Sunday, July 13, 2008

Catnip -> Olfaction -> Happy

My Friend Terry Johnson is a lecturer in Bioengeneering at UC Berkeley. He also writes the Ask a Biogeek column for Now he is one of the judges for their Mad Science Contest: Build a Lifeform. And, in investigating my idea for an artificial organism, I came across this abstract:

Hart BL, Leedy MG.1985. Analysis of the catnip reaction: mediation by olfactory system, not vomeronasal organ. Behav Neural Biol. 44(1):38-46.

Pet owners and behavioral scientists alike are fascinated by unique behavioral reactions that cats show in the presence of catnip. These experiments explored the possibility that the catnip reaction might be triggered by chemosensory stimulation of the vomeronasal organ. In the chewing and mouthing of the catnip source, substances might be dissolved in saliva and transported to the vomeronasal organ. The rolling and rubbing during a catnip reaction might be a sexual response activated by the accessory olfactory system since the system projects to parts of the brain involved in mediation of sexual behavior. However, removal of the vomeronasal organ did not attenuate any of the behavioral reactions to catnip. Olfactory bulbectomy immediately eliminated catnip responding, revealing that the chemosensory stimulus evoking the catnip reaction is undoubtedly mediated through the main olfactory system. Catnip activates behavioral elements associated with several species-specific behaviors, including sniffing and chewing as associated with oral appetitive behavior, rolling and rubbing characteristic of female sexual behavior, batting the catnip source characteristic of play behavior, and a type of kicking associated with predatory behavior. These behavioral reactions occur randomly and intermittently.

The moral of the story seems to be that:
A. Cats respond to catnip through their olfaction, the type of smelling that humans do fairly well, rather than through the vomeronasal organ, the part of smelling that humans don't seem to do at all.
B. Catnip elicits from cats behaviors associated with almost every active things cats enjoy (eating, playing, sex and hunting). Catnip does not elicit the calming and resting behaviors such as self-grooming and napping that cats also enjoy. Catnip also does not elict behavior associated with things cats don't enjoy (fighting, danger, housechoirs).

Based on this, and my own observations, it seems likely that catnip is a quick-acting stimulant, extremely pleasant to the cat and absorbed through the olfactory epithelium.

Stefanie Schwartz, in her book "Psychoactive Herbs in Veterinary Medicine" list some other useful facts. Catnip response is not associated with any know histological or physiological effect, (meaning that while it certainly does something in the body, it is something subtle) catnip is not toxic even at relatively high doses, and the physiological and psychological effects are very different in cats than in humans. In humans, catnip is mild sedative, and smoked catnip is said to have similar psychtrophic effects to smoke marijiana. In cats, it is clearly a stimulant. In neither species does it have any known side effects.

Nepetalactone, the active ingredient, is also aparrently a powerful insect repellant, driving off both lice and cockroaches many times more powerfully than does DEET.

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