摘要:

AbstractTwenty‐five specimens ofRana pipienswere subjected to a unilateral crush of the optic nerve. Substance P (SP)‐, leucine enkephalin (LENK)‐, cholecystokinin octapeptide (CCK8)‐, and bombesin (BOM)‐like immunoreactivities were analyzed in the retinae, optic nerves, and optic tecta, 9 days to 9 months postoperatively, by means of immunohistochemical methods. Peptide‐like immunoreactivity was observed in axons within the optic nerve stump retinal to the crush, as in previous studies (Kuljis and Karten, '83b, Kuljis et al., '84). Peptide‐containing retinofugal axons began traversing the lesion site between 10 and 20 days postoperatively, in progressively increasing numbers. Ten to 20 days following crush of the optic nerve SP‐, LENK‐, and CCK8‐containing axons could be found in the cerebral stump of the optic nerve and in the optic chiasm, advancing to the side of the brain deafferented by the crush. The number of axons displaying peptide‐like immunoreactivity within the optic nerve, retinal or cerebral to the crush, and within the optic chiasm gradually decreased after 2–3 months. The optic nerve contralateral to the procedure displayed only occasional isolated peptide‐containing fibers, as in normal optic nerves. The retinae ipsilateral and contralateral to the crush exhibited no change in the normal pattern of peptide‐like immunoreactivity, including the absence of demonstrable peptide‐like immunoreactivity in the somata of retinal ganglion cells.The optic tectum deafferented by the procedure underwent modifications in the pattern of peptide‐like immunoreactivity identical to those reported following unilateral eye enucleation (Kuljis and Karten, '82a, '83a). The patterns of LENK‐, CCK8‐, and BOM‐like immunoreactivities in the tectum were identical to those following irreversible retinal deafferentation as long as 9 months postoperatively. SP‐like immunoreactivity, however, was gradually restored in layer 11 of Ramón y Cajal ('46; layer D of Potter, '69) of the superficial (retinorecipient) neuropil 4–6 months postoperatively. The persistence of lamina‐specific depletion patterns of LENK‐, CCK8‐, and BOM‐like immunoreactivities in reafferented tecta represents a puzzling observation. The latter findings contrast sharply with the recovery of SP‐like immunoreactivity, which occurs long after apparently complete restitution of the retinofugal projection, as shown by anatomical (Stelzner et al., '81), physiological (Maturana et al., '59), and behavioral (Sperry, '44) methods. The implications of these findings are discussed with particular reference to (1) the possibility of lamina‐specific reinnervation of the tectum by SP‐containing retinofugal axons; (2) the possible roles of peptides in theadjustment or modulation of retinofugal input processing in the tectum; (3) the possibility of a differential capability for successful regeneration and/or specific reinnervation of the various populations of peptide‐containing retinal ganglion cells; and (4) the possibility of selective death of some of the peptide‐containing retinal ganglion cell populations as

ISSN:0092-7317    

DOI:10.1002/cne.902400102

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe principal goal of the present study was to determine the thalamic connections of area 2 of postcentral somatosensory cortex of monkeys. The placement of injections of anatomical tracers (horseradish peroxidase, wheat germ agglutinin, or3H‐proline) was guided by extensive microelectrode maps of cortex in the region of the injection site. These maps identified the body parts represented in the cortex included in the injection site, and provided information about the physiological boundaries of area 2, which was related later to the cortical architecture. Most injections were placed in the representation of the hand in area 2, which was highly responsive to cutaneous stimuli and could be mapped in detail. Injections were also placed in other parts of area 2, area 1, or area 5, and some injections involved more than one area.As other investigators have determined, regions of retrograde and anterograde thalamic label overlapped, demonstrating that connections with cortex are reciprocal. Injections completely confined to area 2 consistently produced label in two locations: the anterior pulvinar (Pa) and a dorsal capping zone of the ventroposterior complex that we term the ventroposterior superior nucleus (VPS). Single restricted injection sites resulted in one region of label in VPS, and multiple foci of label in Pa. In some cases where the injection was confined to the representation of the hand in area 2, label was also found more ventrally in the ventroposterior complex in ventroposterior nucleus proper (VP). Thus, area 2 receives input from Pa, VPS, and, at least in some locations and individuals, VP. Injections of tracers into area 1 confirmed previous findings that area 1 is densely interconnected with VP. In addition, there appear to be sparse connections with VPS. There was no evidence of connections with Pa. Evidence from injection sites that extended from area 2 into areas 5 and 7, and from injection sites in area 5, indicates that the lateral posterior nucleus (LP) projects to rostral areas 5 and 7.The results support the conclusion that area 2 is a functionally distinct subdivision of somatosensory cortex, and indicate that area 2 has thalamic connections that are characteristic of both “sensory” (VP and VPS) and “association” (Pa) cortic

ISSN:0092-7317    

DOI:10.1002/cne.902400103

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

年代:1985

数据来源: WILEY

摘要:

AbstractThese experiments were directed at determining the proportion and distribution of cholinergic septal cells which project to the rat hippocampal formation. Injections of WGA‐HRP were placed into different regions of the hippocampal formation and sections through the septal complex were processed for the simultaneous demonstration of the retrogradely transported marker and for choline acetyltransferase (ChAT) immunoreactivity. Preliminary analysis of adjacent normal series prepared either for the demonstration of ChAT or stained by the Nissl method demonstrated several distinct cell groups in the classically defined medial septal nucleus and vertical limb of the nucleus of the diagonal band. The groups of cells ranged from almost entirely ChAT‐positive to entirely noncholinergic. On the basis of shape and size of the constituent cells, the ChAT‐positive cells of the septal complex were divided into dorsal, intermediate, and ventral subdivisions.The proportion of retrogradely labeled cells that were also ChAT positive ranged from 22.8% to 77.4% in different experiments. When only the hippocampus and dentate gyrus are considered, this variation can largely be accounted for by the topographic organization of the septohippocampal projection. The medial, noncholinergic half of the medial septal nucleus projects primarily to the rostral or septal portions of the dentate gyrus and hippocampus, whereas the lateral half, in which the dorsal ChAT group is located, projects heavily to more temporal levels. Rostral portions of the hippocampus and dentate gyrus receive most of their cholinergic input from the ventral ChAT cell group which forms a major component of the vertical limb of the nucleus of the diagonal band. While some ChAT‐positive cells in the intermediate group project to the hippocampal formation, they are generally less numerous than those from the dorsal and ventral groups. However, in a control experiment in which the WGA‐HRP injection was placed into the cingulate cortex overlying the rostral hippocampal formation, the intermediate ChAT group accounted for 71.2% of the double‐la

ISSN:0092-7317    

DOI:10.1002/cne.902400104

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

年代:1985

数据来源: WILEY

摘要:

AbstractA number of recent experiments suggest that grafted dopaminergic neurons provide functional input to a host caudoputamen which previously had been deprived of its dopaminergic input. The purpose of the present study was to determine whether tyrosine hydroxylase immunoreactive processes which originate in the graft participate in morphologically identifiable synapses in the host neuropil.Prior to transplantation, adult Sprague‐Dawley rats received unilateral injections of 6‐hydroxydopamine into the medial forebrain bundle. Animals were screened for the success of striatal denervation by a test of apomorphine‐induced rotation. Transplants of fetal substantia nigra then were placed into cavities in the caudoputamen. After a 6–8 month survival period, animals were perfused and prepared for tyrosine hydroxylase immunocytochemistry. No evidence of sprouting of the host catecholoaminergic system was observed, even after long survival times.Both pre‐ and postsynaptic immunoreactive elements were clearly present in the host caudoputamen. Immunoreactive axons made synaptic contact with unlabeled dendrites; immunoreactive dendrites were postsynaptic to unlabeled axon terminals. The present results suggest that both host‐to‐graft and graft‐to‐host synapses are present in the

ISSN:0092-7317    

DOI:10.1002/cne.902400105

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

年代:1985

数据来源: WILEY

摘要:

AbstractHorseradish peroxidase was injected intra‐axonally into functionally identified cutaneous primary afferent fibers in the cat's spinal trigeminal nucleus in order to study the morphology of their central terminations. They were determined physiologically to be large, myelinated primary afferents including vibrissa, G1‐hair, and slowly adapting type I afferents, as well as small, myelinated primary afferents including D‐hair and A‐delta high‐threshold mechanoreceptive (HTM) afferents. The axons were stained for distances of 4–12 mm at the levels of the subnuclei interpolaris (Vi) and caudalis (Vc) of the spinal trigeminal nucleus. The collaterals of large, myelinated primary afferents formed terminal arbors in the outer part of the spinal trigeminal nucleus when they were rostral to or near the obex (rostral‐type collaterals), in lamina V when in the rostral part of Vc (caudalis‐type collaterals), and in lamina III/IV when in the caudal part of Vc (spinal dorsal horn‐type collaterals). There were no transitional forms between the rostral and caudalis types, but there was a transitional type which terminated in laminae III/IV and V between the caudalis and spinal dorsal horn types. Major morphological differences were not observed among the three functional types of large, myelinated primary afferents. The collaterals of D‐hair afferents showed the same types of collaterals as were seen in the large, myelinated primary afferents, except that terminal arbors of the spinal dorsal horn‐type collaterals were distributed in lamina IIb in addition to lamina III/IV. Collaterals of A‐delta HTM afferents formed extensive terminal arbors in the superficial part of Vi. In Vc they were distributed mainly in lamina I and few terminals existed in lamina IIa. The frequency of collaterals of A‐delta HTM afferents was less than that of the other types of afferents. The collaterals of A‐delta HTM afferents in Vi were distributed less frequently than those in Vc. The terminal arbors of A‐delta HTM afferents were less extensive than those of the other types of afferents. The average size of varicosities of A‐delta HTM afferents was smaller and that of vibrissa afferents was larger than that of the other types of afferents. This study demonstrated that there are large differences in the terminations of nociceptive and non‐nociceptive primary afferents and that Vi receives direct nociceptive input from facial skin. However, the sparse distribution of collaterals of HTM afferents in Vi suggests that the rostral trigeminal nucleus contributes partially to

ISSN:0092-7317    

DOI:10.1002/cne.902400106

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe distribution of leucine‐enkephalin, methionine‐enkephalin, neurotensin, somatostatin, substance P. oxytocin, vasopressin, and neurophysin II in cell bodies of sympathetic autonomic nuclei of the thoracolumbar (T‐L) spinal cord was studied immunohistochemically in cats after intrathecal administration of colchicine. Neurons containing only enkephalin‐, neurotensin‐, somatostatin‐, and substance P‐like immunoreactivity (ENK, NT, SS, SP, respectively) were found in the intermediolateral nucleus pars principalis (IMLp) and pars funicularis (IMLf), the nucleus intercalatus (IC), and the central autonomic area (CA). The size, shape, location, and numbers of the peptide‐positive neurons in the IMLp, IMLf, and IC suggested that they were sympathetic preganglionic neurons (SPN). This was confirmed by a combined retrograde tracing/immunohistochemical study showing that most of these neurons at the levels of the T‐L cord known to provide preganglionic fibers to the stellate ganglion were SPN. On the other hand, the functional identification of the neurons in the CA is uncertain as neurons were not observed which were both retrogradely labelled and contained ENK, NT, SS, or SP. Immunoreactive neurons in each area were counted in ten sections from each segment from C8 to L4. In the IMLp, the SPN with ENK were greatest in number (up to 25) in segments T4–T7 and L2–L3. The maximum number of SPN containing NT was found in segments T4–T7 (45 neurons). Of the four peptides, neurons containing SS were found in the greatest number (up to 48 in segments T2–T6); neurons containing SP were found in the smallest number (15 or fewer per segment). Few SPN containing each of the four peptides were found in the IC; CA neurons with ENK and NT were also few in number. A comparison of the numbers of immunoreactive neurons in the IML with earlier estimates for the total numbers of SPN in the IML at each level showed that the proportions of IML neurons containing each of the four peptides were fairly consistent throughout the T‐L cord, with some exceptions. These results suggest that the innervation of visceral organs is not obviously peptide‐specific, although some organs may be innervated by a greater proportion of SPN containing one of these peptides. Finally, the presence of ENK, NT, SS, and SP in SPN suggests that these four peptides act as neurotransmitters in preganglionic pa

ISSN:0092-7317    

DOI:10.1002/cne.902400107

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe distribution of leucine‐enkephalin, methionine enkephalin, neurotensin, somatostatin, substance P, oxytocin, vasopressin, neurophysin II, and serotonin in nerve terminals and fibers of sympathetic autonomic areas of the thoracolumbar (T‐L) spinal cord was studied immunohistochemically in cats. Densities of these immunoreactive terminals and fibers were estimated in the intermediolateral nucleus pars principalis (IMLp) and pars funicularis (IMLf), the nucleus intercalatus (IC), and the central autonomic area (CA). Results for leucine‐ and methionine‐enkephalin‐like immunoreactivity (ENK) were similar and immunoreactivity for vasopressin was not observed.The greatest numbers of terminals and fibers in the IMLp region contained ENK, neurotensin‐(NT), and serotonin‐like immunoreactivity (5HT); terminals and fibers containing substance P‐(SP) and neurophysin II‐like immunoreactivity (NP2) were intermediate in number, and those containing somatostatin‐(SS) and oxytocin‐like immunoreactivity (OXY) were generally sparse. In the IC and CA, terminals and fibers containing ENK and NT were dense, those containing SP were moderate, and those containing OXY, NP2, and 5HT were sparsely represented. In the IMLp, where the largest proportion of sympathetic preganglionic neurons (SPN) is found, the greatest concentration of terminals and fibers containing ENK was found in segments T1–T8; for NT these segments were T1–T5 and T11–L1, for SP–C8–T2 and T11–L1, for NP2–T4–T7 and L2 to L3, and for 5HT–T1–T5. Terminals and fibers containing SS and OXY were present in segments C8–T10 and segments C8, T2–T8, T13, and L2 to L3, respectively. These results indicate that while ENK, NT, SP, NP2, and 5HT fibers and terminals are widely distributed throughout the T‐L cord, they may influence to a greater degree the SPN in segments where they are present in greater numbers. As SS and OXY were not found at all levels of the I

ISSN:0092-7317    

DOI:10.1002/cne.902400108

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

年代:1985

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902400101

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

年代:1985

数据来源: WILEY