Separated by more than 500 million years of contrasting evolution, octopuses are as different from humans as any species can possibly be.
Yet, when researchers at the John Hopkins University in Baltimore, MD, exposed seven octopuses to MDMA, as part of a study, they discovered that their reaction to the drug was pretty much similar to how humans behaved when tripping on Ecstasy, Molly, Mandy, or XTC – some of the monikers that this, primarily recreational, drug is known by.
“Human and octopus lineages are separated by over 500 million years of evolution and show divergent anatomical patterns of brain organization,” wrote lead authors Gül Dölen and Eric Edsinger in the study paper published Thursday (Sep 20) in the journal Current Biology.
However, regardless of the huge differences in lineage, anatomy, and brain make-up, there is mounting evidence that point towards a common factor responsible for the social behavior exhibited across the animal kingdom, be it vertebrates like fish, birds, rodents, and primates, or invertebrates such as bees, ants, termites, and the likes.
“Despite these differences, growing evidence suggests that ancient neurotransmitter systems are shared across vertebrate and invertebrate species and in many cases enable overlapping functions,” the authors observed.
Dölen is an assistant professor of neuroscience at the John Hopkins School of Medicine’s Brain Science Institute, Wendy Klag Center, while Edsinger is a marine biologist at the Josephine Bay Paul Center, Marine Biological Laboratory, University of Chicago.
The ancient neurotransmitter systems being referred to is, therefore, the predominant factor responsible for the pro-social behavior across species, even in seemingly asocial and solitary animals like octopuses, although they are “suppressed outside the reproductive period.”
An ancient evolutionary molecule called serotonin, along with serotonin transporters – proteins responsible for moving serotonin molecules into brain cells – make up the neurotransmitter system.
So, when humans take MDMA, or whatever they like to call it, serotonin molecules bind to the serotonin transporter proteins that find their way into the brain, triggering pro-social behavior, along with a sense of well-being and euphoria; hence, the name Ecstasy.
The experiment involving seven octopuses of the Octopus bimaculoides species, also known as bimacs, suggests that octopuses are prone to similar behavior when exposed to the drug.
Under the influence of MDMA, the octopuses were friendlier and more open to physical contact with each other.
As mentioned earlier, octopuses exhibit such socially-conducive behavior when mating, which means that the neurotransmitter systems exist in the species but stay dormant outside the mating phase, or until they are given an Ecstasy fix – as the research findings indicate.
Immediately after they hatched, the seven sibling octopuses were kept together in a tank for 2-3 weeks, sharing space with hundreds of other animals, following which they were kept in social isolation for as long as seven months.
Subsequently, the animals were made to spend some time in a bath laced with MDMA, before they were moved to a tank with three sections to choose from – a central area, another with an unfamiliar male octopus in it, and a third containing “multiple configurations of 4 objects: 1) plastic orchid pot with red weight, 2) plastic bottle with green weight, 3) Galactic Heroes ‘Stormtrooper’ figurine, and 4) Galactic Heroes ‘Chewbacca’ figurine.”
Speaking to ABC, Dölen said that the initial doses were very strong and made the eight-limbed creatures super alert, instead of bringing out their suppressed pro-social side.
“I have to admit that it was totally trial and error. Honestly, I just didn’t think this was going to work, so we started out at super high doses,” she told the news channel.
“But the animals went through this hyper-vigilance where they were perched at the top of the tank like a hawk trying to watch a mouse or something.”
However, after Dölen and her team cut down on the MDMA concentration in the tank, the octopuses started exhibiting their pro-social friendlier side, spending more time with the stranger in their midst, even touching the male in a manner that exhibited curiosity rather than aggression.
Initially, when the MDMA doses were too high, the octopuses turned pale and their breathing appeared to be labored.
When the dosage was lowered, one animal was observed doing back flips; another swam around with outstretched tentacles as if doing water ballet; while a third octopus seemed particularly attracted to sounds and smells, although the evidence available is more anecdotal than scientific.
The fact that the drug-induced behavior of the octopuses was not different from how humans react when under the influence of the psychoactive drug, indicates that social behavior is entrenched in our very DNA, regardless of the divergent anatomical patterns of our brain organization.
“An octopus doesn’t have a cortex, and doesn’t have a reward circuit,” Dölen was quoted by Gizmodo as saying.
“And yet it’s able to respond to MDMA and produce the same effects, in an animal with a totally different brain organization,” she said.
“To me, that means we really need to appreciate that the business end of these things is at the level of the molecule,” she added.