"We also think without the B receptor function, your A's go a little bit crazy," Pollock said. Not only do the A's constrict, they promote inflammation, which can further damage blood vessels. In fact, a high-salt diet can cause even B receptors to behave badly, said Dr. Jennifer Pollock, MCG biochemist and a project leader.
Across the country, Dr. Donald Kohan, nephrologist and physiologist at the University of Utah, wants to figure out what prompts the kidneys to make more endothelin in the face of a high-salt diet. He is studying kidney cells to examine how endothelin production changes and ideally learn why. The goal, again, is drug therapies to inspire this natural phenomenon.
The results when A receptors go unchecked include stiff, tortuous blood vessels; a thick boggy pumping chamber in the heart; and other major organ damage that includes the kidney.
"The consequences are measurable targets," said Dr. Edward Inscho, MCG physiologist and a project leader, noting that treatments are available but "preventing it from occurring is something we are not very good at yet."
To help put the pieces together, Inscho is focusing on how blood vessels that feed directly into kidney filters react to a high-salt diet. Blood, containing salt, continuously flows through the kidneys. The researchers have seen that excess salt increases B receptor expression, which should help the kidneys filter more sodium then get rid of it.
"If you filter more, you have more salt available for excretion," Inscho said. He wants to know what's happening with A and B receptors inside the tiny vasculature of the kidneys. He's using B-deficient rats and drugs that block either receptor to get a better idea about both. The idea is to figure out not just how they normally work but how the system becomes dysfunctional in hypertension. "I think we are beginning to understand how the B rece
|Contact: Toni Baker|
Medical College of Georgia