They’re often regarded as a menace, and something that wouldn’t be welcome in your garden. But now, scientists are hoping that snails can teach them a few new tricks about one of nature’s oldest secrets.
Michelle Gibson:
You may have heard in the media that some people were affected by appetite suppressants over in the United States a few years back, and they affect the serotonin levels in the body. More recently people are taking anti-anxiety medications, they’re called SSRIs. They’re serotonin modulators in the brain. These serotonin medications, while very useful, can cause heart disease in people. In snails, serotonin is a compound that they use all the time, to stimulate the heart.
Matt Smith:
So how does the snail’s heart manage to deal with serotonin?
Michelle Gibson:
That’s a very good question and that’s one of the things that we’re trying to find out, why it is that the snail seems to survive perfectly happily with high levels of serotonin in it’s system, but in humans it kills us. So this is one of the reasons I want to use this animal, because serotonin is a normal chemical mediator in the heart of a snail, and it’s something that causes disease in us.
Narration:
The heart of a snail is strangely similar to a human heart, but serotonin has little effect on it. Why is this so? Is there something that humans can learn from this? It’s these questions that Dr Michelle Gibson from La Trobe University’s school of Pharmacy and Applied Science hopes to answer.
Michelle Gibson:
If you put something like serotonin on the heart, because that stimulates the heart, you would expect these contractions to get bigger, and get closer together.
Matt Smith:
And how would that effect a human heart?
Michelle Gibson:
It would have the same effect on a human heart, it would make the heart rate go faster and the contractions get bigger, so you’d feel your heart pumping more quickly and more strongly, a bit like when you do exercise.
Michelle Gibson:
So here you can see the heart is beating regularly, nice regular amplitude, the heights are the same, nice regular frequency. Here you can see we’ve added some serotonin to the heart, and now the forces are much higher. The heart rate hasn’t changed, but certainly the forces got bigger.
Matt Smith:
So the effects of serotonin on a snails heart would be a good way to mimic the effects that serotonin would have on a human heart.
Michelle Gibson:
Absolutely. You’d want to look at the effect of the drug would have on a snail’s heart and characterise those properties, and hopefully see the same patterns you would see in something like a rat heart which would mimic a mammalian heart and a human heart. They should have the same effects, you’ll change heart rate, you’ll change the strength of contraction, the way the heart works in a snail is very similar to how it works in a human, and so we should be able to compare the results very easily.
Narration:
So far research has been encouraging, and Dr Gibson has recently presented her findings to the Australian Health and Medical Research Congress in Brisbane. In the future, the secret of how a snail copes with serotonin could have real benefits to the lives of countless people.
