Rapamycin improves learning and memory, acts as an antidepressant and elevates mood, a new study says.

The study was conducted on animal models. Mice were kept on rapamycin throughout their lifespan. Researchers found that rapamycin-fed mice had better cognitive skills.

"We made the young ones learn, and remember what they learned, better than what is normal. Among the older mice, the ones fed with a diet including rapamycin actually showed an improvement, negating the normal decline that you see in these functions with age," said Veronica Galvan, PhD, assistant professor of physiology at the Barshop Institute for Longevity and Aging Studies at the UT Health Science Center San Antonio.

Researchers say that rapamycin also lowered depression in mice. To test their depression state, researchers put these mice in a maze that had tunnels that opened to a catwalk. Mice prefer tunnels over open spaces, so any mouse exploring open space of a catwalk would be described as being more comfortable and less depressed.

Previous research has shown that rapamycin reduces seizures in mice. Rapamycin is used to prevent rejection of organ-transplant. A study published in the journal Nature says that rapamycin extends lifespan of mice.

"All of a sudden the mice are in open space. It's pretty far from the floor for their size, sort of like if a person is hiking and suddenly the trail gets steep. It's pretty far down and not so comfortable," said Jonathan Halloran also from the Barshop Institute for Longevity and Aging Studies at the UT Health Science Center San Antonio, lead author of the study.

"Mice with less anxiety were more curious to explore the catwalk. "We observed that the mice fed with a diet containing rapamycin spent significantly more time out in the open arms of the catwalk than the animals fed with a regular diet," Halloran said.

Rapamycin-fed mice were more likely to try and escape

"We found rapamycin acts like an antidepressant — it increases the time the mice are trying to get out of the situation. They don't give up; they struggle more," Dr. Galvan said.

Also, researchers found that rapamycin-fed mice had higher levels of "feel-good" neurotransmitters in the brain.

The study was published in Neuroscience.