1 1 Symposium Chemosensory Receptors Satellite DEVELOPMENT ...

53 Poster Peripheral Olfaction and Peripheral TasteDIFFERENTIAL EXPRESSION OF NEURONAL MARKERS INOLFACTORY EPITHELIAWeiler E. 1 , Benali A. 1 1 Ruhr-University, Bochum, GermanyAll three olfactory epithelia [olfactory epithelium proper (OE), septalorgan of Masera (SO), vomeronasal organ of Jacobson (VNO)]originate from the olfactory placode. Nevertheless they exhibit somediversities. In order to characterize their neurochemical phenotypes weanalyzed their expression pattern of different neuronal marker proteinsusing immunohistochemical techniques. Olfactory bulb (OB) served asneuronal control. Neuronal Nuclei Marker (NeuN) is neither expressedin any olfactory sensory neuron, nor in relais neurons (mitral/tuftedcells) of OB. However, OB interneurons (periglomerular/granule cells)label as do supranuclear structures of VNO sustentacular cells and VNOglands. PGP9.5 (= UCHL1) expression is exact the opposite: allolfactory sensory neurons express PGP9.5 as well as OB relais neuronsbut not interneurons. Neuron specific enolase (NSE) is highestexpressed in the most apically located OE and SO neurons and patchyin VNO. In contrast, the most basally located neurons of OE and SOexpress GAP-43 cytoplasmically. In VNO neurons GAP-43 labeling isalso nuclear. OMP is cytoplasmically most intense in SO, followed byOE and least in VNO neurons; in basally located VNO neurons OMP isnuclearly localized. OB mitral cells express OMP at low levels. Theoverall epithelial expression pattern of neuronal markers reveals thatOE and SO are more similar to each other than to VNO. Within theVNO the neurons show a clear apical-basal expression diversity forneuronal markers, as they do for factors of the signal transductioncascade suggesting an involvement of those markers in the neuronalfunction. Supported by DFG Grant SFB509 TPC4 and FORUMF108/00 M122/13.54 Poster Peripheral Olfaction and Peripheral TasteSEA LAMPREY (PETROMYZON MARINUS) OLFACTORYSENSORY NEURONS DISPLAY POLYMORPHISMSLaframboise A. 1 , Chang S. 1 , Ren X. 1 , Dubuc R. 2 , Zielinski B. 11 Biological Sciences, University of Windsor, Windsor, Ontario,Canada; 2 Département de Kinanthropologie, Université du Quebec àMontréal, Montréal, Quebec, CanadaFish lack a vomeronasal organ—a spatially distinct nasalchemosensory system with microvillous sensory neurons. Rather, theirolfactory epithelium (OE) contains three types of olfactory sensoryneurons (OSNs): ciliated, microvillous and crypt. In teleost fish,ciliated OSNs express G olf , as is seen in mammalian ciliated OSNs.Less is known about the OSNs of the sea lamprey, an ancestral jawlessfish, phylogenetically removed from both mammals and teleosts.Though all lamprey OSNs are ciliated, previous work in our lab leads usto believe that they are polymorphous. In larval lamprey G olf positiveOSNs were widely distributed in the OE, while G olf negative OSNswere spatially confined and projected to a distinct area of the olfactorybulb. In the current study, we sought to identify OSN polymorphismsin the OE of the larval, transformer and adult stages of lamprey throughretrograde labelling of OSNs with biocytin and DiI, as well as G olfimmunoreactivity. We found three types of OSNs differing in G-protein expression and resembling those seen in teleosts, with somatalocated in different positions within the OE. These were 1) ciliated,with a thin dendrite and soma in the bottom region, 2) ciliated with athick axon and soma in the middle and 3) crypt-like, with soma near thetop. The crypt-like cells are mainly confined to the ventral hemisphereof the OE. More complete spatial analysis of polymorphisms in alllamprey life stages is on-going. Funding provided by GLFC andNSERC.55 Poster Peripheral Olfaction and Peripheral TasteG-PROTEINS IN THE SQUID OLFACTORY EPITHELIUMMobley A.S. 1 , Greig A. 1 , Lucero M. 1 1 Physiology, University of Utah,Salt Lake City, UTOlfactory signals from various invertebrate species are processed byat least two different G-protein mediated transduction cascades, thecAMP and IP3 pathway. In squid ORNs, physiological studies indicatethat both pathways may be present, however characterization of thetransduction molecules at the protein level is absent. Both an adenylatecyclase-like enzyme, crucial to the cAMP pathway, (Capasso et al.,1991) and two different structural and functional forms of the G-proteinGαq (Narita et al., 1999) have been shown to be present in cephalopods.Here we provide evidence that the G-proteins involved in both cAMPand IP3 pathways are present in squid ORNs (Lolliguncula brevis). Weused immunoblotting to show that Gαs/olf and Gαq are present in thesquid olfactory organ and have the same molecular weight as the mouseOE G-proteins. We also showed that both structural forms of Gαq foundby Narita et al. (1999) are present in the olfactory organ. Fixed, frozenolfactory organs were cut into 10 µm sections, double labeled for Gαqand Gαs/olf, and imaged. Three dimensional reconstructions of entireolfactory organs were analyzed for epithelial area and patterns ofimmunofluorescence. Analysis of the individual images show conservedpatterns of expression across the olfactory organ, and low co-expressionin single cells. These data suggest that the G-proteins important forcAMP and IP3 production are present in squid ORNs. Capasso et al.,(1999) Comp Biochem Physiol 100B: 805-808. Narita et al., (1999)Comp Biochem Physiol B 123: 319-327. Funded by NIH NINDS #PO1NS017938 to MTL and NIH NIDCD NRSA # 5F31DC006793-02 toASM.56 Poster Peripheral Olfaction and Peripheral TasteIMMUNOCYTOCHEMICAL LOCALIZATION OFSEROTONIN IN THE CENTRAL AND PERIPHERALCHEMOSENSORY SYSTEM OF MOSQUITOESSiju K. 1 , Hansson B. 1 , Ignell R. 1 1 SLU, Alnarp, SwedenSerotonin is a biogenic amine, which plays a crucial role in vertebrateand invertebrate nervous systems.In insects, serotonin has been shownto act as a neurotransmitter and a neuromodulator. Mosquitoes, beingblood feeding insects, mainly depend on their chemosensory system forhost-seeking and blood feeding activities.Despite the socio-economicalimportance of mosquitoes as vector species,there is a dearth ofinformation on the morphology and distribution of neurotransmittersand neuromodulators in their chemosensory system. Here,for the firsttime,we have been able to show a detailed map of serotonin-likeimmunoreactivity in the central and peripheral chemosensory system ofmosquitoes by means of immunocytochemistry. In centralchemosensory system,serotonin-like immunoreactivity was detected inthe antennal lobe(AL) as well as in the suboesophageal ganglion(SOG)and the tritocerebrum.A single centrifugal neuron was foundinnervating all AL glomeruli as well as the Johnston´s organ centre.Theaxon of this neuron projected through the Inner antennocerebral tractwith dendritic arborizations found in the calyces of mushroom body andlateral horn.In the SOG and tritocerebrum,serotonin-likeimmunoreactive fibers were found in most of the previously identifiedneuropil. In the peripheral chemosensory system,serotonin-likeimmunoreactive fibers were found in Johnston´s organ,the antennalflagellum,the maxillary palp,as well as the labium.Detection of thesefibers in peripheral system suggests the presence of a neurohemalrelease of serotonin in the periphery,which may play an important rolein the control of host-seeking and blood feeding behavior in theseinsects. Grants to BSH and RI by FORMAS14