Mouse urine contains compounds, termed pheromones, that can alter the social or sexual behaviour of other mice. They bind to receptors a structure in the mouse nose called the vomeronasal organ. This organ is thought to be vestigial and defunct In humans, and the role of pheromones in human behavior is debated (which hasn't stopped biotec companies from selling perfumes purported to be human male or female sex attractants..... my personal trial of same did not significantly increase the rate of amorous attacks on my person from its baseline rate of zero, although I imagined that my cat might be acting a bit more affectionate). A review by Pierson (Nature 442, 495, 3 August 2006) notes "most evidence for human pheromones has come from behavioural research. In one study, scientists at the University of Chicago showed that women's menstrual cycles changed in length after they sniffed the sweat on pads previously worn in the armpits of another woman (K. Stern & M. K. McClintock Nature 392, 177–179; 1998). Another study showed that newborn babies move towards a pad carrying the smell of their mother's breast rather than a clean pad (H. Varendi & R. H. Porter Acta Paediatr. 90, 372–375; 2001).
At any rate, a report from Buck's laboratory (Nature 442, 645-650,10 August 2006) now finds mouse pheromone receptors in the lining of the nose, rather than the vomeronasal organ, and genes encoding this family of receptors are found also in humans and fish.
Figure legend: Digoxigenin-labelled antisense RNA probes for the mouse Taar genes indicated were hybridized to coronal sections of mouse olfactory epithelium. Each Taar probe hybridized to mRNA in a small percentage of OSNs scattered in selected olfactory epithelial regions. Credit: Nature Magazine
From the abstract: "these receptors, called 'trace amine-associated receptors' (TAARs), ... like odorant receptors... are expressed in unique subsets of neurons dispersed in the epithelium... at least three mouse TAARs recognize volatile amines found in urine: one detects a compound linked to stress, whereas the other two detect compounds enriched in male versus female urine—one of which is reportedly a pheromone. The evolutionary conservation of the TAAR family suggests a chemosensory function distinct from odorant receptors. Ligands identified for TAARs thus far suggest a function associated with the detection of social cues."
It remains to be seen whether activating or eliminating any of these TAAR receptors alters mouse behavior, and this needs to be demonstrated before moving on to possible human studies.
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