Editing Blood–brain barrier (section)

==History==
A 1898 study observed that low-concentration "[[bile salt]]s" failed to affect behavior when injected into the blood of animals. Thus, in theory, the salts failed to enter the brain.<ref>{{cite journal |last1=Biedl |first1=A |last2=Kraus |first2=R |date=1898 |title=Über eine bisher unbekannte toxische Wirkung der Gallensäuren auf das Zentralnervensystem |trans-title=A previously unknown toxic effect of bile acids on the central nervous system |journal=[[Zentralblatt Inn Med]] |volume=19 |pages=1185–1200}} Google Scholar: [https://scholar.google.com/scholar?cluster=4353654721035571173 4353654721035571173]</ref>

Two years later, [[Max Lewandowsky]] may have been the first to coin the term "blood–brain barrier" in 1900, referring to the hypothesized semipermeable membrane.<ref name=":0">{{cite web |title=History of Blood-Brain Barrier |url=https://davislab.med.arizona.edu/history-blood-brain-barrier |access-date=2023-11-02 |website=Davis Lab |publisher=The University of Arizona}}</ref> There is some debate over the creation of the term ''blood–brain barrier'' as it is often attributed to Lewandowsky, but it does not appear in his papers. The creator of the term may have been [[Lina Stern]].<ref>{{cite journal |last1=Saunders |first1=Norman R. |last2=Dreifuss |first2=Jean-Jacques |last3=Dziegielewska |first3=Katarzyna M. |last4=Johansson |first4=Pia A. |last5=Habgood |first5=Mark D. |last6=Møllgård |first6=Kjeld |last7=Bauer |first7=Hans-Christian |date=2014 |title=The rights and wrongs of blood-brain barrier permeability studies: a walk through 100 years of history |journal=Frontiers in Neuroscience |volume=8 |page=404 |doi=10.3389/fnins.2014.00404 |pmid=25565938 |pmc=4267212 |issn=1662-453X |doi-access=free }}</ref> Stern was a Russian scientist who published her work in Russian and French. Due to the language barrier between her publications and English-speaking scientists, this could have made her work a lesser-known origin of the term.

All the while, [[bacteriologist]] [[Paul Ehrlich]] was studying [[staining]], a procedure that is used in many [[histology|microscopy studies]] to make fine biological structures visible using chemical dyes.<ref name="saunders">{{cite journal | vauthors = Saunders NR, Dziegielewska KM, Møllgård K, Habgood MD | title = Markers for blood-brain barrier integrity: how appropriate is Evans blue in the twenty-first century and what are the alternatives? | journal = Frontiers in Neuroscience | volume = 9 | pages = 385 | year = 2015 | pmid = 26578854 | pmc = 4624851 | doi = 10.3389/fnins.2015.00385 | doi-access = free }}</ref> As Ehrlich injected some of these dyes (notably the [[aniline dye]]s that were then widely used), the dye stained all of the [[organ (anatomy)|organs]] of some kinds of animals except for their brains.<ref name=saunders/> At that time, Ehrlich attributed this lack of staining to the brain simply not picking up as much of the dye.<ref name=":0" />

However, in a later experiment in 1913, [[Edwin Goldmann]] (one of Ehrlich's students) injected the dye directly into the [[cerebrospinal fluid]] of animal brains. He found then the brains did become dyed, but the rest of the body did not, demonstrating the existence of a compartmentalization between the two. At that time, it was thought that the blood vessels themselves were responsible for the barrier, since no obvious membrane could be found.