AsianScientist (Mar. 15, 2021) – The cat’s finally out of the bag: it turns out that silver vine—along with the more well-known catnip—may be the feline equivalent of insect repellent. These findings were published in Science Advances.
In cats, plants like catnip are known to spark joy—spurring our furry friends to play, bounce and roll over in intense kitty bliss. In Japan, a catnip alternative known as silver vine reigns supreme, with its considerable impacts on cats depicted in traditional woodblock prints dating back to the 1800s.
Beyond inducing euphoria, however, the biological significance of such plants remain unknown. To finally resolve this long-standing mystery, researchers led by Professor Masao Miyazaki from Iwate University, along with collaborators from Nagoya University, Kyoto University and the University of Liverpool set their sights on silver vine.
The first item on their agenda? Identifying silver vine’s active ingredient. To do so, the research group isolated extracts from silver vine leaves and administered them to various cats, using a saline solution as a control. In the process, they identified a novel substance called nepetalactol that strongly triggered the characteristic cat high.
“We applied nepetalactol to laboratory paper filters and tested with eighteen laboratory and seventeen feral cats. They displayed the typical response to silver vine,” shared first author Ms. Reiko Uenoyama. “We also tested the substance with larger, non-domestic cats (jaguar, Amur leopard, and Eurasian lynx). They showed a similar reaction. We concluded nepetalactol is responsible for the typical feline reaction to silver vine.”
True enough, elevated levels of “happiness hormones” or endorphins or were found in the cats’ bloodstream after exposure to the compound. These endorphins activate the cats’ opioid systems, similar to the effects of drugs like morphine on humans.
Nepetalactol and silver vine’s benefits, however, appear to extend beyond instigating a feline frenzy. In light of recent reports showing that nepetalactone—a substance found in catnip—repels mosquitoes, Miyazaki and his colleagues hypothesized that catnip and silver vine may actually act as some form of feline insect repellent.
Putting their hypothesis to the test, the team found that less mosquitoes landed on the heads of cats with applied nepetalactol compared to those without. Likewise, mosquitoes also tended to avoid cats who were susceptible to silver vine’s effects compared to their unresponsive counterparts.
“From these results, we found that the cats’ reaction to silver vine is a chemical defense against mosquitoes, and perhaps against viruses and parasitic insects,” concluded Miyazaki.
Moving forward, the team intends to identify the feline gene responsible for silver vine’s unique effects. Their findings may also be used to develop new mosquito repellents and other similar products—indeed, the pawsibillities are endless.
Source: Iwate University; Photo: Shutterstock.
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