Stress and the BBB
May as well combine two interests here.
1: Brain Res. 2001 Jan 5;888(1):117-127. Acute stress increases permeability of the blood-brain-barrier through activation of brain mast cells. Esposito P, Gheorghe D, Kandere K, Pang X, Connolly R, Jacobson S, Theoharides TC. Departments of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA. Disruption of the blood-brain-barrier (BBB) is important in the pathophysiology of various inflammatory conditions of the central nervous system (CNS), such as multiple sclerosis (MS), in which breakdown of the BBB precedes any clinical or pathological findings. There is some evidence that relapsing-remitting MS attacks may be correlated with certain types of acute stressful episodes. Stress typically activates the hypothalamic-pituitary-adrenal (HPA) axis through the release of corticotropin releasing hormone (CRH), leading to production of glucocorticoids that down regulate immune responses. However, acute stress also has pro-inflammatory effects that appear to be mediated through activation of mast cells. Here we show that acute stress by immobilization increased permeability of rat BBB to intravenous 99Technetium gluceptate (99Tc). This effect was statistically significant in the diencephalon and the cerebellum, while it was absent in the cerebral cortex where there are not mast cells. Immobilization stress also induced activation of mast cells in diencephalon, the site where most mast cells are found in the rat brain. Both BBB permeability and mast cell activation were inhibited by the 'mast cell stabilizer' disodium cromoglycate (cromolyn). These results expand the pathophysiology of mast cells and implicate them in CNS disorders, that may possibly be induced or exacerbated by stress. PMID: 11146058 [PubMed - indexed for MEDLINE] |
So a reasonable hypothesis...
...might be that one of a number of factors leading to PD is that our individual responses to stress result in varied amounts of hormonal release which lead to individualized disruption of the BBB.
Toxins find their way from the gut by way of its similarly compromised barrier into the bloodstream and thence into the brain. Among those toxins are bacterial LPS as well as metals, pesticides, etc. LPS potentiates the toxicity of mercury, rotenone, etc. In previously sensitized individuals, LPS activates the microglia (brain immune cells) leading to over-reaction and self harm. One of the higher concentrations of microglia is in the substantia nigra. This is not the whole tapestry, but seems reasonable as one of the primary threads. |
an excellent site
http://www.fi.edu/brain/stress.htm
The site covers a lot more than stress. Clear, understandable, cool pictures, good design too. If you barely understand what your neuro is talking about, a half hour here will bring you up to speed. Spend a couple of hours and you will know more than he does. |
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