Rodents and Zebrafish
While today animal testing is becoming less popular, scientific research sometimes still uses animals to investigate the safety and effects of substances and medicines when alternatives, such as “organ-on-a-chip” models, are not suitable.
When investigating psychedelics in the lab, mice and rats are the animals most often tested on, due to their genetic similarities to humans.
So, what happens when these animals are under the influence of a psychedelic?
When a rodent has been dosed with a 5-HT2A agonist – like LSD – researchers look for a behavioural response called the “head twitch response”.
It is thought that the head twitch indicates that the substance is activating these receptors, and is a measurable indicator used to understand whether or not a compound is hallucinatory.
Rodents have also been shown to elicit responses such as acute arousal, sedation, reduced aggression, and the reversal of changes caused by chronic stress, among other effects.
Zebrafish are also a common test subject in the lab. Sharing both genetic and neurochemical similarities to humans, as well as being relatively easy to genetically manipulate, zebrafish are being utilised as pre-clinical models of hallucinations in humans.
Research shows that psychoactive substances such as LSD, MDMA, and ketamine do not change locomotive activity in zebrafish, indicating the compounds alter perception rather than movement. Additionally, LSD and MDMA have been found to reduce anxiety responses in zebrafish, similar to humans.
Some of the compounds have also been found to alter social behaviour in the fish, with these normally sociable animals reducing their shoaling behaviours, which researchers suggest could indicate an altered perception of their environment.
Octopuses and MDMA
Octopuses are highly intelligent animals and have incredibly unique biological mechanisms.
So much so that they have been described as the closest thing we currently know to an alien by Dominic Sivitilli, a graduate student in Psychology and Astrobiology at the University of Washington.
Sivitilli is interested in the biological evolution of the mind, and says that the mind of an octopus seems “worlds apart” from the human mind.
He explains that the octopus’s brain has two-thirds of its neurons living in its eight arms, and the rest in its brain. Neurons being distributed in the octopus’s arms in this way means that the arms can control themselves independently, saying that, for the octopus, this is “akin to how we use technology.”
How might then a psychoactive compound affect such a vastly different brain?
In 2018, a team from Johns Hopkins University that was researching how social behaviour evolved in animals decided to use MDMA as a tool to investigate how this impacts behaviour in octopuses.
MDMA was chosen as the compound is known to increase sociability in humans, and octopuses are typically solitary, unsociable animals.
While the brains of octopus are wildly different to ours, the researchers found that the MDMA increased the sociability of the octopus, making them more “cuddly” with each other.
Female octopuses uncharacteristically spent more time with male octopuses and were also more “qualitative” in how they spent that time, touching and feeling the cage of the male octopus. “This is very similar to how humans react to MDMA; they touch each other frequently,” said Gül Dölen, M.D., PhD, assistant professor of neuroscience at the Johns Hopkins University School of Medicine and the lead investigator conducting the experiments.
While the researchers emphasise that the findings were preliminary, the study revealed that humans and octopus share brain systems that control social connection.
Spiders and Their Intricate Webs
From orb webs, tunnel webs and sheet webs, spiders are capable of creating intricate and beautiful homes from their silk.
Looking at the house spider, a group of researchers investigated what the impacts of different drugs might be on the structure of the spider’s web.
Typically spinning the classic, flat, orbed web, the study found that when dosed with drugs such as amphetamine, LSD, chlorpromazine, diazepam, and psilocybin, for example, it impacted the size, shape, weight and design of the webs that were spun, as well as the frequency of the building.
Cannabis created webs with more gaps, and caffeine created jagged, squared shapes. LSD created “more perfect than normal” webs.
This patterned, visual evidence suggests that drugs can affect a spider’s perception of their environment.
share your toughts
Join the Conversation.