Researchers at The Medical College of Wisconsin in Milwaukee say that even though scientists have known that people have different cardiovascular sensitivity to anaesthesia because of which some collapse even when low doses are administered, the mechanism responsible for this susceptibility is not clear.
"By identifying a genetic susceptibility for cardiovascular collapse to low dose propofol, our findings may provide a key to better understand the underlying cause of the mysterious death of Michael Jackson," says Dr. Richard Roman, a professor of Physiology and director of the Kidney Disease Center at the College.
To find the genetic mechanism that causes this reaction, Dr. Thomas A. Stekiel and Dr. Anna Stadnicka, both associate professors of Anaesthesiology, administered the anaesthetic propofol to a strain of rat (Dah S), which is very sensitive to anaesthetics versus Brown Norway (BN) rats that are quite resistant.
Upon extensive genetic analysis, the researchers found that a small region on chromosome 13 contained the genetic switch responsible for the difference in the response of these strains to anaesthesia.
They say that this region also contains the renin gene, an important blood pressure controller.
"The next step is to identify the exact gene and see if it is also responsible for cardiovascular collapse with propofol in humans. We can then test which persons with this gene would be sensitive to anesthesia and prevent deaths and accidents due to cardiovascular collapse in the operating room," says Dr. Carol Moreno Quinn, co-author at the Medical College's Human and Molecular Genetics Center at the College.
The researchers said that their new findings supported an earlier study that showed that propofol has greater impact on vascular smooth muscle in the hypertensive salt-sensitive Dahl rats as compared to the normotensive Brown Norway rats, and that chromosome 13-associted genes are responsible for variable responses to propofol.
A research article describing the study has been published in the Journal of Pharmacology and Experimental Therapeutics with an editorial commentary.