Snails take serotonin to heart

Transcript

Narration:
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.

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