A vertebrate-like blood--brain barrier, with intraganglionic blood channels and occluding junctions, in the scorpion
Abstract
India ink and ionic lanthanum injections have revealed that the central nervous system (CNS) of the scorpion possesses a highly vascularized cephalothoracic ganglionic mass. It, together with other abdominal ganglia which form a ventral nerve cord, are all ensheathed by an outer layer of modified glial, or perineurial, cells. These cells resemble those which line the blood channels permeating the CNS, in exhibiting both inverted gap and tight junctions. Although the latter show close or fused membrane appositions, lanthanum appears to penetrate past a number, but not all, of them. Freeze-fracturing reveals that these junctions are composed of E-face particles aligned into a network of rows, or ridges, which are frequently discontinuous, especially near the periphery of the perineurium. This produces a somewhat 'leaky' system but occlusion to tracers occurs ultimately, for in the CNS none can be found beyond the perineurium. The existence of this perineurial blood-brain barrier is also demonstrable electrophysiologically where cations such as Mg2+ are unable to penetrate beyond the perineurial layer although they can, it seems, leak in via the blood vascular system. Relative differences in tightness between the perineurium and t...Continue Reading
References
Lack of restriction at the blood-brain interface in Limulus despite atypical junctional arrangements
Citations
Related Concepts
Related Feeds
Blood Brain Barrier Regulation in Health & Disease
The blood brain barrier is essential in regulating the movement of molecules and substances in and out of the brain. Disruption to the blood brain barrier and changes in permeability allow pathogens and inflammatory molecules to cross the barrier and may play a part in the pathogenesis of neurodegenerative disorders. Here is the latest research in this field.
Blood Brain Barrier Chips
The blood brain barrier (BBB) is comprised of endothelial cells that regulate the influx and outflux of plasma concentrations. Lab-on-a-chip devices allow scientists to model diseases and mechanisms such as the passage of therapeutic antibodies across the BBB. Discover the latest research on BBB chips here.
Blood Brain Barrier
The blood brain barrier is a border that separates blood from cerebrospinal fluid. Discover the latest search on this highly selective semipermeable membrane here.