 |
|
Penn researchers use honeybee venom toxin to develop a new tool for studying hypertension
September 18, 2008PHILADELPHIA - Researchers at the University of Pennsylvania School of Medicine have modified a honeybee venom toxin so that it can be used as a tool to study the inner workings of ion channels that control heart rate and the recycling of salt in kidneys. In general, ion channels selectively allow the passage of small ions such as sodium, potassium, or calcium into and out of the cell.
The study, published in the Proceedings of the National Academy of Sciences, is from the laboratory of Zhe Lu, M.D, Ph.D., Professor of Physiology and a Howard Hughes Medical Institute Investigator, who looked at the action of a natural bee toxin on inward-rectifier potassium channels, Kir channels for short, to identify new approaches to treat cardiovascular disease.
The honeybee venom toxin, called tertiapin, or TPN, stops the flow of potassium ions across cell membranes by plugging up the opening of Kir channels on the outside of cells. Kir channels in kidneys are potential new targets for treating hypertension. "The clue comes from patients with genetic defects in these channels who lose a lot of sodium because it cannot be effectively reabsorbed and thus have low blood pressure," notes Lu. "An inhibitor specifically against these kidney channels will allow this idea to be tested."
Developing a specific inhibitor for one type of Kir channel has been challenging because the target site is very similar among different types of Kir channels. For example, while TPN inhibits Kir type 1 channels in kidney cells, it also inhibits other types of Kir channels in heart cells. After more than a decade, Lu and his colleagues succeeded in bioengineering a TPN that selectively inhibits Kir channels important for salt recycling in kidneys.
By introducing two mutations into TPN, they engineered a variant, called TPNLQ, which stems the flow of potassium ions in renal Kir type 1 channels at low concentrations, and with a 250-fold sensitivity over six other types of Kir channels.
The development of TPNLQ demonstrates that a highly specific inhibitor of potassium channels can be engineered. TPNLQ can now be used as a tool to prove the concept, in animal studies, that reducing salt reabsorption by plugging up renal Kir type 1 potassium channels is a potential new way to treat hypertension.
University of Pennsylvania School of Medicine
Developing a specific inhibitor for one type of Kir channel has been challenging because the target site is very similar among different types of Kir channels. For example, while TPN inhibits Kir type 1 channels in kidney cells, it also inhibits other types of Kir channels in heart cells. After more than a decade, Lu and his colleagues succeeded in bioengineering a TPN that selectively inhibits Kir channels important for salt recycling in kidneys.
By introducing two mutations into TPN, they engineered a variant, called TPNLQ, which stems the flow of potassium ions in renal Kir type 1 channels at low concentrations, and with a 250-fold sensitivity over six other types of Kir channels.
The development of TPNLQ demonstrates that a highly specific inhibitor of potassium channels can be engineered. TPNLQ can now be used as a tool to prove the concept, in animal studies, that reducing salt reabsorption by plugging up renal Kir type 1 potassium channels is a potential new way to treat hypertension.
University of Pennsylvania School of Medicine
Potassium Current Events and Potassium News RSSNew 'control knobs' for stem cells identified
Natural changes in voltage that occur across the membrane of adult human stem cells are a powerful controlling factor in the process by which these stem cells differentiate, according to research published by Tufts University scientists.
Calcium and vitamin D may not be the only protection against bone loss
Diets that are high in protein and cereal grains produce an excess of acid in the body which may increase calcium excretion and weaken bones, according to a new study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).
Nutrients in water may be a bonus for agriculture
Agriculture producers may find they don't have to bottle their water from the Seymour Aquifer in the Rolling Plains to make it more valuable, according to Texas AgriLife Research scientists.
Potassium loss from blood pressure drugs may explain higher risk of adult diabetes
Johns Hopkins researchers have discovered that a drop in blood potassium levels caused by diuretics commonly prescribed for high blood pressure could be the reason why people on those drugs are at risk for developing type 2 diabetes.
Where there's wildfire smoke, there's toxicity
The health threat to city dwellers posed by Southern California wildfires like those of November 2008 may have been underestimated by officials.
Moderate use averts failure of type 2 diabetes drugs in animal model
Drugs widely used to treat type 2 diabetes may be more likely to keep working if they are used in moderation, researchers at Washington University School of Medicine in St. Louis have found in a study using an animal model.
Forsyth scientists trigger cancer-like response from embryonic stem cells
Scientists from The Forsyth Institute, working with collaborators at Tufts and Tuebingen Universities, have discovered a new control over embryonic stem cells' behavior.
Models of eel cells suggest electrifying possibilities
Engineers long have known that great ideas can be lifted from Mother Nature, but a new paper by researchers at Yale University and the National Institute of Standards and Technology (NIST) takes it to a cellular level.
Argonne scientists peer into heart of compound that may detect chemical, biological weapons
A light-transmitting compound that could one day be used in high-efficiency fiber optics and in sensors to detect biological and chemical weapons at long distance almost went undiscovered by scientists because its structure was too difficult to examine.
Blood Pressure Drug Combination Reduces Heart Attack Deaths
Thousands of patients with high blood pressure could benefit from changing their drug treatment regimen to reduce their risk of cardiac death.
More Potassium Current Events and Potassium News Articles
| Glucose, insulin, potassium, and the heart: Selected aspects of cardiac energy metabolism by Richard J Kones | |
 | Everything You Always Wanted to Know About Potassium but Were to Tired to Ask by Betty Kamen Proving a clear connection between potassium deficiency andssure, which affects two-thirds of Americans over 60, Dr. Kamen then proceeds to outline a healthy path to balancing sodium and potassium levels throughout life. (Nutrition Encounter,... |
 | Notes On Gold Extraction By Means Of Cyanide Of Potassium, MacArthur-Forrest Patents, As Carried Out On The Witwatersrand Gold Fields, Transvaal, South Africa by W. R Feldtmann |
| Sodium and Potassium in Foods and Drugs | |
 | How To Choose Potassium Rich Foods by Quick Easy Guides Before we talk about how to get more potassium into your diet, let's quickly touch on why you should. First of all, your heart simply won't beat without potassium -- that's...Written by experts in the field, Quick Easy Guides share little-known trade secrets and helpful hints to get you moving in the right direction.Quick Easy Guides gives you books you can judge by the cover. Our books are... |
| Potassium: Physiological and clinical importance (Directions in cardiovascular medicine) by Gerhard H Giebisch | |
 | ISO 2466:1973, Potassium hydroxide for industrial use -- Sampling -- Test sample -- Preparation of the main solution for carrying out certain determinations by ISO TC 47 Provides certain indications relating to the sampling and indicates the conditions under which the test sample should be prepared The special properties which make particular precautions essential such as hygroscopic characteristics, absorption of carbon dioxide, corrosive action on containers, should be stressed. The preparation of the main solution is carried out by dissolution of the test... |
 | The 2007 Import and Export Market for Potassium Hydroxide (Caustic Potash) and Peroxides of Sodium or Potassium in Italy by Parker, Philip M. On the demand side, exporters and strategic planners focusing on potassium hydroxide (caustic potash) and peroxides of sodium or potassium in Italy face a number of questions. Which countries are supplying potassium hydroxide (caustic potash) and peroxides of sodium or potassium to Italy? How important is Italy compared to others in terms of the entire global and regional market? How much do the... |
| K rations: a low-potassium diet is essential for transition cows.: An article from: Dairy Today by Ed Haag This digital document is an article from Dairy Today, published by Farm Journal Media on October 1, 2002. The length of the article is 651 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.Citation DetailsTitle: K... | |
| Salt of the earth. (salt and potassium lactase usage): An article from: Food Processing by Bert De Vegt This digital document is an article from Food Processing, published by Putman Media, Inc. on October 1, 1997. The length of the article is 669 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.From the supplier: Meat... |
| © 2008 BrightSurf.com |