the muscle targets of the pharyngeal, superior laryngeal and recurrent laryngeal nerves within the pharynx and larynx, the semicircular muscle receives a dual, interdigitating innervation from two vagal branches: the pharyngeal nerve and a branch of the superior laryngeal nerve we call the dorsal accessory branch. After applying horseradish peroxidase to either of these two nerves, we compared the distribution and number of cells labeled in the brainstem. The dorsal accessory branch conveys a more heterogeneous set of efferent fibers than does the pharyngeal nerve, including the axons of pharyngeal and esophageal motor neurons and parasympathetic preganglionic neurons. The observed distribution of labeled motor neurons in nucleus ambiguus also leads us to suggest that the semicircular compartment is innervated by two subsets of motor neurons, one of which is displaced ventrolateral to the main pharyngeal motor column. This arrangement raises the possibility of functional differences among semicircular compartment motor neurons correlated with the observed differences in brainstem location of cell bodies. © 1994 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903490109

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

年代:1994

数据来源: WILEY

摘要:

AbstractBaby hamster kidney (BHK) cells were genetically modified to secrete high levels of human nerve growth factor (BHK‐hNGF). Following polymer encapsulation, these cells were implanted into the lateral ventricle of four cynomolgus monkeys immediately following a unilateral transection/aspiration of the fornix. Three control monkeys received identical implants, with the exception that the BHK cells were not genetically modified to secrete hNGF and thus differed only by the hNGF construct. One monkey received a fornix transection only. All monkeys displayed complete transections of the fornix as revealed by a comprehensive loss of acetylcholinesterase‐containing fibers within the hippocampus ipsilateral to the lesion. Control monkeys that were either unimplanted or received BHK‐control (non‐NGF secreting) cell implants did not differ from each other and displayed extensive losses of choline acetyltransferase and p75 NGF receptor (NGFr)‐immunoreactive neurons within the medial septum (MS; 53 and 54%, respectively) and vertical limb of the diagonal band (VLDB; 21 and 30%, respectively) ipsilateral to the lesion. In contrast, monkeys receiving implants of BHK‐hNGF cells exhibited a only a modest loss of cholinergic neurons within the septum (19 and 20%, respectively) and VLDB (7%). Furthermore, only implants of hNGF‐secreting cells induced a dense sprouting of cholinergic fibers within the septum, which ramified against the ependymal lining of the ventricle adjacent to the transplant site. Examination of the capsules retreived from monkeys just prior to their death revealed an abundance of cells that produced detectable levels of hNGF in a sufficient concentration to differentiate PC12A cells in culture. These findings support the use of polymer‐encapsulated cell therapy as a potential treatment for neurodegenerative diseases such as Alzheimer disease where basal forebrain degeneration is a consistent pathological feature. Moreover, this encapsulated xenogeneic system may provide therapeutically effective levels of a number of neurotrophic factors, alone or in combination, to select populations of neurons within the central nervous system. © 1994

ISSN:0092-7317    

DOI:10.1002/cne.903490110

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

年代:1994

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.903490101

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

年代:1994

数据来源: WILEY