It would be very difficult to design a creature that is more wonderfully bizarre than the octopus. The biology of this underwater denizen is so bizarre that one could be forgiven for believing that it may have arrived from another planet entirely.
They have three hearts, one for pumping blood around the body, the other two for pumping blood by the gills. They have more neurons along their arms than they do in their heads, allowing each arm to operate independently, to the extent that they respond to stimuli even after being severed from the body. They can change their skin pattern to camouflage against their surroundings, and can eject an irritant ink when threatened by predators. Reproduction is an all around grisly affair, involving death for the male and cellular suicide for the female. They even have blue blood, as it is copper bound rather than iron bound; copper is a more efficient oxygen transporter in low temperature.
One of the most baffling aspects of octopuses is their ability to use tools and solve puzzles despite their brain structure not resembling one that would be expected to be able to produce such advanced abilities. The cerebral cortex found in humans is associated with these higher level skills. No such structure exists in octopuses, however they are the most behaviourally advanced invertebrates.
Knowing this about octopuses, it would be reasonable to assume that their lives are very different to our own. However, two academics from John Hopkins University and the University of Chicago have found a surprising similarity.
Eric Edsinger and Gül Dölen sequenced the genome of the California two-spot octopus, and found that despite being separated by 500 million years of evolution, the serotonin transporter binding site of MDMA is still conserved between humans and octopuses. Meaning that octopuses have the potential to trip on MDMA like humans do.
This is of interest in octopuses as they are significantly asocial creatures, and MDMA is a prosocial drug. On a bigger stage, there is interest in more research relating to MDMA as a therapeutic agent for conditions such as anxiety and PTSD due to its ability to reduce social anxiety and inhibition.
A behavioural study was carried out on octopuses to find out the effect of MDMA on their interactions with other octopuses. Test subjects were placed in a tank that had three chambers, one for the test subject, one with an action figure in it, and the other with another octopus in it, but under a pot with holes in it so they could see one another but not cause harm. It was found that the octopuses who had not been treated with MDMA spent the majority of their time in the chamber with the action figure, away from the other octopus. In the octopuses treated with MDMA, significantly more time was spent near the pot containing the other octopus, sometimes touching and ‘hugging’ the container.
The prosociality of the octopuses on MDMA certainly support the idea that they are affected by the drug in the same way as humans are, however this is not a definite conclusion. Serotonin is not the only neurotransmitter that MDMA can react with, so further experimentation in the future will be required to get a clearer picture of any potential mechanisms.
In the meantime, the octopuses used in the study have been retired from their duties after tripping in the name of science. The findings from the experiment were published in the journal Cell Biology.