Octopuses given mood drug 'ecstasy' reveal genetic link to evolution of social behaviors in humans

September 20, 2018, Johns Hopkins University School of Medicine
By studying the genome of a kind of octopus not known for its friendliness toward its peers, then testing its behavioral reaction to a popular mood-altering drug called MDMA or 'ecstasy,' scientists say they have found preliminary evidence of an evolutionary link between the social behaviors of the sea creature and humans, species separated by 500 million years on the evolutionary tree. Credit: Tom Kleindinst

By studying the genome of a kind of octopus not known for its friendliness toward its peers, then testing its behavioral reaction to a popular mood-altering drug called MDMA or "ecstasy," scientists say they have found preliminary evidence of an evolutionary link between the social behaviors of the sea creature and humans, species separated by 500 million years on the evolutionary tree.

A summary of the experiments is published Sept. 20 in Current Biology, and if the findings are validated, the researchers say, they may open opportunities for accurately studying the impact of psychiatric drug therapies in many animals distantly related to people.

"The brains of are more similar to those of snails than humans, but our studies add to evidence that they can exhibit some of the same behaviors that we can," says Gül Dölen, M.D., Ph.D., assistant professor of neuroscience at the Johns Hopkins University School of Medicine and the lead investigator conducting the experiments. "What our studies suggest is that certain brain chemicals, or neurotransmitters, that send signals between neurons required for these social behaviors are evolutionarily conserved."

Octopuses, says Dölen, are well-known to be clever creatures. They can trick prey to come into their clutches, and Dölen says there is some evidence they also learn by observation and have episodic memory. The gelatinous invertebrates (animals without backbones) are further notorious for escaping from their tank, eating other animals' food, eluding caretakers and sneaking around.

But most octopuses are asocial animals and avoid others, including other octopuses. But because of some of their behaviors, Dölen still thought there may be a link between the genetics that guide social behavior in them and humans. One place to look was in the genomics that guide neurotransmitters, the signals that neurons pass between each other to communicate.

Dölen and Eric Edsinger, Ph.D., a research fellow at the Marine Biological Laboratory in Woods Hole, Massachusetts, took a closer look at the genomic sequence of Octopus bimaculoides, commonly referred to as the California two-spot octopus.

Specifically, in the gene regions that control how neurons hook neurotransmitters to their membrane, Dölen and Edsinger found that octopuses and humans had nearly identical genomic codes for the transporter that binds the neurotransmitter serotonin to the neuron's membrane. Serotonin is a well-known regulator of mood and closely linked to certain kinds of depression.

The serotonin-binding transporter is also known to be the place where the drug MDMA binds to brain cells and alters mood. So, the researchers set out to see if and/or how octopuses react to the drug, which also produces so-called pro-social behaviors in humans, mice and other vertebrates.

Dölen designed an experiment with three connected water chambers: one empty, one with a plastic action figure under a cage and one with a female or male laboratory-bred octopus under a cage.

Four male and female octopuses were exposed to MDMA by putting them into a beaker containing a liquefied version of the drug, which is absorbed by the octopuses through their gills. Then, they were placed in the experimental chambers for 30 minutes. All four tended to spend more time in the chamber where a male octopus was caged than the other two chambers.

"It's not just quantitatively more time, but qualitative. They tended to hug the cage and put their mouth parts on the cage," says Dölen. "This is very similar to how humans react to MDMA; they touch each other frequently."

Under normal conditions, without MDMA, five male and female octopuses avoided only male, caged octopuses.

Dölen says the experiments suggest that the brain circuits guiding in octopuses are present in normal conditions, but may be suppressed by natural or other circumstances. "Octopuses will suspend their antisocial for mating, for example. Then, when they are done mating, they go into aggressive, asocial mode," says Dolen.

Dölen cautions the results are preliminary and need to be replicated and affirmed in further experiments before octopuses might be used as models for brain research.

Explore further: Sex life of the blue-ringed octopus

More information: Current Biology (2018). DOI: 10.1016/j.cub.2018.07.061

Related Stories

Octopuses shed their asocial reputation

January 28, 2016

Octopuses have generally been viewed as solitary creatures—and their color-changing abilities primarily as a means to hide from hungry predators. But, after binge watching more than 52 hours of octopus TV, researchers reporting ...

New evidence suggests octupuses aren't loners

September 11, 2017

Octopuses are usually solitary creatures, but a new site in the waters off the east coast of Australia is the home of up to 15 gloomy octopuses (Octopus tetricus) that have been been observed communicating—either directly ...

Octopuses make some pretty good moves, researchers show

May 18, 2011

In case you thought that octopuses were smart only in guessing the outcome of soccer matches (remember the late Paul the octopus in Germany who picked all the right winners in last year's world cup matches in Johannesburg?), ...

Recommended for you

Scientists ID another possible threat to orcas: pink salmon

January 19, 2019

Over the years, scientists have identified dams, pollution and vessel noise as causes of the troubling decline of the Pacific Northwest's resident killer whales. Now, they may have found a new and more surprising culprit: ...

Researchers come face to face with huge great white shark

January 18, 2019

Two shark researchers who came face to face with what could be one of the largest great whites ever recorded are using their encounter as an opportunity to push for legislation that would protect sharks in Hawaii.

Why do Hydra end up with just a single head?

January 18, 2019

Often considered immortal, the freshwater Hydra can regenerate any part of its body, a trait discovered by the Geneva naturalist Abraham Trembley nearly 300 years ago. Any fragment of its body containing a few thousands cells ...

4 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Whydening Gyre
5 / 5 (6) Sep 20, 2018
Apparently, these guys were DOING MDMA when they came up with the idea to drug an octopus...
Surveillance_Egg_Unit
2 / 5 (4) Sep 20, 2018
LOL That could very well be.
They seem to be saying that under the conditions of being forced to indulge in MDMA while locked up in cages (for science), octopi will behave like humans who are also under the influence? And for that reason they plan to experiment on these innocent animals instead of on the brains of self-indulgent humans who do it voluntarily?

WHERE IS PETA? Where is the SPCA?

And yet, corals are safe from human experimentation - possibly because they aren't very mobile and don't have much of a brain - if any. Similar to El Capitan Prove-It-To-Me Prove-It-To-Me.
IwinUlose
3 / 5 (2) Sep 20, 2018
Ethical Considerations
Care of invertebrates, like O. bimaculoides, does not fall under United States Animal Welfare Act regulation, and is omitted from the PHS-NIH "Guide for the Care and Use of Laboratory Animals." Thus, an Institutional Animal Care and Use Committee, a Committee on Ethics for Animal Experiments, or other granting authority does not formally review and approve experimental procedures on and care of invertebrate species, like O. bimaculoides, at the Marine Biological Laboratory. However, in accordance with Marine Biological Laboratory Institutional Animal Care and Use Committee guidelines for invertebrates, our care and use of O. bimaculoides at the Marine Biological Laboratory and at Johns Hopkins University generally followed tenets prescribed by the Animal Welfare Act, including the three 'Rs' (refining, replacing, and reducing unnecessary animal research).


No spine? Can't whine. Esp. like the last part w/ regards to giving MDMA to octupses.
IwinUlose
3 / 5 (2) Sep 20, 2018
...Yes, they are! Quite intelligent in fact. They're known to be both curious and cautious, appear to be able to communicate with visual patterns on their skin, and even work the hardware on their cages and traverse dry environments to escape. But, well, they don't have a spine...so..

*plops octopus into MDMA solution.*
Oooh look at em go!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.