Sleep Deprived Fish

Hello everyone, I hope you’ve all had a wonderful week. A quick update from me so I got back from skiing on Sunday and almost immediately got the flu, not a great week didn’t get out of bed Wednesday or Thursday, now I’m not good at being ill I hate not doing anything however this week I physically couldn’t do anything, so I had no choice. Anyways it’s been nice being back however I would still LOVE to be out skiing, who knows maybe one day I’ll do a ski season. So this week I’ve been reading some scientific news and I stumbled across an article about Blind Mexican Cavefish. These fish survive on very little sleep and scientists believe that if they can work out how they can survive on so little sleep they can help tweak human sleep patterns and requirements. 

 

So, the Blind Mexican Cavefish (BMC) can survive on 2 hours sleep in a 24-hour period compared to a human adult that’s 6 hours less than us. Imagine what we could do with 6 extra hours in the day it would be amazing we could be more active, spend more time with out families and loved ones, we could meal prep or take more time doing our jobs properly. Within the animal kingdom all of the animals have varying amounts of sleep requirements for example brown rats require the longest at 20 hours in a 24-hour period and a human is in the middle of the spectrum needing about 8 hours of sleep per 24 hours. Alex Keene the lead author of the paper and a neuroscientist at Florida Atlantic University has said that they can use cavefish to ask the question about why the requirements for sleep vary so much over the animal spectrum. Alex says that if they can work out how these fish can survive on so little sleep then maybe they can find ways to manipulate sleep in humans.

The species of the Mexican Cavefish has puzzled scientists for a while. It exists in two populations; the surface population lives in rivers they are more normal that the other population which lives in the caves without sunlight. The cave population have evolved this sleeplessness unlike the surface populations. Due to the absence of light the cave and surface populations have evolved to look very different, the cave dwellers have very small or no eyes completely and very little pigmentation in their bodies, both apparently involved in sleep patterns. The part that have stumped the scientists is the fact that these fish are not able to fall asleep or sleep for more than 2 hours every 24 hours and that they have 0 health consequences because of it.

In a study by the journal eLife they narrowed in on a neuropeptide called hypocretin. Now this makes sense because it is found in the hypothalamus which is the area of the brain that helps control the basics of homeostasis, like temperature, hunger and sleep. We have little to no control over these body functions, hence why hypocretin has been studied quiet a lot, especially in relation to narcolepsy, this is a sleep disorder where the person rends to fall asleep in any relaxed environment. Studies in the past have shown that dogs with narcolepsy have mutations in their hypocretin receptors, other studies have led to suggest that hypocretin is involved in the same condition for humans, and it helps regulate sleep in flies and zebrafish. In this particular study there was a comparison made between the cave dwellers and the surface dwellers to see the number of hypocretin proteins present in each. It was found that the cave dwellers had significantly more for the proteins than the fish with access to sunlight. Along with this the cave dwellers also had an increased number of receptors, for the test the researchers gave both populations of fish formulated drugs that stopped the hypocretin from attaching to the receptors. For the surface population this had hardly and affect however on the cave population it knocked them out cold. This told researchers two things unbeknownst to them before; that neural and genetic differences exist and contribute to evolution of sleep. The thoughts from this are that if a drug can be made to mimic these differences then sleep behaviours can be induced. The researchers have said that this is probably one of many genes and ways in which animals can deprive themselves of sleep without suffering ill health effects. The issue that we have it that sleep deprivation poses a large threat to our wellbeing in the long and short term some of the negative side effects can be an increase in blood pressure and inflammation, which can lead to the individual acquiring obesity, cancer, diabetes and heart disease. We have drugs that can keep up awake or make us sleep, but our bodies don’t have these specialised mechanisms that allow us not to be affected by it, Keene says that if more work can be done then a novel stimulant without negative consequences could be made.

 

I found this data from an article on Popular Science called A fish that barely sleeps could help turn humans into all-night party animals.  I found this such an interesting article to read because as I’ve said on this blog before sleep is so important and for me I often wake up not feeling refreshed and the fact that these fish can sleep for just two hours and function normally I think is incredible and the thought of having 6 extra hours in the day… well that’s just bliss. One question I’d have though it we’d be awake more when it was dark and so surely that can cause seasonal depression disorder. Anyway, that’s it for today’s blog I hope you enjoyed the slightly wacky topic I thought it was really cool and could really give s an insight into the mechanism of sleep. I’ll see you all next week remember to smile and be happy. Thank you for reading.