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L Puelles

Publications and source records attributed to L Puelles.

12 recordsLinked to original sources
PubMed1992

Distribution of neuropeptide Y-like immunoreactivity in the brain of the lizard Gallotia galloti.

The distribution of neuropeptide Y (NPY)-like immunoreactivity was studied in the brain of the lizard Gallotia galloti, in order to gain insight into the comparative topography of this peptide. Antisera against both NPY and its C-terminal flanking peptide (C-PON) were used, demonstrating a general coexistence of both peptides, as described in other vertebrates. Most NPY-like immunoreactive (NPY-LI) cell bodies were observed in the telencephalon, specifically in various olfactory structures, all cortices, septum, basal ganglia (except for the globus pallidus), the nucleus of the diagonal band of Broca, the amygdaloid complex, and the bed nucleus of the anterior commissure. NPY-LI cells were also seen in the preoptic and hypothalamic regions and the dorsal thalamus (mainly in the perirotundal belt), as well as in the mesencephalic tegmentum (in the ventral tegmental area, the substantia nigra, and the retrorubral area). NPY-LI fibers and terminals were widely distributed in the brain. All visual and auditory neuropiles were densely innervated. Specially dense plexuses were seen in the nucleus accumbens, the ventral pallidum, the suprachiasmatic and ventromedial hypothalamic nuclei, the nucleus medialis thalami, the left habenula, and the central nucleus of the torus semicircularis. Our analysis shows that the distribution of NPY-like immunoreactivity in the forebrain of Gallotia largely resembles that of other vertebrates, whereas differences are mainly observed in the brainstem. The widespread distribution of NPY in the lizard brain suggests several modulatory functional roles, either in local-circuit systems of the forebrain, or in various limbic, neuroendocrine, and sensory pathways.

Animals↗
PubMed1992

Tangential neuronal migration in the avian tectum: cell type identification and mapping of regional differences with quail/chick homotopic transplants.

This paper is a sequel to a previous report, using quail/chick chimeras with partial tectal transplants, in which a tangential invasion of host (chick) tectal territories by cells originating in the quail graft was demonstrated. The cells displaying this secondary tangential migration appeared restricted to two strata (stratum griseum centrale (SGC) and stratum griseum et fibrosum superficiale (SGFS)). Here we describe the morphology of the tangentially displaced neurons, as well as their overall distribution in the host tectal lobe, by means of an antibody that specifically recognizes quail cells, staining them in a Golgi-like manner. Neurons that migrated into the SGC are identified as multipolar projection neurons, typical of this stratum. The majority of cells that migrated into the SGFS correspond to horizontal neurons, as was also corroborated by observations in Golgi-impregnated material. These horizontal cells are concentrated in laminae b, d and f, where their processes form well delimited axonal plexuses. In confirmation of previous results, SGC neurons have a limited range of migration, whereas SGFS cells translocate across much longer distances. In reconstructions of appropriate cases, a remarkable polarity was noted. Significant invasion of chick tectum by quail cells mostly occurred in the rostral half of the host tectum. The long-range migration of superficial horizontal cells frequently reached, but did not cross, the rostral tectal boundary. Conversely, tangential migration in the caudal half of the host tectum was scarce and coincided with a typical arrangement of quail-derived radial columns interdigited with chick-derived columns. These findings are discussed in relation to existing data on immature neuronal populations, molecular marker distribution and polarity of the avian optic tectum.

Animals↗
PubMed1992

Prenatal development of calbindin immunoreactivity in the dorsal thalamus of the rat.

The distribution of calbindin immunoreactivity was studied in the developing rat dorsal thalamus at embryonic days 14, 16, 18 and 20. At early stages (days 14-16), calbindin is expressed throughout the dorsal thalamic cell mass. Most intense labeling occurs in cells adjacent to the ventricular surface, in a spatial gradient reflecting the well-known outside-in generation pattern. Between days 16 and 20, calbindin-positive periventricular cells are redistributed in the dorsal thalamus according to two different patterns. They first become oriented tangentially within the periventricular layer, and diminish in number at the central locus where midline thalamic fusion occurs at 18 days. Periventricular calbindin immunoreactivity becomes restricted to a ring of late-born cells surrounding the gray commissure. Recognizable portions of this ring-shaped primordium will mature forming n.paratenialis, n.reuniens, n.paraventricularis, and n.subparafascicularis magnocellularis. Simultaneously, a massive contingent of radially-oriented, fusiform, calbindin-positive young neurons extends from the periventricular ring-shaped aggregate to the lateral brain surface at the caudoventral pole of the dorsal thalamus at embryonic days 17/18. These cells surround the primordium of the medial geniculate body, participating in the constitution of its marginal zone, and invade the lateral posterior nucleus, accumulating within its caudomedial part. Other portions of this stream form the parvocellular subparafascicular nucleus and the peripeduncular nucleus. The observed patterns of calbindin expression suggest that dorsal thalamic postmitotic neurons transiently express the marker during initial phases of axogenesis, whereas a specific, late-born population expresses calbindin continuously into adulthood. This late subpopulation displays migratory behavior, and finally subdivides into several nuclei of the mature midline, superficial and posterior thalamus.

Animals↗
PubMed1992

In vitro HRP-labeling of the fasciculus retroflexus in the lizard Gallotia galloti.

In order to test the usefulness of the in vitro HRP-labeling technique in the brains of small lizards, the fasciculus retroflexus was labeled in isolated brains of young specimens of the lizard Gallotia galloti by means of HRP applied with the tip of a micropipette located approximately midway along the descending course of the tract. Cells in the medial and lateral habenular nuclei were labeled retrogradely. Anterograde transport showed the course of the fasciculus retroflexus, first dorsoventrally into the paramedian prerubral tegmentum and then longitudinally into the isthmic nucleus interpeduncularis. Some fibers spread dorsally into the mesencephalic and isthmic tegmental fields. A substantial bundle continues caudally into nucleus raphe parvocellularis. Other fibers diverge rostral-wards from the point of inflexion of the fasciculus, coursing longitudinally in the medial forebrain bundle into the basal telencephalon. Some fibers course rostrally from the nucleus habenularis lateralis in the stria medullaris and could be followed to the dorsal septum.

Animals↗
PubMed1992

Afferent connections of the habenular complex in the lizard Gallotia galloti.

Afferents to the habenular complex were studied by means of in vitro horseradish peroxidase retrograde labeling and anterograde control experiments in the lizard Gallotia galloti. The medial habenular nucleus was found to receive abundant afferent fibers from the nucleus of the posterior pallial commissure and the nucleus septalis impar. More restricted input comes from the nucleus eminentiae thalami and the nucleus of the stria medullaris. The lateral habenular nucleus is innervated by various fiber groups originating from the bed nucleus of the anterior commissure, the diagonal band nucleus, the lateral preoptic area, the anterior entopeduncular nucleus, the lateral hypothalamic and mammillary areas, the nucleus of the stria medullaris, the area tegmentalis ventralis and a scattered neuronal subpopulation in the large-celled dorsolateral nucleus of the dorsal thalamus. Habenulopetal fibers generally follow the stria medullaris, but hypothalamic, entopeduncular and dorsal thalamic afferents course through the dorsal peduncle of the lateral forebrain bundle in a transthalamic route. Mesencephalic ventral tegmental afferents ascend through the tractus retroflexus.

Afferent Pathways↗
PubMed1992

The pretectal complex of the rabbit: distribution of acetylcholinesterase and reduced nicotinamide adenine dinucleotide diaphorase activities.

The chemoarchitecture of the pretectal complex of the rabbit was examined in sections stained by acetylcholinesterase (AChE) and reduced nicotinamide adenine dinucleotide (NADH) diaphorase in the coronal, horizontal and sagittal plane. Twelve different subdivisions can be identified in the rabbit pretectum on the basis of the distribution of both histochemical markers. According to the standard terminology, the pretectal complex of the rabbit consists of: the nucleus of the optic tract; the anterior, posterior, olivary and medial pretectal nuclei; the nucleus of the posterior commissure; the periventricular subcommissural gray; the suprageniculate and internal suprageniculate nuclei, and the dorsal, lateral and medial terminal nuclei of the accessory optic system. The combined use of several sectioning planes and the histochemical mapping of AChE and NADH diaphorase have been of value in resolving the structural limits within transitional regions of the pretectum.

Acetylcholinesterase↗
PubMed1992

Reduced junctional permeability at interrhombomeric boundaries.

Intercellular communication is considered to have a role during pattern specification processes in early embryonic development. This report analyzes the changing gap junctional communication properties of chick neuroepithelial cells depending on their position relative to the segmental partitions of the rhombencephalon. Intercellular electrical coupling and dye transfer were studied with microelectrode techniques. Neuroepithelial cells were electrically coupled irrespective of their location relative to interneuromeric boundaries. Iontophoretic injection of biocytin or Lucifer Yellow into single cells inside the rhombomeres was followed by transjunctional diffusion to the surrounding cells. In contrast, dye transfer was strictly limited when the diffusion zone contacted the cells forming the interneuromeric limits. Label injected into the boundary cells did not spread to other cells at all. Avian interrhombomeric boundaries are thus sites of reduced junctional permeability during early morphogenesis.

Animals↗
PubMed1990

Acetylcholinesterase-histochemical differential staining of subdivisions within the nucleus rotundus in the chick.

Histochemical mapping of AChE activity in the chick diencephalon shows differential staining of several subregions within the nucleus rotundus. The topography and extent of these subdivisions were studied in transverse, horizontal and sagittal sections. A correlation with rotundic hodologic subdivisions reported in the literature is feasible, whereas several other chemoarchitectonic or functional markers show a homogeneous distribution throughout the n. rotundus. Moreover, cholinergic markers do not detect cholinergic afferents within the rotundic neuropile. Late embryonic appearance of the AChE heterogeneity suggests a modulation of neuropile AChE levels subsequent to synaptogenetic adjustment of differential hodology.

Acetylcholinesterase↗
PubMed1978

A Golgi-study of oculomotor neuroblasts migrating across the midline in chick embryos.

The Golgi-Stensaas impregnation technique was employed at appropriate stages of development to study the morphology of the oculomotor neuroblasts as these migrate across the midline. Data reported in previous publications were confirmed, such as the timing of the migration (occurring between the 4th and the 9th days of inoculation), the fact that the migrating cells carry their axons across the midline as trailing processes, and the absence of pre-existing fibrillar structures able to provide contact guidance for this migration. The most striking new fact discovered is that the leading processes of the oculomotor neuroblasts are often branched, and that all these branches are uniformly oriented towards the midline. This seems to indicate the existence of a non-random growth process. It is argued in the discussed that this can be explained through the presence of an orienting neurotropic influence. This one could have its source in certain non-oculomotor neuroblasts which were detected within the midline ventricular zone. On morphological grounds, this group of cells may be tentatively identified as the avian counterpart of the midventral mesencephalic proliferation described in several mammals. This proliferative zone is known to contain dopamine at early stages of development. A hypothetic casual mechanism of the oculomotor migration is therefore advanced, wherein dopamine, diffusing out of the non-oculomotor midline neuroblasts, induces at short range oriented outgrowth of oculomotor leading processes across the midline.

Animals↗
PubMed1977

Do oculomotor neuroblasts migrate across the midline in the retal rat brain?

Toluidine blue-stained semithin sections and Cajal-Castro preparations are used to study in rat fetuses whether oculomotor neuroblasts migrate across the midline at a certain period of development. In confirmation of previous studies, a group of oculomotor neuroblasts was detected which first grow cytoplasmic processes into the mesencephalic midline, and afterwards translocate their somata towards the midline, between the 12th and the 15th days of gestation. At this moment a midline mass of neuroblasts characterizes the meeting at this landmark of both left and right migrating neuroblastic groups. No crossing oculomotor axons yet are demonstrable with reduced silver techniques. In further stages of development the neuroblasts continue their migration until they arrive at the contralateral nucleus at the 16th and 17th day of gestation. At the midline the mass of neuroblasts disappears gradually and crossed oculomotor axons become visible. The electron microscope was then used to study ultrastructurally the migrating motoneurons. It was discovered that no preexisting structure guides their movement by contact. Their leading processes show no filopodial activity, and contain abundant microtubules and thick bundles of neurofilaments in eccentric position. The neuroblasts carry their axon across the midline as a trailing process.

Animals↗