Showing papers by "Lars Olson published in 1982"

Prenatal ontogeny of neurons with enkephalin-like immunoreactivity in the rat central nervous system: an immunohistochemical mapping investigation.

Abstract: Immunohistochemical techniques were used to describe the presence of endogenous levels of enkephalin-like immunoreactivity (ELI) in the developing central nervous system of the rat up until birth. The appearance and prenatal ontogeny of nerve cell bodies, nerve fiber pathways and varicose terminal plexuses expressing ELI were thus mapped using the indirect fluorescence immunohistochemical technique and fluorescein- and rhodamine-conjugated second antisera. ELI was first observed in beaded fibers along the midline from ventral pons to cervical spinal cord by prenatal day 15. Fluorescence could not be observed in the brains of 14 day old fetuses, although the adrenal medulla did show ELI at this stage. ELI-positive cell bodies at prenatal day 18 were found in most areas in which they have previously been described in adult rats. Many of the cells observed at prenatal day 18 were, however, not seen in untreated full term fetuses with the techniques used here. ELI-positive fibers and terminal fields begin to approach adult distributions at prenatal day 21--22. Several ELI-positive axon pathways which have not been previously reported from adult or developing brain, such as e.g. pathways in medial neocortex, in fasciculus retroflexus, in tractus mammillothalamicus, between ventral hypothalamus and globus pallidus and between ventromedial pons and the locus coeruleus area, are described. Semischematic maps are presented which outline all ELI-positive material as seen in sagittal projections of the central nervous system of 15 day, 18 day and full term fetuses. Maps of representative transverse sections of the full term brain are also included.

Differential ethanol sensitivity of intraocular cerebellar grafts in long-sleep and short-sleep mice.

Abstract: The relative importance of extrinsic and intrinsic factors for the differential sensitivity of Purkinje neurons in long-sleep (LS) and short-sleep (SS) lines of mice was investigated using cerebellar grafts to the anterior chamber of the eye. Cerebellar anlagen from fetal LS and SS donors survive and mature in oculo when grafted within and across lines. Mature cerebellar transplants from all four groups contained Purkinje cells that show sustained spontaneous discharge; excitation and inhibition are readily evoked by electrical stimulation of the surface of the graft. Superfusion of ethanol into the anterior chamber depresses Purkinje cell discharge, but neurons from LS donors are approximately 1 order of magnitude more sensitive than SS neurons; this differential sensitivity is unaltered by the host recipient line used. These data strongly suggest that the differential sensitivity of Purkinje cells to ethanol in the LS and SS mouse lines is an intrinsic property of the cerebellum.

Cellular and subcellular localization of protein I in the peripheral nervous system.

Abstract: The cellular and subcellular distribution of protein I, a major brain phosphoprotein, has been studied in the peripheral nervous system. The levels of protein I in various peripheral nerves and innervated peripheral tissues were determined by radioimmunoassay and radioimmunolabeling of polyacrylamide gels. The results indicated tha protein I is present throughout the peripheral nervous system. Denervation studies of adrenal medulla and iris suggested that the protein I contained in peripheral tissues is localized to the neuronal elements innervating those tissues. Protein I was found to be enriched in neurotransmitter vesicle fractions of peripheral nervous tissue. Moreover, protein I appeared to be transported from cell bodies to axons terminals at least partly in association with neurotransmitter vesicles.

Anatomy of the isolated area dentata grown in the rat anterior eye chamber.

Abstract: We used the intraocular transplantation technique to test the developmental potential of isolated, fetal area dentata, and to help define the determinants of such critical aspects of brain development as cell arrangements, dendritic arborization, axon growth, synaptogenesis, and connectional specificity. Fetal hippocampal formations were removed from embryos of 19 to 20 days of embryonic age. A region, termed area dentata, was dissected from the hippocampal formation. This region included the anlage of the dentate gyrus, the hilus, and the medial regio inferior. Areae dentatae were transplanted into the anterior eye chamber of isogenic, adult rats. The growth and vascularization of area dentata transplants were monitored over the first 2 months in oculo. From 2 to 7 months after transplantation host animals were killed and the area dentata transplants were examined with a variety of histological techniques. The cytoarchitectonics of a great majority of the transplants were highly reminiscent of area dentata in situ. A typical morphogenetic outcome included tightly packed, continuous, C-shaped sheets of granule cells with mossy fibers which made contact with the proximal dendrites of a segregated group of dispersed hilar cells and a loosely packed layer of pyramidal cells. The axons of pyramidal and hilar cells, in turn, provided the major innervation of the granule cell dendrites. The granule cell dendritic spine density was nearly normal, and synapses were common in the granule cell neuropil. Very little innervation of the transplant was found to originate from the axons of the ciliary or trigeminal ganglia which innervate the host iris and enter the transplant. Sympathetic fibers from the host iris innervate the transplant in a reproducible and organotypic fashion although the degree of innervation is less than the in situ noradrenergic innervation of area dentata. Few Timm-positive fibers of the transplant were found to leave the transplant and enter the host iris. Area dentata transplants had several features which were different from their in situ counterparts. These differences included less expansive granule cell dendrites, extensive presence of fibrous astrocytes, pyramidal cells with reduced kainic acid sensitivity, hypervascularized neuropil, and transformation of peripheral adrenergic fiber morphology to one of central characteristics. Thus, pieces of isolated area dentata display a great self-developing capacity, in terms of cellular and afferent organization, both of which follow “rules” present in situ. A powerful capacity for intrinsic and appropriate innervation of area dentata is apparent in the face of a total lack of normal extrinsic afferents and an availability of extrinsic but inappropriate sources of innervation. This initial description of isolated area dentata organization in oculo is meant to lay the groundwork for experimental investigations into the regulatory mechanisms governing morphogenesis and afferent organization.

Intraocular development and adrenergic innervation of cortical and subcortical brain areas: influence of thyroid hormone deficiency.

Abstract: Various immature brain regions have been isolated by grafting to the anterior chamber of the eye of adult recipients. The role of thyroid hormones for the growth of these isolated brain areas as well