Antidepressants at Altitude: An Animal Model

In order to investigate the higher rates of depression and suicide that have been found in people living at higher altitudes, we conducted an experiment using an animal model. We were able to simulate high and low altitude conditions using pressure chambers where rats lived for one week. Results showed that, when placed in water, female rats that lived in high altitude chambers for one week showed increased depression-like behavior as measured by behavior in response to a swimming test. Male rats did not alter their behavior with altitude.

 

Altitude Simulation Chambers: SL = sea level; 4.5K = 4,500 ft; 10K = 10,000 ft; 20K = 20,000 ft above sea level. Behavior Examined in Swimming Rats: swimming, climbing, and immobilization.

In another part of the same study, rats were given optimal doses either the SSRI fluoxetine (FLU), like Prozac, or desipramine (DES), both antidepressants, or they were given saline (C), a placebo, before participating in a swim test. After one week living in the chambers simulating high altitudes, rats living in chambers simulating altitude at 4,500 ft and 10,000 ft failed to respond to the antidepressant treatment; however, desipramine did remain effective at higher altitude. These results show that the effects of living at higher altitude lower the effectiveness of antidepressant, SSRI fluoxetine.