The association of the inhaled anesthetic isoflurane with Alzheimer's-disease-like changes in mammalian brains may be caused by the drug's effects on mitochondria, the structures in which most cellular energey is produced. In a study that will appear in Annals of Neurology and has received early online release, Massachusetts General Hospital (MGH) researchers report that administration of isoflurane impaired the performance of mice on a standard test of learning and memory - a result not seen when another anesthetic, desflurane, was administered. They also found evidence that the two drugs have significantly different effets on mitochondrial function.
"These are the first results indicating that isoflurane, but not desflurane, may induce neuronal cell death and impair learning and memory by damaging mitochondria," says Yiyin (Laura) Zhang, MD, a research fellow in the Department of Anesthesia, Critical Care and Pain Medicine and the study's lead author. "This work needs to be confirmed in human studies, but it's looking like desflurane may be a better anesthetic to use for patients susceptible to cognitive dysfunction, such as Alzheimer's patients."
Previous studies have suggested that undergoing surgery and general anesthesia may increase risk of Alzheimer's, and it is well known that a small but significant number of surgical patients experience a transient form of cognitive dysfunction in the postoperative period.