Updated

The head of the Veterans Affairs Department said he will ask researchers to investigate possible links between sarin gas and symptoms seen in Persian Gulf War veterans after a study found the nerve gas affected behavior and organ functions in laboratory mice.

VA Secretary Anthony Principi said he will ask the Institute of Medicine to provide him with a report of whether findings in the study "hold true for humans in the Persian Gulf" who might have been exposed to sarin.

"I understand how it can be so frustrating for service members who feel their service in the gulf might have caused their illnesses," Principi said Thursday.

Veterans of the 1991 Gulf War have suffered from illnesses they believe linked to their service in Gulf. Among reported symptoms are chronic fatigue, diarrhea, migraines, dizziness, memory problems, loss of muscle control and loss of balance.

For years, many scientists have blamed stress. Veterans and some researchers, however, attribute the health problems to toxic substances the veterans encountered in the Gulf, including sarin. Others suggest it may be a combination of factors.

The Institute of Medicine has been reviewing research of substances considered possible culprits in illnesses suffered by Gulf War veterans. Thus far it has reported that not enough scientific information exists to determine whether exposure to low levels of sarin nerve gas had long-term health effects in people.

Sarin nerve gas is a deadly toxin that quickly kills its victims at high levels, but little is known about its effects when people are exposed to nonlethal doses or doses that have no immediate effects.

The Associated Press reported in December that an Army-sponsored study done by Lovelace Respiratory Research Institute in Albuquerque, N.M., suggested that low-level exposure has some effect over time in lab mice, including causing changes to structures of the brain critical for memory and cognition.

The Pentagon says about 130,000 Persian Gulf War veterans were exposed to sarin nerve gas when U.S. troops destroyed an Iraqi weapons depot in Khamisiyah in 1991. Some of the weapons contained sarin gas, and some veterans believe other exposures occurred as well.

Dr. Robert Haley, an epidemiologist with the University of Texas Southwestern Medical Center at Dallas, has published almost two dozen studies suggesting that some Gulf War veterans' illnesses are linked to brain damage resulting from exposure to toxins such as sarin.

Haley said Principi's request for a review of the study is the right move. "He is doing everything he can to short-circuit the red tape and bring relief to the many sick Gulf War veterans as quickly as the science allows," Haley said.