A Troy University professor’s study of fish could help humans fight depression.
Dr. Julian Pittman, an associate professor in the Department of Biological and Environmental Sciences, has studied the behavior of zebrafish and found the similarities between the aquatic organisms and humans to be startling.
“When I first started in this research field, I was trying to establish an animal model for depression, which is actually quite difficult,” Pittman said. “Since we don’t have facilities for rats and mice here, I got a little creative, which is where the zebrafish came in.”
The genetic similarities between fish and humans have been studied before, but Pittman turned to the fish’s behavior in the hopes of uncovering more information about depression.
“There haven’t been a lot of studies related to that, and the studies that have been done are more related to anxiety, so I started working at the animal model,” he said. “We’ve done neurochemical studies, and they mirror the same neurotransmitters that we see fluctuate in humans. Now, it’s a great model we can test out antidepressants on and have some confidence that it may work.”
What Pittman and his team of student researchers observed was that fish who displayed depression-like symptoms floated near the bottom of their tanks, while “happy” fish stayed near the top of the tank.
Pittman’s research is shedding new light because of science’s longtime commitment to mice and rats as the primary species for medical testing.
He’s found fish to be underrated in terms of complexity.
“There’s been sort of a closed-minded view of using other species in biomedical research, because there’s so much data on rats and mice, and what people thought was ease of use because of that put blinders on them, thinking that was the only animal model to use,” he said. “I do remember when I was a child, my grandfather took me out with his friends to a lake. He said, ‘I’m going to call the fish to me and they’ll come up to feed.’ He said, ‘Here, fishy, fishy, fishy,’ and swarms of fish would come up. He’d trained them to come. I realize now they had exhibited complex behavior and the ability to learn tasks. You just don’t think of fish as being complex.”
While Pittman’s findings have been promising, he cautions that there’s still much to learn.
“It’s a great model system for high throughput testing, so what would take us years to test on rats and mice, here we’re able to test very quickly,” he said. “And if we find a lead structure compound, you could get it to marketplace a little faster. That’s definitely an advantage, but there’s still a wide gap there in knowing if we’re truly looking at depression in fish. The behavior seems to indicate the neurochemistry is there, but it’s still a bit of a black box. You wouldn’t go from zebrafish to human clinical studies. We’re not there yet.”
Still, the studies could mean a lot for the future.
“I think the holy grail is to find a medication that would be highly effective, but even more so than that, I’d like to understand depression in a more detailed way,” Pittman said. “The neurochemistry behind it is still so elusive. So many of our medications now just target serotonin, which is not the full answer, otherwise people wouldn’t still be suffering. Looking at these other neurotransmitters and how they interact with each other and elucidating that would go long way to finding better therapeutic agents.”