Talk:Blood–brain barrier/Archive 1

Ecstasy
New research indicates that the drug ecstasy "may damage" the blood-brain barrier: http://www.newscientist.com/article.ns?id=dn8314

Too tired to write it up. Have at it, boys. (Unsigned. By 71.246.233.74, 03:49, 15 November 2005.)

Blood-brain barrier
Has anybody have any notes on affects of cell-phones on the Blood Brain Barrier?

hydkat 05:52, 19 December 2005 (UTC)

See http://www.ehponline.org/docs/2003/6039/abstract.html.

For orally administered drugs there seems to be some guidelines, see: http://en.wikipedia.org/wiki/Lipinski's_Rule_of_Five

Also try, Proudfoot, Bioorganic and Medicinal Chemistry Letter 15, 1087

/mfg Have anyone info what happen to BBB during traumatic stress? I suspect my Multiple Sclerosis was a result from a traumatic accident. —Preceding unsigned comment added by 120.28.209.238 (talk) 04:28, 11 January 2010 (UTC)

Drugs Targeting the Brain
If dye can travel from the spine to the brain, why can't we administer drugs to the brain by injecting it into the spine?


 * A. Because getting needles stuck into cerebral fluid not only is dangerous, but it really hurts.

I am not an expert; but I found some drugs / antibiotics can cross the blood brain barrier.

We also need to mention the action of anti-psychotic medication as well. — Preceding unsigned comment added by Amishra222 (talk • contribs) 01:27, 21 April 2011 (UTC)

Comment: drugs injected into the spinal CSF can make their way up to the subarachnoid CSF (the CSF covering the outer surface of the brain) and from there pass into the blood stream via the arachnoid granulations and arachnoid villi (depending on species). Very little drug would be able to move upstream against the flow of CSF through the aqueduct to make it into central brain regions (ventricles). There is a barrier at the level of the surface of the brain that restricts passage from the subarachnoid CSF into the brain. — Preceding unsigned comment added by HaveNoIdea (talk • contribs) 06:26, 15 August 2016 (UTC)


 * Decades back (1970s), I was a Navy corpsman assigned to a Navy medical research facility, & our work involved mainly the BBB.
 * There was in the air results of experiments done elsewhere that showed that deep-brain cancer tumors could be destroyed by enzymes injected into the bloodstream after permeation of the BBB by repeated exposure to hyperbaric (c. 3 atm) oxygen. However, the conclusion was that those experiments could not be replicated, & so what appeared to be a major breakthrough was cast aside. I have read no more about killing off brain tumors by permeating the BBB. Has anyone else? BubbleDine (talk) 03:02, 1 September 2019 (UTC)

Permeability to alcohol
I mentioned in the article that the BBB is permeable to alcohol, but I didn't go into details explaining thats why the feeling of being drunk affects people when they drink (having alcohol in their blood-stream). Darwin&#39;s Bulldog 16:54, 4 June 2006 (UTC)

Comment: ethanol is almost as soluble in lipids as it is in water (LogP octanol value is around -0.3). It can enter the brain by diffusing through the plasma membranes of cerebral endothelial cells (the cells that form the walls of brain blood vessels). — Preceding unsigned comment added by HaveNoIdea (talk • contribs) 06:30, 15 August 2016 (UTC)

L-DOPA?
"[...] the endothelial cells metabolize certain molecules to prevent their entry into the central nervous system; the most-studied example of this is L-DOPA."

According to the L-DOPA Wikipedia entry, its is dopamine itself that is unable to traverse the BBB, and it is the ability of L-DOPA to cross the BBB that is responsible for its mechanism of action.

What's the deal? -- Mark Lundquist 00:35, 17 August 2006 (UTC)


 * Yeah L-Dopa is used for Parkinson's as it can get through the BBB. You're right


 * Actually, the L-DOPA is able to cross the BBB but it gets degraded in the cells by monoamine oxidase, and thus is not accessible to brain neurones. This is why Parkinsons's treatment with L-DOPA is always given coincidently with MAOIs (monoamine oxidase inhibitors). (Kandel, Principles of neuroscience) —Preceding unsigned comment added by Siamesesecret (talk • contribs) 14:00, 15 May 2009 (UTC)

Comment: L-Dopa is less lipid soluble than dopamine, but it can cross the blood-brain barrier via the L-system amino acid transporter (large neutral amino acid transporter). Decarboxylases (enzymes that cut off the carboxylic acid group) create dopamine from L-Dopa. This can happen in the blood and so carbidopa is often administered at the same time to keep blood carboxylases busy. Once inside a cerebral endothelial cell, L-Dopa can be subject to phase I metabolism, but the extent to which this restricts entry into brain is governed by how much drug is administered vs the capacity of cells to metabolise it. The dopamine when it gets into the brain interstitial fluid is taken up by dopaminergic neurons and added to that made by the neuron and stored in its vesicles. Thus when the neuron is active, more dopamine than normal is released into the synaptic cleft to stimulate a greater number of post-syanptic receptors on more neurons (provides a greater effect). Initially, L-Dopa therapy works very well in Parkinsons (read Awakenings by Oliver Sacks), but eventually it becomes ineffective as more and more dopaminergic neurons are lost leaving fewer to take up the dopamine. — Preceding unsigned comment added by HaveNoIdea (talk • contribs) 06:40, 15 August 2016 (UTC)

BAFFLING REDIRECTION?
This is the sort of thing that undermines Wikipedia's reputation:

"Blood-brain Barrier

(Redirected from Blood-cerebrospinal fluid barrier)

The blood-brain barrier (abbreviated BBB, not to be confused with the blood-cerebrospinal fluid barrier... )"

Well played, Wikipedia, well played. Hey, I'm not the only one who came here to point this out. Any experts want to start an article on the blood-CSF barrier, if, indeed, it is disctinct from the BBB?


 * Whoever wrote the above clearly does not understand the concept of taking any kind of measures "for the time being". The blood-brain barrier and the blood-cerebralspinal fluid barrier clearly have many aspects in common with each other. Knowing a good deal about one clearly helps one to know something about the other.
 * Thus, given the absence of an article on the "blood-cerebralspinal fluid barrier", it is better to redirect from a request for that article to the article on the blood-brain barrier than to give nothing at all. Some people don't understand such ideas nowadays, but there is an old, old saying about having half a loaf of bread is better than no loaf at all - thus why go about whining about not having a full loaf when you do have half a loaf?
 * At some future time, when someone creates an article on the "blood-cerebralspinal fluid barrier" (if such a thing does exist), then the redirects can be modified then.98.67.164.50 (talk) 14:53, 18 November 2009 (UTC)


 * If an article is missing or redirecting wrong, you're more than welcome to create that article. As you clearly seem to be of the opinion that you know very much about this specific area, then why not take the opportunity to contribute? Articles won't make them self you know, even if it might seem so when you click and everything just pops up. Stop complaining and get to work!  —Preceding unsigned comment added by Tamte (talk • contribs) 18:57, 10 January 2010 (UTC)

Mistake or just a typo?
Glial cells surrounding capilaries in the brain pose a secondary hindrance to hydrophillic molecules, and the low concentration of interstitial proteins in the brain prevent access by hydrophilic molecules.

Hydrophillic and hydrophilic. Is there just an extra l or should one of these be hydrophobic instead? --TuukkaH 20:04, 17 November 2006 (UTC)


 * Somebody fixed the typo, but does this sentence now make sense? I have no expertise here at all, but from the semantics, it certainly seems as if one of these words should be hydrophobic (I would guess the first one). Would someone who knows please fix this (if it is, in fact, incorrect)?Eaglizard 18:50, 6 May 2007 (UTC)

Comment: hydrophilic (single l) is the most commonly used variant. However, the statement that glial cells prose a secondary hinderance is incorrect. They do not impede the movement of compounds at all. Several studies have shown that dyes injected into the brain interstitial fluid pass beyond the glial cells and astrocytic endfeet to reach the abluminal surface of brain endothelial cells (blood vessel walls). The appearance of a close fit between astrocyte endfeet and cerebral endothelial cells is mostly an artefact of tissue fixation. Brain tissue shrinks on fixation and the extracellular space is mostly lost. Rapid careful freezing can prevent much of this shrinkage and preserve the space.

Ependymal cells??
This entry had the following in the opening section: "Astrocytes, a type of glial cell specific to the central nervous system, form a tight barrier between the blood capillaries of the brain and the ependymal cells lining the ventricles of the brain." I cannot see the relevance of this. Astrocytes support the epithelial cells of the BBB, but are not an essential part. I am deleting this sentence and adding something more relevant. —The preceding unsigned comment was added by Benbest (talk • contribs) 06:05, 17 February 2007 (UTC).
 * Oops! --Ben Best 13:06, 17 February 2007 (UTC)

Comment: correct. barrier properties are present in cerebral blood vessels BEFORE astrocytic end feet are present. See comment above re: hydrophilic about dye studies showing no barrier between endfeet and endothlial cells — Preceding unsigned comment added by HaveNoIdea (talk • contribs) 06:49, 15 August 2016 (UTC)

Bit of cleanup
I rewrote most of the sections of this article slightly to make them more readable to the lay audience (i.e., myself). As always, I tried to avoid changing the factual substance of anything, as I am completely inexpert in this field. I have faith any errors I have introduced will be quickly healed. :) I hope my complete rewrite of the first (and most important) paragraph is satisfactory, in particular. It does seem to me that the last sections (the various specific diseases) devolve into heavily obscure jargon, but I don't feel qualified to mess with those. Eaglizard 18:50, 6 May 2007 (UTC)


 * I rewrote the introduction of this article to clear up the nature of the BBB (to address Kvng's critique) and its function (to address my own). Please proof my edits.  PVSpud (talk) 13:24, 21 June 2009 (UTC)
 * Thanks, guys! Really appreciate it! Torrent97 (talk) 06:39, 11 February 2021 (UTC)

When is the blood-brain barrier in place?
At birth, or later? —Preceding unsigned comment added by 71.194.21.50 (talk) 13:31, 27 September 2007 (UTC)


 * How about before birth? Fetal human brains might need protection from organic poisons that are ingested by the mother. However, those my be blocked by the placenta -- but two layers of protection are better than just one.98.67.164.50 (talk) 14:37, 18 November 2009 (UTC)


 * Studies show that it's more permeable at a young age, but the study cited about rabbits make it seem like age is irrelevant for humans when it's not. — Preceding unsigned comment added by 96.236.219.195 (talk) 05:20, 27 April 2016 (UTC)

Comment: the blood-brain barrier is present from the time blood vessels first start to grow into the neuropil. They are tight to circulating dyes and tracers from very early in embryonic life. Studies showing increased permeability are an artefact of injecting more volume of dye or high concentrations of dye. Multiple studies using sensible volumes and concentrations have confirmed blood vessels are tight from the very earliest stages of development. The observed presence of ion gradients between blood and brain interstitial fluid during development can only happen if there is a tight barrier. — Preceding unsigned comment added by HaveNoIdea (talk • contribs) 06:54, 15 August 2016 (UTC)

Retina?
There was a sentence fragment in the introduction that looked like it once contained information but no longer made any sense. I deleted it, but the author should feel free to replace the information. (see the diff of my last edit)

mcs (talk) 01:34, 12 November 2008 (UTC)

MCOTW
This article is now MCOTW. It is a bit uncommon for anatomy and physiology articles to become MCOTW, and we don't actually have much precedent. What I do see is that the article needs a lot of cleanup (there are multiple sections called "physiology"), and I don't think we should be discussing the role of the BBB in every single disease. We need to discuss various parallel concepts (blood-retina barrier, blood-testicle barrier, blood-nerve barrier). And rather than nanoparticles we should be focussing on actual medicines... JFW | T@lk  15:42, 18 January 2009 (UTC)


 * Well, not an awful lot has happened. Boring. I'm closing this MCOTW early. Better next time. JFW | T@lk  10:31, 1 February 2009 (UTC)

Head image
What do you think of the image I added? I quite like it, but perhaps not to everyone's tastes. Cheers, Basie (talk) 05:31, 19 January 2009 (UTC)


 * Also note http://commons.wikimedia.org/wiki/File:Tightjunction_BBB.jpg. Basie (talk) 05:33, 19 January 2009 (UTC)

Where is it?
After careful reading, I gather that the BBB is an integral part of the capillaries delivering blood to the brain. Those like me who might come to this article under the impression that the BBB is an organ in the head somewhere will have a hard time getting themselves properly oriented. The article doesn't clearly locate the BBB. It does describe where the barrier is located at a cellular level. It does indicate that it is part of "CNS vessels" --Kvng (talk) 15:08, 27 May 2009 (UTC)


 * Yes, this article does need to state clearly that the blood-bran barrier exists in the linings of almost all of the capillaries of the human brain, and in 100% of the capillaries of the cerebrum. No beating around the bush is acceptable.98.67.164.50 (talk) 14:34, 18 November 2009 (UTC)

Yes, it should be stated that the blood-brain barrier is the tight junctions between adjacent cerebral endothelial cells that form the walls of brain blood vessels. — Preceding unsigned comment added by HaveNoIdea (talk • contribs) 06:55, 15 August 2016 (UTC)

Basic Permeability and Anatomy
I think this article could benefit greatly from a simple explanation of what the barrier blocks and where it is located. I believe the cerebral capillaries are contained in the choroid plexus and that the barrier is permeable to hydrophobic molecules (which passively diffuse?) while hydrophilic molecules (e.g. glucose) require active transport. The link http://electricwords.emfacts.com/csiro/chapter8.html helped with the permeability. —Preceding unsigned comment added by PVSpud (talk • contribs) 13:08, 21 June 2009 (UTC)


 * That's a rather absurd statement to make: "cerebral capillaries are contained in the" (any specific location at all). Cerebral capillaries are located, spaced rather tightly, everywhere at all in the cerebrum. Everywhere in the human cerebrum there is a high demand for oxygen and sugar by the brain cells, and a correspondingly-high output of carbon dioxide and other metabolic products that need to be removed. Thus, there is a strong need for capillaries tightly-spaced, everywhere in the cerebrum. In addition, there is the same kind of high demand for these inputs and outputs everywhere in the human brain, such as in the cerebellum and in all of the "lower" or "older" parts of the brain from the evolutionary point-of-view. (I just call them the "R-complex" as Carl Sagan did in his Pulitzer Prize-winning book, The Dragons of Eden.
 * To summarize simply, cerebral capillaries are located everywhere within the cerebrum, and there is also a tight network of capillaries everywhere else in the human brain.98.67.164.50 (talk) 14:31, 18 November 2009 (UTC)

Image
Could be cropped and used:
 * File:Schematic drawing of cellular regulation of extracellular glutamate concentrations.jpg -- C opper K ettle  20:02, 17 October 2009 (UTC)

--

BBB vs blood-CSF barrier
OK the page is WRONG, you need to talk about csf barrier, it is different than the endothelial bloood brain barrier. The begininng of the article confused me. It needs to be fixed immediatly. MD SIDHU, March 2010 —Preceding unsigned comment added by Md Sidhu (talk • contribs) 15:18, 15 March 2010 (UTC) Bold textang pangit mo biboy --180.191.25.34 (talk) 10:33, 8 May 2010 (UTC) ang pogi ni justin

I agree. There is inconsistency in the article in that the opening sentence refers to the BBB as the barrier between the blood and CSF, and then goes on to talk about endothelial cells & astrocytes. If my understanding is correct, the BBB refers to the blood-BECF (brain extracellular fluid) barrier, not the blood-CSF barrier. The BBB involves the tight-junction endothelium & astrocytes, whereas the blood-CSF barrier involves more leaky endothelium & ependymal cells of the choroid plexuses. 96.247.98.242 (talk) 00:00, 3 February 2011 (UTC)

I'm a non-expert in medicine in general and the first two sections of the article were pretty confusing to me (history and physiology). The first paragraph talks about Goldmann finding brain stains via CSF injections which contrasted with the earlier non-staining via blood result. The logical conclusion to most readers like me would be that BBB is indeed blood-CSF. The very next section contradicts this (``The BBB is distinct from the quite similar blood–cerebrospinal-fluid barrier''). Could an expert please rewrite to clarify? — Preceding unsigned comment added by 2607:F470:8:1050:3052:A263:79E:30F9 (talk) 19:35, 13 February 2013 (UTC)

typo in heading?
It says 'molecules into the CSF, while' Is this supposed to be CNS? CSF isnt expanded anywhere. 83.25.87.166 (talk) 20:34, 14 February 2011 (UTC)

nevermind, found it: CSF -> Cerebrospinal fluid 83.25.87.166 (talk) 20:41, 14 February 2011 (UTC)

Sketch of the BBB
Could anyone take some time to translate the schematic there? It's in German and I would translate it of I spoke it, but I don't.  — Preceding unsigned comment added by Ianfitz100 (talk • contribs) 21:00, 20 February 2012 (UTC)

Material of blood brain barrier
Can someone confirm the blood brain barrier is made of endothelial cells, and is not fluid? 129.180.166.53 (talk) 13:36, 10 June 2012 (UTC)

The blood-brain barrier is the tight junctions between endothelial cells which form the blood facing wall of brain blood vessels. These tight junctions prevent compounds from passing between cells. With this route closed, compounds have to find a transcellular route to get across into the brain (i.e. a carrier system, transporter or be lipid soluble and not intercepted by active efflux pumps like pgp). — Preceding unsigned comment added by HaveNoIdea (talk • contribs) 06:58, 15 August 2016 (UTC)

Prions
Can anyone add a discussion of how Prions end up passing through the BBB (if they do)? — Preceding unsigned comment added by 204.12.153.65 (talk) 23:33, 30 August 2012 (UTC)

permeability of short-, medium- and long-chain fatty acids
Is there data on the permeability of short-, medium- and long-chain fatty acids? Echinacin35 (talk) 12:09, 3 February 2013 (UTC)

permeability of lactose and galactose
Is there data on the permeability of lactose and galactose? Echinacin35 (talk) 12:10, 3 February 2013 (UTC)

This article may be expanded with text translated from the corresponding article in German and Russian
This article may be expanded with text translated from the corresponding article in German and Russian. This notice is also at the top of the discussion page. Took it away from the top of the article as it's annoying for the readers. 173.225.249.190 (talk) 13:21, 10 February 2016 (UTC)

A Rabies citation?
The section on Rabies is tagged as possible Original Research; I found a reference that could substantiate the entry, but since I didn't make the original entry, I don't know whether the entry came from this reference or not, so I didn't add the citation. It does seem relevant anyway, so here it is (as an abstract from the Journal): Antiviral Research, Volume 110, October 2014, Pages 132–141, via:  http://www.sciencedirect.com/science/article/pii/S0166354214002125 UnderEducatedGeezer (talk) 04:28, 8 April 2016 (UTC)

boreliosis
What about Lyme disease (Lyme borreliosis)? — Preceding unsigned comment added by IlluminatiX (talk • contribs) 20:32, 25 June 2016 (UTC)