Search PubMed⌕ Search

Biomedical subjects

C Gall

Publications and source records attributed to C Gall.

At least 55 records · Page 3Linked to original sources
PubMed1985

Distribution of calpain I, an enzyme associated with degenerative activity, in rat brain.

The calcium-activated protease calpain I was localized in rat brain by immunocytochemistry. Calpain I-like immunoreactivity (CLI) was prominent in several structures in which degeneration is an ongoing feature, e.g. spinal motoneurons, olfactory nerve. Also noteworthy was the presence of CLI in regions susceptible to age-related pathologies, e.g. cerebellar Purkinje cells, substantia nigra and subiculum. This distribution suggests that calpain I may be involved with both normal and pathological neuronal degeneration.

Animals↗
PubMed1985

Distribution of cholecystokinin-like immunoreactivity in the rat main olfactory bulb.

The anatomical localization of cholecystokinin-like immunoreactivity (CCK-I) within the rat main olfactory bulb was analyzed by using the peroxidase-antiperoxidase immunocytochemical technique. Neurons or neuronal processes containing CCK-I were localized within all laminae of the olfactory bulb except the olfactory nerve fiber layer. A large population of CCK-I neurons, with morphology, size, and distribution corresponding to that of the middle and external tufted cells, was observed within a zone extending from the deep periglomerular region through the superficial one-half to one-third of the external plexiform layer. A smaller number of immunoreactive perikarya were found in the deep external plexiform layer, the glomerular layer, and rarely within the inner plexiform layer. These CCK-I neurons appeared to correspond to internal tufted cells, periglomerular cells, and deep short-axon cells, respectively. Dense CCK-I staining of fibers and terminals was present within the internal plexiform layer and, less densely, within the neuropil of the granule cell layer. In addition, terminal-like CCK-I was localized within layer 1A of the anterior olfactory nucleus, the olfactory tubercle, and the most rostral piriform cortex. This observation provides corroboration for the identification of the principal CCK-I neuron in the rat olfactory bulb as the centrally projecting middle tufted cell. The present results, demonstrating the localization of CCK-I to both local circuit and projection neurons of the olfactory bulb and to terminal-like puncta in the internal plexiform and granule cell layers, suggest that CCK may be significantly involved in olfactory processing at several levels.

Animals↗
PubMed1985

Gap junction structures. VII. Analysis of connexon images obtained with cationic and anionic negative stains.

Micrographs of isolated gap junction specimens, negatively stained with one molybdate, three tungstate and three uranyl stains, were recorded at low and high irradiation. Fourier-averaged images of the negatively stained gap junctions have been self-consistently scaled to identify conserved and variable features. Intrinsic features in the hexagonally averaged images have been distinguished from residual noise by statistical comparisons among similarly prepared specimens. The cationic uranyl stains can penetrate the axial connexon channel, whereas the anionic stains are largely excluded; these observations indicate that the channel is negatively charged. Variability in the extent of the axial stain penetration, and enhancement of this staining by radiation damage and heating may be accounted for by a leaky, labile channel gate. The peripheral stain concentrations marking the perimeter of the skewed, six-lobed connexon image and the stain-excluding region at the 3-fold axis of the lattice, which are seen only under conditions of low irradiation with both anionic and cationic stains, are identified as intrinsic features of the isolated gap junction structure. The stain concentrations located approximately 30 A from the connexon center appear to be symmetrically related on opposite sides of the junction by non-crystallographic 2-fold axes oriented approximately 8 degrees to the lattice axes at the plane of the gap. The radiation-sensitive hexagonal features seen in the negatively stained images may correspond to substructure on the cytoplasmic surfaces of the paired gap junction membranes.

Animals↗
PubMed1984

Supramammillary afferents to guinea pig hippocampus contain substance P-like immunoreactivity.

The origin of substance P immunoreactive (SPI) axons in guinea pig hippocampus was analyzed using immunocytochemical techniques combined with transections and retrograde transport of fluorescent dye. A unilateral depletion of hippocampal axonal SPI was observed following ipsilateral transection of rostral hippocampus and fibria suggesting that the vast majority of SPI axons in hippocampus are extrinsic afferents which enter the structure from the septal pole. The combined use of immunocytochemistry and fluorescent dye transport demonstrated the supramammillary region of the hypothalamus to be the only area where dye-labeled hippocampal afferent neurons also exhibited SPI. These data indicate that the supramammillary region is the principal source of SPI axons in guinea pig hippocampus and, most probably, in the hippocampus of other animals (squirrel, cat, monkey) sharing a similar pattern of axonal SPI.

Animals↗
PubMed1984

Ontogeny of dynorphin-like immunoreactivity in the hippocampal formation of the rat.

Light microscopic immunocytochemical techniques were used to analyze the ontogeny of dynorphin (A)-like immunoreactivity (DLI) in the hippocampal formation of the Sprague-Dawley rat. For comparison purposes, alternate sections of the same brains were processed for the localization of methionine enkephalin-like immunoreactivity (ELI). DLI was first detectable in CA3a stratum lucidum and the suprapyramidal hilus on postnatal day (P) 6. On P7, DLI was evenly present throughout the full extent of the mossy fiber system. From P8 to P19, DLI progressively increased in intensity and could be localized in the fine axons and spherical swellings. The mossy fiber system and occasional perikarya superficial to stratum granulosum were the only hippocampal elements that exhibited DLI. In corroboration with earlier results, stratum lucidum ELI was first detected within large spherical bouton-like swellings on P13. From these data it is concluded that DLI appears in morphologically immature mossy fibers soon after they reach their target fields. In contrast, enkephalin is first detected within morphologically elaborated mossy fiber boutons well after the establishment of functional synapses.

Animals↗
PubMed1984

The distribution of cholecystokinin-like immunoreactivity in the hippocampal formation of the guinea pig: localization in the mossy fibers.

Immunocytochemical techniques were used to localize cholecystokinin octapeptide (CCK-8)-like immunoreactivity in the hippocampal formation of the guinea pig. As in the rat, CCK immunoreactive perikarya are most dense in and around the stratum pyramidale, within the superficial cell layer of the subiculum, and within the polymorph zone of the hilus. Immunoreactive axons are observed within and loosely surrounding the stratum pyramidale, within the stratum lacunosum moleculare, and diffusely distributed across the subiculum. In contrast to the rat, the mossy fiber system also exhibited significant CCK immunoreactivity. The latter system has previously been demonstrated to contain enkephalin-like immunoreactivity in the guinea pig. The present results suggest, therefore, that the enkephalin-like and CCK-like substances either coexist within the mossy fiber boutons or are present within separate subpopulations of the mossy fibers.

Animals↗
PubMed1984

Distribution of enkephalin, substance P, tyrosine hydroxylase, and 5-hydroxytryptamine immunoreactivity in the septal region of the rat.

Immunocytochemical methods were used to define the distribution of enkephalin (ENK), substance P (SP), tyrosine hydroxylase (TH), and serotonin (5-hydroxytryptamine: 5HT) in the rat septum. A dense plexus of axons containing enkephalin-like immunoreactivity is found in the intermediate lateral septal nucleus. This is surrounded laterally by SP-containing cell bodies and axons and medially by ENK-containing cell bodies. Both SP- and ENK-immunoreactive axons form pericellular and peridendritic terminal arbors around lateral septal neurons. TH-positive axons are distributed throughout the septum and form dense pericellular terminal baskets around scattered neurons in the medial half of the intermediate lateral septal nucleus and in the extreme lateral septum. Very few SP and TH immunoreactive axons are present in the ENK immunoreactive plexus zone. 5HT-immunoreactive axons are most dense at the lateral edge of the ventral and intermediate lateral septal nuclei but form pericellular terminal arbors only in the dorsal lateral septal nucleus, in the septofimbrial nucleus, and in the dorsal cap of the medial septal nucleus. These results indicate that the dorsal and intermediate lateral septal nuclei include three histochemically distinct laminated subfields: (1) an ENK immunoreactive axonal plexus within the lateral aspect of the intermediate lateral septal nucleus, (2) a more medial region of scattered ENK immunoreactive perikarya and similarly scattered TH immunoreactive pericellular baskets, and (3) a dorsolateral zone occupied by SP neurons and 5HT-containing pericellular baskets. Thus, the data suggest that SP- and ENK-containing neuronal populations in the lateral septum receive different monoaminergic inputs. Further, the somewhat exclusive laminated pericellular termination of peptide- and catecholamine-containing axons in the lateral septum predicts very different functional and pharmacological properties among zones.

Animals↗
PubMed1984

The distribution of the commissural-associational afferents of the dentate gyrus after perforant path lesions in one-day-old rats.

Lesions were made in the entorhinal cortex of one-day-old rats and the distribution of the axons in the dentate gyrus molecular layer studied with the Holmes silver stain when the animals reached adulthood. The commissural-associational projections, normally restricted to the inner dendritic zones, spread evenly throughout the molecular layer ipsilateral to the lesion. This pattern of aberrant growth is markedly different from that which occurs after entorhinal lesions placed in 7-day-old rats. The results are discussed in terms of the factors that dictate the topography of developing afferents.

Afferent Pathways↗
PubMed1984

Ontogeny of enkephalin-like immunoreactivity in the rat hippocampus.

The postnatal development of leucine5-enkephalin-like immunoreactivity within the hippocampal formation of the rat has been analyzed using immunocytochemical techniques. From the day of birth to postnatal day three, no intrinsic hippocampal elements exhibit immunoreactivity although labeled axons are found within the fimbria, within the alveus, and in the vicinity of the angular bundle. On postnatal day 4, a few immunoreactive hippocampal neurons can be seen in stratum radiatum of the region CA3 and by postnatal day 8, within the hilus, strata pyramidale and oriens of regio superior, and the subiculum. There is a dramatic increase in the incidence of immunoreactive perikarya between postnatal days 8 and 10 in all fields as well as the appearance of labeled neurons in CA1 stratum pyramidale and stratum granulosum of the dentate gyrus. Two days after the first appearance of immunoreactive perikarya, intensely immunoreactive neurons, labeled much more extensively than is ever seen in the adult, are encountered in each subfield of the hippocampus. The spatio-temporal order in both the emergence of perikaryal immunoreactivity and the transient appearance of intensely immunoreactive neurons follows that of neurogenesis, with immunoreactivity developing 12-14 days after the peak period of last cell division for a given hippocampal region. The incidence of immunoreactive perikarya in the dentate gyrus was quantified in rat pups ranging from postnatal days 8 to 19. The appearance of labeled neurons followed the spatio-temporal gradients that have been described for neurogenesis in this region as well. Immunoreactive perikarya emerged in the suprapyramidal stratum granulosum prior to their emergence in the infrapyramidal zone and in the temporal pole of the dentate earlier than in the mid-dorsoventral dentate. The lateral perforant path and mossy fiber axons, seen to exhibit enkephalin-like immunoreactivity in the adult hippocampal formation, differ in their relative maturity at the age immunoreactivity first appears. Immunoreactivity appears as early as postnatal day 4 in the lateral perforant path, an age at which these axons are just growing into their target field while it is not found within the mossy fibers until after postnatal day 10, an age at which mossy fiber bouton elaboration is well advanced and physiologically competent mossy fiber synapses with the regio inferior pyramidal cells have been established. The latter observation indicates that enkephalin is not necessary for synaptic transmission at the mossy fiber synapse.

Aging↗
PubMed1983

Denervation-induced decrease in mitochondrial calcium transport in rat hippocampus.

Calcium accumulation by mitochondria and the activity and in vitro phosphorylation of pyruvate dehydrogenase were measured in control and partially denervated hippocampus. Calcium uptake was measured with a calcium-sensitive electrode and 45Ca2+ accumulation; both methods indicated that lesions of the entorhinal cortex produced a sizable reduction of calcium transport when mitochondria were fueled with pyruvate while much smaller changes were observed using succinate or ATP as energy sources. The decrease in calcium transport was evident by 24 hr after the lesion and was still present 6 months later. Synaptic and nonsynaptic mitochondria were similarly affected by the lesions. The activity and in vitro phosphorylation of pyruvate dehydrogenase were also significantly reduced following lesions of the entorhinal cortex, suggesting that denervation altered the endogenous state of phosphorylation of the mitochondrial enzyme. Commissural lesions but not septal lesions also resulted in a decrease in mitochondrial calcium transport when mitochondria were fueled with pyruvate. These findings suggest that denervation disturbs mitochondrial regulation of free calcium via an action on enzymes which regulate pyruvate dehydrogenase phosphorylation and activity. The potential relationship of this effect to degenerative changes associated with deafferentation and certain disease states is discussed.

Adenosine Triphosphate↗
PubMed1982

Distribution of enkephalin-like immunoreactivity in the rat main olfactory bulb.

Enkephalin-like immunoreactivity was localized within the main olfactory bulb of the rat using immunohistochemical techniques. These studies utilized well characterized antisera directed to either leu5- or met5-enkephalin. Specificity was established by absorption of the antisera with either 10 microM synthetic leu5- or met5-enkephalin. Specific enkephalin-like immunoreactivity was observed within several different cell populations including (1) periglomerular cells, (2) granule cells and their processes within the external plexiform layer and (3) occasional short-axon (horizontal) cells within the granule and external plexiform layers. The granule cell layer contained the greatest number of immunoreactive cells. Only a limited number of immunoreactive cells were found in both the periglomerular and granule cell layers, suggesting the enkephalin-containing neurons represent a sub-population within each layer. The absence of immunoreactive processes in the periventribular white matter, as well as the morphologies of immunoreactive bulbar neurons, indicates that enkephalin is found exclusively within intrinsic olfactory bulb neurons.

Animals↗
PubMed1981

Localization of enkephalin-like immunoreactivity to identified axonal and neuronal populations of the rat hippocampus.

The distribution of enkephalin-like immunoreactivity in the hippocampal formation of the rat was analyzed. Two specific projection systems are described. The first emerges from the hilus of the dentate gyrus and appears to terminate with notably large boutons on the proximal apical and, to a lesser extent, basal dendrites of hippocampal regio inferior pyramidal cells. This projection corresponds in source, position, and character to the hippocampal mossy fiber system. The second axonal population enters the temporal hippocampal formation from the medial wall of the subicular complex and follows the hippocampal fissure to occupy stratum lacunosum-moleculare of the hippocampus proper and the distal third of the dentate gyrus molecular layer; this pattern corresponds to the distribution of afferent input from the lateral entorhinal cortex and/or perirhinal area. Lesions of the hilus or retrohippocampal area caused a selective depletion of immunoreactivity in the mossy fiber fields and molecular layers of the dentate gyrus, respectively. Enkephalin-like immunoreactivity was found within the somata of three types of hippocampal neurons: 1) granule cells of the dentate gyrus, 2) occasional pyramidal shaped cells of field CA1 stratum pyramidale, and 3) varied scattered interneurons. Of this last group, two types of interneurons were consistently seen. The first occupy the border between stratum radiatum and stratum lacunosum-moleculare and extend processes at right angles to the long axis of the pyramidal cell dentrites, whereas the second lie within stratum radiatum of field CA1 and extend processes in alignment with the long axis of the pyramidal cell dendrites. Cells containing enkephalin-like immunoreactivity were also observed in the subiculum and retrohippocampal region, most notably including layers II and III of the lateral entorhinal cortex-perirhinal area--the probable source of extrinsic immunoreactive input to the hippocampal formation. Intraventricular colchicine treatment intensified the immunoreactive staining of some hippocampal neurons but did not reveal any cell types not seen to be labeled in untreated rats.

Animals↗
PubMed1980

Accelerated rates of synaptogenesis by "sprouting" afferents in the immature hippocampal formation.

Light and electron microscopic methods were used to study the rate with which undamaged afferents sprout into and form synapses within denervated dendritic zones in the immature rat brain. The middle and outer molecular layers of the dentate gyrus were deafferented by ablation of the ipsilateral entorhinal cortex in 14-day-old rats, and the extension of the commissural projections, which are normally restricted to the inner molecular layer, into the denervated territory was studied by light microscopic autoradiographic tracing methods. Collateral growth was noted as early as 13 hours after the lesion and was found to reach throughout the middle and outer molecular layers by 48 hours postlesion. Quantitative analyses (grain counts) revealed that the addition of commissural fibers and terminals to the denervated zones proceeded extremely rapidly up to 72 hours after the removal of the entorhinal cortex, but slowed markedly thereafter. Electron microscopic procedures were used to assess the rate at which synapses formed during this period and yielded the following information: 1) The density of intact synapses fell to below 20% of normal values within 20 hours of the lesion, 2) reinnervation began before 30 hours postlesion, and 3) the rate at which synapses were added to deafferented middle molecular layer was much more rapid from 20-96 hours postlesion than is observed in this zone during normal development. Furthermore, the sprouting of the inner molecular layer afferents into the middle molecular layer did not retard the pace of synaptogenesis in their normal target region. These results suggest that intrinsic limitations in the capacity of axons and dendrites are not responsible for determining the rate of synaptogenesis in the developing hippocampus. It is proposed instead that existing synapses (or terminals and spines) tend to suppress the formation of new contacts such that the local density of connections regulates the speed with which further innervation occurs.

Animals↗
PubMed1979

The effect of collateral sprouting on the density of innervation of normal target sites: implications for theories on the regulation of the size of developing synaptic domains.

The 'commissural' innervation of the dentate gyrus molecular layer has been analyzed in normal adult rats and in those in which the ipsilateral entorhinal cortex had been removed by aspiration at 14 days post-natal. This ablation severely deafferents the distal two-thirds of the molecular layer and induces 'sprouting' by the commissural afferents which are normally restricted to the more proximal dendritic zone. It was the objective of the present study to employ quantitative electron microscopy to determine (1) the extent of synaptic recovery in the deafferented field; (2) the magnitude of the contribution by the commissural fibers to the reinnervation of the deafferented field; and (3) if sprouting by the commissural projections causes a reduction in the density of the terminal field they generate in their normal target region. The synaptic density of the neonatally deafferented middle molecular layer was found to have returned to near control levels by adulthood. Degeneration studies performed in the adult revealed that commissural endings were located in equivalent numbers in the inner and middle molecular layers of rats in which the entorhinal cortex had been removed at 14 days post-natal; in normal rats (i.e. no neonatal surgery) the commissural terminals were found only in the inner molecular layer. Furthermore, and most importantly, the density of commissural terminals in the inner molecular layer was virtually identical in the 'sprouted' and control rats. Thus the tremendous areal expansion of the commissural terminal field which occurs after early deafferentation of the distal parts of the granule cell dendrites was not accompanied by any loss of input to the normal target of this afferent. Therefore, sprouting in this system represents an exaggeration of normal growth rather than a redistribution of a fixed population of endings. The relevance of these findings to theories concerned with the regulation of axonal growth and terminal proliferation during development is discussed.

Aging↗
PubMed1979

Proliferative and migratory activity of glial cells in the partially deafferented hippocampus.

The proliferative response of the glial cell population of the adult rat hippocampus deafferented by unilateral lesion of the entorhinal cortex was studied using 3H-thymidine autoradiography. Two experimental paradigms were used, involving: (1) intraventricular 3H-thymidine injection at a number of post-lesion intervals with sacrifice six hours later and (2) intraventricular injection at 30 hours post-lesion with sacrifice at 6, 96, or 192 hours later. The first increase in the number of labeled glial cells was obtained at 20 hours post-lesion and was confined to areas of degenerating axons. By 30 hours a large and uniformly dense proliferative response was observed throughout the ipsilateral, and medial aspects of the contralateral, hippocampus encompassing both deafferented and intact regions. Cell division continued through 50 and 65 hours post-lesion particularly in directly deafferented regions, but diminished to control levels by 80 hours. Although oligodendroglia and astrocyte-like cells were sometimes found to have incorporated the label the most common proliferative element within the hippocampus corresponded to previous light microscopic descriptions of "microglial" cells. The experiments using thymidine injection given at the peak proliferative period followed by survival periods of varying lengths indicated that a progressive redistribution of labeled nuclei occurred resulting in an accumulation of labeled cells in the zones of deafferentation. Multiple division of cells within these areas as well as the migration of nuclei from non-deafferented regions was found to contribute to this effect. The possible involvement of glial proliferation with other morphological effects of deafferentation, including the sprouting response of intact afferents, is discussed.

Animals↗