1 1 Symposium Chemosensory Receptors Satellite DEVELOPMENT ...

317 Poster Chemosensory Molecular Genetics andVNO/PheromoneINFUSIONS OF LIDOCAINE IN THE ACCESORYOLFACTORY BULB (AOB) REDUCE SEXUAL INCENTIVEMOTIVATION IN MALE RATSHurtazo H.A. 1 , Agmo A. 2 , Paredes R.G. 1 1 Instituto de Neurobiología,Universidad Nacional Autónoma de México, Querétaro, Mexico;2 Department of Psychology, University of Tromso, Tromso, NorwayOlfaction is important for the correct display of sexual behavior. Theaim of the present study was to determine if a temporary inactivation ofthe accesory olfactory bulb (AOB) inhibits sexual incentive motivationand copulatory behavior in male rats. Sexual incentive motivation wasevaluated in an arena where incentive animals (a sexually receptivefemale and a stud male) were located at diagonally opposing cornersand confined behind a wire mesh. The parameters registered were: timein and frequency of visits to an area adjacent to the incentives. Subjectswere also tested for sexual behavior with receptive females. Subjectswere tested twice before being bilaterally implanted with a guidecannulae aimed above the AOB. One week after surgery, the animalswere tested again three times in both tests. First without anymanipulation then with saline or lidocaine (1 µl of lidocaine at 10%)infused into the AOB in random order. Cannula placements wereverified using standard histological procedures. Injections of lidocaineprolonged mount and intromission latencies and reduce the time spentnear the receptive female. These results suggest that reduced preferencefor a receptive female after AOB inactivation can be explained as aconsequence of reduced incentive value of the female. Howeverdetailed studies are necessary to dissociate between reduce sexualmotivation and lack of olfactory integration. Sponsored by CONACYT28039N, DGAPA IN228199318 Poster Chemosensory Molecular Genetics andVNO/PheromoneVNO/AOB FUNCTION IN THE ABSENCE OF MOB INPUTFROM OLFACTORY EPITHELIUMSlotnick B. 1 , Restrepo D. 2 , Lin W. 2 , Sanguino A. 1 , Schellinck H. 3 ,Archbold G. 3 , Marquino G. 1 1 Psychology, University of South Florida,Tampa, FL; 2 Cellular Biology, University of Colorado, Aurora, CO;3 Psychology, Dalhousie University, Halifax, Nova Scotia, CanadaIn separate experiments with male mice we determined that: 1.Transport of HRP*WGA from OE to MOB is completely blocked for 5or more days after syringing nasal epithelium with 50 µl of 5% ZnSO 4 .This treatment had no apparent effect on anterograde transport fromVNO to AOB. 2. Treatment had little or no effect on EVOG response toliquid application of mouse urine or 2-heptanone to the VNO. 3.Application of mouse urine to the naris of awake mice induced strongFos protein expression in glomeruli as well as mitral and granule celllayers in the AOB. 4. Despite this evidence for a functional VNO/AOBsystem in the absence of OE input to the MOB, treated mice givenextensive pre-training in an olfactometer to detect the vapor of ethylacetate, methyl benzoate, mouse urine and 2-heptanone were anosmic tothese odors. 5. Nevertheless, some mice given extensive fightingexperience continued to engage in vigorous aggressive behavior aftertreatment. This is in contrast to the total absence of aggression inolfactory bulbectomized mice. Thus, in the absence of MOB activation,VNO sampling may occur in the presence of appropriate speciesspecificsocial signals but does not occur to (or does not supportdetection of) olfactometric presentations of vapors from knownpheromonal and non-pheromonal stimuli. Supported in part by NIHgrants DC04671 (BS), DC006828 (WL) and DC0056 and DC006070(DR).319 Poster Chemosensory Molecular Genetics andVNO/PheromoneVOLATILE, SEX-SPECIFIC URINARY ODORS DETECTED BYTHE MAIN OLFACTORY EPITHELIUM AUGMENT FOSEXPRESSION IN THE ACCESSORY OLFACTORY BULB OFFEMALE MICEMartel K.L. 1 , Botros J. 1 , Baum M.J. 1 1 Department of Biology, BostonUniversity, Boston, MAVolatile male urinary odorants elicit distinct patterns of glomerularactivation in the main olfactory bulb (MOB) of female mice (Schaeferet al., 2001, J. Neurosci., 21:2481-2487) whereas non-volatile bodyodorants most reliably activate the mouse accessory olfactory bulb(AOB) (Luo et al., 2003, Science, 299:1196-1201). We asked whethervolatile urinary odors from male vs female mice differentially activateMOB glomeruli as well as AOB mitral and/or granule cells of femalesubjects. Using increased Fos immunoreactivity (IR) injuxtaglomerular cells as an index of activation, we found that volatileurinary odors from male vs female mice activated distinct clusters ofglomeruli in the ventral portion of the female´s MOB. Surprisingly,exposure to volatile urinary odors from male, but not from female,conspecifics also augmented the number of Fos-IR mitral and granulecells in the female´s AOB compared with exposure only to clean air.Bilateral lesions of the main olfactory epithelium induced by ZnSO 4irrigation of the nares eliminated the ability of volatile male urinaryodors to stimulate Fos expression in the AOB and the MOB, suggestingthat the ability of volatile male odors to activate the female´s AOBnormally depends on their detection by the main olfactory epithelium asopposed to the vomeronasal organ. Our results suggest that centrifugalinputs from the main olfactory system to the AOB may selectivelyconvey information about opposite-sex conspecifics that facilitates materecognition and successful reproduction. Supported by NIH grantHD044897320 Poster Chemosensory Molecular Genetics andVNO/PheromoneRESPONSE OF OPOSSUM ACCESSORY OLFACTORY BULBNEURONS TO URINEZhang J. 1 , Huang G. 2 , Halpern M. 2 1 Anatomy and Cell Biology, SUNY,Brooklyn, NY; 2 Anatomy and Cell Biology, SUNY Downstate MedicalCenter, Brooklyn, NYIn many mammalian species, urine contains pheromones thatstimulate investigatory behaviors. Previous work in this laboratorydemonstrated that, whereas female opossums do not respond to maleopossum urine, male opossums vigorously investigate urine of diestrousfemales. In this study, we examined the response of accessory olfactorybulb (AOB) mitral cells to urine delivered to the vomeronasal organ(VNO) of male and female opossums using extracellular single unitrecordings. Mitral cells of male opossums responded to diestrous femaleurine with two distinct patterns: excitation followed by inhibition orinhibition. Either pattern could be mimicked by application of GTPgSand blocked by GDP-b-S, indicating that the response of neurons in thispathway is through a G-protein-coupled receptor mechanism. Maleurine was ineffective as a stimulus for mitral cells in the AOB of maleor female opossums. These results indicate that urine of diestrousfemales contains a pheromone (or pheromones) that directly stimulatesvomeronasal neurons through a G-protein-coupled receptor mechanismand that the response to the urine is sexually dimorphic.80