2009 Abstracts - Association for Chemoreception Sciences

small population of cells responding exclusively to sex-specificcues shared across strains and individuals. Female-specific cuesactivated more cells and were subject to more complex hormonalregulations than male-specific cues. In contrast to sex, strain andindividual information contained in urine was encoded by thecombinatorial activation of neurons such that urine samples fromdifferent individuals elicited distinctive patterns of activation.Interestingly, mouse urine at different concentrations activatesdistinct subsets of VNO neurons. Direct investigation of theurogenital area allows pheromones to reach the VNO at a levelthat provides unambiguous identification of the sex and the strainof animals. Lower concentration urine activates a different set ofcells, some of which are masked by high concentration urine.These observations suggest that the vomeronasal circuitry is likelyto perform complex computation of pheromone information in acontext-dependent manner to trigger innate behaviors andendocrine changes.#12 Gender effects on olfactory processingVomeronasal reception of a sex peptide pheromoneESP1 in mice: the receptor, neural circuitry, and behaviorKazushige TouharaDepartment of Integrated Biosciences, The University of TokyoChiba, JapanWe have previously discovered a male-specific putativepheromone, exocrine gland-secreting peptide 1 (ESP1), that isreleased into tear fluids from the extraorbital lacrimal gland andactivates vomeronasal sensory neurons in female mice. Here weshow the identification of a specific vomeronasal receptor V2Rp5for ESP1 and the involvement of TRPC2 in its downstream signaltransduction mechanism. The neural pathway beginning with aspecific recognition of ESP1 by V2Rp5 was visualized, showingthe transmission of the ESP1 signal to the spatially highlyorganizedpopulation of secondary neurons in the accessoryolfactory bulb. ESP1 induced a sexually dimorphic activationpattern at higher-order brain regions. We observed theinvolvement of ESP1 in a sexual behavior of female mice.Together, we demonstrate that the “labeled-line” pathwayfrom a specific receptor to the brain in a sex-specific manneris a molecular and neural basis for the vomeronasal system thatdecodes and represents information of a sex peptide pheromone.The present study provides molecular and functional linkbetween a sex peptide pheromone and a selective neuralcircuitry leading to a behavioral output via a specific receptorin the mouse vomeronasal system.10 | AChemS Abstracts 2009#13 Gender effects on olfactory processingDifferential Sensory Neuron Activation Underlies GenderDimorphic Aggressive BehaviorLisa Stowers 1 , Pablo Chamero 2 , Kelly Flanagan 1 , Fabio Papes 3 ,Darren DW Logan 1 , Toby F Marton 4 , Angeldeep Kaur 11The Scripps Research Institute La Jolla, CA, USA, 2 Universityof Saarland Homberg, Germany, 3 State University of CampinasCampinas, Brazil, 4 University of California San Diego San Diego,CA, USAFemales do not respond aggressively to the same pheromones thatprovoke aggression in males. The underlying neural code thatresults in this gender dimorphic behavior is unknown. Moleculardifferences in the sensory neurons between male and female micehave not been reported. Recent findings in Drosophila haveshown that each gender detects the ligands similarly and knowndifferences in the organization of the responsive neural circuitsmay lead to their differing innate behaviors (Datta et al., 2008).We now show that while neurons in the male vomeronasal organare activated in response to MUPs, female sensory neurons aredramatically impaired to all but one identified MUP suggestinga sensory perception difference between males and females.Interestingly, females do not robustly detect the individual MUPthat promotes aggression in males. The dimorphic sensoryresponse is not genetic but rather a response to female hormonesas juveniles of both sexes and castrated males detect all Mupssimilarly to intact males with the response extinguishing asfemales become sexually mature. This response is plastic andrapid; manipulating hormone levels in females leads to acorresponding change in the ability of vomeronasal neurons todetect and respond to Mups. The lack of response to theaggression MUP pheromone by females singularly provides anovel mechanism for this innate gender dimorphism.#14 Gender effects on olfactory processingOpposite-sex volatile urinary odors detected by the mainand processed via the accessory olfactory system contributeto mate recognition in miceMichael J. Baum 1 , Ningdong Kang 1 , Kristine M. Martel 1 ,James A. Cherry 21Dept. of Biology, Boston University Boston, MA, USA,2Dept. of Psychology, Boston University Boston, MA, USAWe assessed the contribution of main and accessory olfactorysignaling to the preference of mice to investigate opposite- versussame-sex urinary odors. Urinary volatiles from the 2 sexesstimulated distinct profiles of glomerular activation in the ventralmain olfactory bulb (MOB) of both male and female mice.By contrast, only opposite-sex urinary volatiles stimulatedFos expression in the accessory olfactory bulb (AOB) after theirdetection by the main olfactory epithelium (MOE) as opposed tothe vomeronasal organ. Tract tracing experiments in female miceshowed that urinary odors from opposite-, but not same-sex,conspecifics stimulated Fos expression in MOB mitral/tuftedcells that project directly to the ‘vomeronasal’ (medial) amygdala.Opposite-sex urinary volatiles also selectively stimulated Fosexpression in medial amygdalar neurons that send centrifugalprojections to the AOB of females. Bilateral AOB lesions in eithermale or female mice attenuated subjects’ motivation to investigateopposite-sex urinary volatiles. Opposite-sex urinary volatilesthat are initially detected by the main olfactory system gainpreferential access to the vomeronasal amygdala and theAOB with a resulting facilitation of mate recognition andreproductive success. Supported by NIH grant HD 044897.