Hi Rick,
You are quite right, blood pressure must be important, it is like volts and amps. a high voltage is the pressure component, and amps are the quantity. Higher blood pressure presumably helps push a larger molecule through.
It is significant that hypertension drugs improve matters, and in addition to reducing blood pressure, they reduce BBB porosity.
Mrsd,
This is the direction we need to examine. Zonulin is a signaling protein that transiently opens the BBB to let in a medication that can't normally pass.
This is of course is the opposite way we are interested in, we need such a protein or other compound which will cause a permanent reduction in permeability. I wonder do patients given zonulin suffer very transient freezing or movement side effects?? Maybe the increase in permeability is low eg 140 on my imaginary scale, so no PD symptoms occur.
Intersting about the H2 agonists crossing the highly permeable BBB's of the elderly and causing delirium. The medical profession has until recently never considered the dide effects caused by the BBB not remaining impervious to everything it normally won't pass. See the cause of Gulf War syndrome.
http://www.sciencenews.org/pages/pdf...4/15024-10.pdf

serving
in the Persian Gulf War suffered adverse side effects from the inoculation. These reactions
puzzled physicians, who had expected the blood-brain barrier to keep this drug—like many
other chemicals circulating in the blood—out of the brain.
Now, an Israeli study suggests that stress may have temporarily opened the blood-brain barrier.
“It was surprising—we saw quite large amounts of brain penetration,” says Hermona Soreq of
the Hebrew University in Jerusalem, a coauthor of the report in the December NATURE MEDICINE.
During the Gulf War, Soreq and her colleagues at Tel Aviv University studied a unit of soldiers
given pyridostigmine, a drug that attaches to receptors on nerves outside the central nervous
system. When chemical weapons invade the body, they can’t bind to the occupied receptors,
which limits their ability to cause damage.
Usually, only small amounts of pyridostigmine cross the blood-brain barrier. However, nearly
one-quarter of the inoculated soldiers complained of mild neurological side effects, such as
headaches and drowsiness. When the researchers inoculated another group of soldiers during
peacetime, only 8 percent reported symptoms. “Our suspicion was that the stress associated
with war made the difference,” says Soreq.
The physicians also injected the drug into mice that had been forced to swim for two 4-
minute intervals and into unstressed mice. The researchers found that it took over 100 times
more pyridostigmine to penetrate the brains of unstressed mice as the brains of stressed mice.
Tests using a larger molecule, a blue dye, showed a similar effect.
“The important thing is finding a drug that should not have crossed the blood-brain barrier
and apparently did, under conditions of stress,” comments Israel Hanin of Loyola University of
Chicago in Maywood, Ill., who advises physicians to consider reducing the drug dosages they
prescribe to stressed patients.

Ron