Summary
Electron-dense tracers were used to study the permeability of the blood—brain interface in a cephalopod mollusc, the cuttlefishSepia officinalis. Gel filtration established that horseradish peroxidase is a suitable tracer forin vivo injection, but microperoxidase is not, being subject to binding by plasma proteins. Perfusion-fixed brain vertical and optic lobes showed no endogenous peroxidatic activity. Horseradish peroxidase was injected intravenously, and allowed to circulate for 10–35 min before tissue fixation by immersion or perfusion. Horseradish peroxidase reaction product was undetectable in the bulk of the brain parenchyma. In microvessels, venous vessels and at the brain surface, horseradish peroxidase penetrated the layers of endothelial and pericyte cells, being stopped by the layer of perivascular glia. In arterial vessels, tracer restriction occurred at the level of the pericytes. In the region of tracer blockade, a gradient of tracer could be traced in the intercellular cleft, from high at the luminal end to undetectable at the tissue end. The clefts of the restricting zone were generally wide (15–20 nm), with faint periodicities or linking structures spanning the cleft, and contained a fibrillar extracellular material. Perfusion of lanthanum chloride in saline for 15 min, followed by precipitation of lanthanum phosphate during fixation, resulted in lanthanum tracer distribution similar to that of horseradish peroxidase. Horseradish peroxidase was seen filling extracellular spaces within the neuropile when the blood—brain barrier was breached by a stab wound, indicating that the interstitum itself does not restrict tracer diffusion. It is concluded thatSepia has a blood—brain barrier tight to horseradish peroxidase and ionic lanthanum. The restricting junction is not a typicalzonula occludens or septate junction, but appears to reduce tracer penetration by a filtering mechanism within the extracellular cleft. The barrier is formed by perivascular glial cell processes in the microvessels and venous vessels, but by pericytes in arterial vessels. This organization suggests that a glial blood—brain barrier may be the primitive condition, and a barrier associated with vascular elements (endothelium/pericyte) a later development.
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References
Abbott, N. J. &Bundgaard, M. (1987) Microvessel surface area, density and dimensions in brain and muscle of the cephalopodSepia officinalis.Proceedings of the Royal Society B,230, 459–82.
Abbott, N. J., Bundgaard, M. &Cserr, H. F. (1981) Fine-structural evidence for a glial blood—brain barrier to protein in the cuttlefish,Sepia officinalis.Journal of Physiology 316, 52–53P.
Abbott, N. J., Bundgaard, M. &Cserr, H. F. (1986a) Comparative physiology of the blood—brain barrier. InThe Blood-Brain Barrier in Health and Disease (edited bySuckling, A. J., Rumsby, M. G. &Bradbury, M. W. B.) pp. 52–72. Chichester: Ellis Horwood.
Abbott, N. J., Lane, N. J. &Bundgaard, M. (1986b) The blood—brain interface in invertebrates.Annals of the New York Academy of Sciences 481, 20–41.
Abbott, N. J., Bundgaard, M., Lane, N. J. &Møllgård, K. (1988) Parallels between junctions in invertebrate brain and embryonic mammalian brain.Journal of Physiology 400, 72P.
Abbott, N. J., Lane, N. J. &Bundgaard, M. (1992) A fibre-matrix model for the restricting junction of the blood—brain barrier in a cephalopod mollusc: implications for capillary and epithelial permeability.Journal of Neurocytology 21, 304–311.
Arthur, F. E., Shivers, R. R. &Bowman, P. D. (1987) Astrocyte-mediated induction of tight junctions in brain capillary endothelium: an efficientin vitro model.Developmental Brain Research 36, 155–9.
Barber, V. C. &Graziadei, P. (1965) The fine structure of cephalopod blood vessels. I. Some smaller peripheral vessels.Zeitschrift für Zellforschung und mikroskopische Anatomie 66, 765–81.
Barber, V. C. &Graziadei, P. (1967) The fine structure of cephalopod blood vessels. II. The vessels of the nervous system.Zeitschrift für Zellforschung und mikroskopische Anatomie 77, 147–61.
Bouldin, T. W. &Krigman, M. R. (1975) Differential permeability of cerebral capillary and choroid plexus to lanthanum ion.Brain Research 99, 444–8.
Bradbury, M. W. B. (1979)The Concept of a Blood-Brain Barrier. Chichester: Wiley.
Brightman, M. W. &Reese, T. S. (1969) Junctions between intimately apposed cell membranes in the vertebrate brain.Journal of Cell Biology 40, 648–77.
Browning, J. (1979)Octopus microvasculature: permeability to ferritin and carbon.Tissue and Cell 11, 371–83.
Bundgaard, M. (1982) Ultrastructure of frog cerebral and pial microvessels and their permeability to lanthanum ions.Brain Research 241, 57–65.
Bundgaard, M. &Møller, M. (1981) Horseradish peroxidase and microperoxidase. Their purity and binding to serum proteins.Journal of Histochemistry and Cytochemistry 29, 331–6.
Bundgaard, M. &Abbott, N. J. (1992) Fine structure of the blood—brain interface in the cuttlefishSepia officinalis (Mollusca, Cephalopoda).Journal of Neurocytology 21, 260–275.
Davson, H., Welch, K. &Segal, M. B. (1987)The Physiology and Pathophysiology of the Cerebrospinal Fluid. Edinburgh: Churchill Livingstone.
Froesch, D. &Mangold, K. (1976) Uptake of ferritin by the cephalopod optic gland.Cell and Tissue Research 170, 549–51.
Graham, R. C. &Karnovsky, M. J. (1966) The early stages of absorption of injected horseradish peroxidase in the proximal tubules of mouse kidney; ultrastructural cytochemistry by a new technique.Journal of Histochemistry and Cytochemistry 14, 291–302.
Gray, E. G. (1969) Electron microscopy of the glio-vascular organization of the brain ofOctopus.Philosophical Transactions of the Royal Society B 255, 13–32.
Janzer, R. C. &Raff, M. C. (1987) Astrocytes induce blood—brain barrier properties in endothelial cells.Nature 325, 253–7.
Lane, N. J. &Abbott, N. J. (1992) Freeze-fracture evidence for a novel restricting junction at the blood—brain barrier of the cuttlefishSepia officinalis.Journal of Neurocytology 21, 295–303.
Reese, T. S. &Karnovsky, M. J. (1967) Fine structural localization of a blood—brain barrier to exogenous peroxidase.Journal of Cell Biology 34, 207–17.
Tao-Cheng, J.-H., Nagy, Z. &Brightman, M. W. (1987) Tight junctions of brain endotheliumin vitro are enhanced by astroglia.Journal of Neuroscience 7, 3293–9.
Wells, M. J. (1978)Octopus. Physiology and Behaviour of an Advanced Invertebrate. London: Chapman & Hall.
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Abbott, N.J., Bundgaard, M. Electron-dense tracer evidence for a blood—brain barrier in the cuttlefishSepia officinalis . J Neurocytol 21, 276–294 (1992). https://doi.org/10.1007/BF01224761
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DOI: https://doi.org/10.1007/BF01224761