Researchers have found that venom from the fang blenny could be used to develop strong painkillers. This species can be found in the Great Barrier Reef at the Pacific Ocean.

The fang blenny is no bigger than 3 inches, and it has two large teeth (compared to their body size) that are filled with venom. The venom allows them to disorientate and slow down predators. The study found that the venom is packed with opioids that resemble heroin.

Fang Blenny
The study was published on March 30 in the journal Current Biology and authors believe that the findings could lead to the development of new painkillers as an alternative to opioids. Image credit: Andy Rapson.

Opioid-based painkillers are linked to addiction problems and overdose risk. Scientists still need to conduct more studies and tests of the fang blennies’ venom, but it could signify a potential breakthrough for the painkiller crisis.

Fang blennies have opioid components in their venom

The fang blennies are small fish, and researchers struggled to get the venom. The blennies only inject a small drop of poison for each bite, which was too little for a sample. The researchers dealt with the problem by taking the fishes out of their tanks and dangling cotton swabs in front of the blennies until they bit it. Afterward, they returned the fishes immediately to the reservoir, and the swabs were placed inside a solution to draw out the venom.

After they had run tests on the venom, the research team found that there were three components in it. The proteomic analysis found that the components were a neuropeptide that occurs in cone snail venom, a lipase that resembles one found in scorpions, and an opioid peptide. The researchers then conducted tests on mice, by injecting the fang blenny venom into lab mice. They were stunned when the mice showed no signs of pain.

A bluestriped fang blenny
A bluestriped fang blenny. Image credit: Wikimedia.

“For the fang blenny venom to be painless in mice was quite a surprise,” said Bryan Fry of University of Queensland and study co-author. “Fish with venomous dorsal spines produce immediate and blinding pain. The most pain I’ve ever been in other than the time I broke my back was from a stingray envenomation. ‘Sting’ray sounds so benign. They don’t sting. They are pure hell.”

The venom produces sensations of unpleasant nausea and dizziness

The venom from the fang blenny had a different effect. Because the researchers used mice for the pain test, they can’t rule out the possibility that the venom does cause pain when injected into other fish.  However, the neuropeptide and opioid components in the blennies’ venom could cause a sudden drop in blood pressure, which would not cause pain to the victim, but merely leave it disoriented and unable to chase the little fish.

Fry believes that the fang blennies use their venom to slow down their predators when they try to escape. He explains that although the feeling of pain is not produced in the victim, the opioid components from the venom can produce sensations of unpleasant nausea and dizziness in mammals.

Scientists found that other fang blennies and small fishes that aren’t venomous mimic the colors and patterns from the venomous fang blennies. To the researchers, this meant that the venom is successful.

A bluestriped fang blenny
A meiacanthus nigrolineatus, which is a poisonous fish from the family of fang blennies. Image credit: Richard Smith.

“Predatory fish will not eat those fishes because they think they are venomous and going to cause them harm, but this protection provided also allows some of these mimics to get very close to unsuspecting fish to feed on them, by picking on their scales as a micropredator,” explained Nicholas Casewell of the Liverpool School of Tropical Medicine and co-author of the study.

Casewell believes that all of the mimicking that takes place among those fishes is ultimately stimulated by the venom system that the fang blennies have. The study also found evidence that suggests that the teeth from fang blennies evolved before the venom. Casewell added that it appears as if evolution favored the little fang fish with large teeth and later by filling them with venom.

“These unassuming little fish have a really quite advanced venom system, and that venom system has a major impact on fishes and other animals in its community,” said Casewell.

Fang blennies are found near reefs, as they feed on the bottom of reef formations. Like many other species, the fang blennies are endangered because of climate change that affects the Great Barrier Reef. ] Researchers point out that species like the blennies that could help humankind are a good reason to protect the environment and to care about global warming.

Source: The University of Queensland