Mystical “Catnip” May 3, 2011Posted by mhostetler099 in Behavior, Biology, Chemistry, Health, Physiology.
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So what is it about “catnip” that makes cats crazy, mosquitoes fly away and at the same time has seemingly no effect on human beings? In actuality, the better question is what are the distinguishing factors allow different organisms to interpret “catnip’s” chemical signal differently or not at all.
The 6th Sense (the vomeronasal organ in cats)
It is well documented that all mammals posses 5 senses (sight, taste, touch, smell, hearing); BUT could mammals have a 6th sense?! Some scientists would say YES and pinpoint this sense to be related to the mysterious vomeronasal organ located above the roof of the mouth. This sensory organ is attributed to sensing chemical signals from other organisms and the environment known as pheromones. The vomeronasal organ is present in most mammals and is considered a chemoreceptor organ which exists as a separate entity than the nasal cavity. Chemoreceptors detect chemical signals from the organism’s environment and transduce a physiological response accordingly. Studies indicate that nepetalactone (the chemical produced by “catnip”) is responsible for eliciting a psychosexual response in cats by mimicking a sex pheromone and interacting with the feline vomeronasal organ. Although human beings and felines are both mammals, they react to the chemical in “catnip” much differently than one another. “Catnip” elicits no response in human beings and a rather strong response in felines. The distinction between these responses can most likely be attributed to a physiological difference in the feline and human sensory system.
The Vomeronasal Organ in Humans
The function of the vomeronasal organ in human beings is actually quite controversial. Studies on human embryos have indicated that the vomeronasal organ does correspond to the vomeronasal organ in cats and other mammals. Although the vomeronasal organ is common in both feline and human species, the organ in humans was thought by scientist to be vestigial (or no longer functioning). The vestigality of the vomeronasal organ in human beings may explain why humans do not react to chemicals in “catnip” however this is an unlikely explanation because studies have shown human beings can react to pheromones. Another explanation to the differing reactions could potentially be attributed to the physiological differences in the organs themselves (show left).
So Why are Mosquitoes Repelled?
So why are mosquitoes seemingly repelled by some essential oils extracted from different plants and herbs (including “catnip”)? This question is a little more difficult to answer directly because little is known about insect sensory system. Studies have shown that mosquitoes are more attracted to people with high concentrations of steroids and cholesterol on the surface of the skin. Mosquitoes are attracted and repelled by certain pheromones. More than likely, the chemical nepetalactone in “catnip” is able to mimic a pheromone that triggers a chemical signal causing the insect to become repelled (acting as an insecticide).
It is truly amazing that the same chemical can signal different responses in different organisms. The responses to chemical signals in the organism’s environment are evolutionarily beneficial; whether it be to attract a mate or flee from impending danger. According to a news report conducted by NPR the CDC is working on natural repellant consisting of extract from cedar tree. This substance is completely environmentally friendly and actually acts as an insecticide. It is able to kill the mosquitoes by blocking receptors on their nerve cells (absent in human beings). Although the chemical found in ”catnip” is not known to be an insecticide, the similarity between natural extracts (from ”catnip” and cedar tree) may certainly explain insects natural repulsion from them.
Crazy for “Catnip” March 14, 2011Posted by mhostetler099 in Behavior, Biology, Chemistry, Fun, Health, Uncategorized.
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Nepeta cataria, more commonly known as “Catnip” is a perennial herb that belongs to the mint family. This herb packs a powerful punch to cats by provoking a state of euphoria usually lasting several minutes (video). Many times herbs are utilized for medicinal purposes , but “catnip” obviously doesn’t affect human beings in the same way that it does cats. What is it about “catnip” that provokes a euphoric response in cats but not in human beings?
Studies suggests that the chemical nepetalactone found in “catnip” is primarily responsible for triggering the response in cats. Nepetalactone evokes a psychosexual response in both male and female cats by mimicking a sex pheromone found in cat urine.
Bugs aren’t so crazy for “catnip”
The chemical nepetalactone may attract felines, but does quite the opposite to some insects. Researchers at Iowa State University found that the chemical nepetalactone is a successful repellent of mosquitoes, flies, and cockroaches. Particularly, the research team at Iowa State found that a solution of catnip extract is comparable in effectiveness to a ten times more concentrated solution of DEET. Research in finding alternatives to repellents or pesticides, such as DEET, is very important because chemicals contained in most pesticides pose a serious threat to human health and the environment. Unfortunately, the essential oils in “catnip” are extremely volatile and have a potent, but short lived repelling effect. Further research in reducing its volatility is essential before such repellents can be used by the general public.
Catnip’s properties are multifunctional
Interestingly, researchers at the Max-Planck Society found that birds that used different types herbal plants in their nests produced offspring that were less prone to infestation of mites. This study indicates that other herbs may have the same insect-repelling power as “catnip” and that organisms other than humans are using this characteristic to their benefit.
In the future, the active ingredient, nepetalactone, may be found in the bottle of repellent you spray on yourself or the pesticide you sprinkle on your plants. You can be sure that the product you are using is much safer than the products of old, but if you have cats you must beware! Such products will still provoke the same euphoric response caused by “catnip” sold in pet stores.