Although the effect on cats was recorded over 200 years ago, it was not until the 1940s that scientists identified the constituent responsible: nepetalactone, a molecule with a structure similar to LSD. Aha! Researchers say that a “receptive” cat can sense the odour at a very low concentration in the air, on the order of one part per billion! We refer to “receptive” cats because this sensitivity is transmitted through a dominant gene. The degree of sensitivity depends on the cat’s age, environment and personality, but is sex independent. It has been noted that kittens and neutered cats react much less or not at all to the plant, and that playful and sociable cats are also more receptive.
The reaction is physiological, and usually lasts about ten minutes. It resembles the behaviour of a female cat in heat. The reaction follows a predictable sequence: the cat sniffs the plant, licks and chews the plant and shakes its head, rubs its forehead and cheeks on the plant, and then rolls on the ground with its head back. It may also stretch out its legs, scratch itself, salivate, and lick and groom itself. Researchers have tried to administer oral doses of nepetalactone to cats, but with no reaction – catnip is clearly an olfactory stimulant.
Based on an article by Édith Morin in Quatre-Temps magazine, Vol. 20, no.2.