title: Immunolocalization of G-protein alpha subunits in the olfactory system of the cartilaginous fish Scyliorhinus canicula.
abstract: In the olfactory and vomeronasal systems of vertebrates, the morphology of the receptor neurons, the receptor gene family they express, the G-protein coupled with the receptor (in particular the G-protein alpha subunit), and their projection to the olfactory bulb are correlated. Much information about this complicated system have been collected in different groups, but nothing is known about Chondrichthyes. In this work, the presence and distribution of immunoreactivity for different types of G-protein alpha subunit (Galpha(o), Galpha(q) and Galpha(s/olf)) were investigated in the olfactory mucosa and olfactory bulb of the shark Scyliorhinus canicula. Only Galpha(o)-like immunoreactivity was detected in the olfactory mucosa and bulb, both in tissues and homogenates. Its distribution was partially similar to that found in other vertebrates: it was localized in the microvillous receptor neurons, in numerous axon bundles of the fila olfactoria, in the stratum nervosum and in the most of glomeruli in the stratum glomerulosum. No immunoreactivity was instead observed in the crypt neurons, the second type of olfactory neurons present in cartilaginous fish. The projections of crypt neurons to olfactory bulb probably correspond to the few ventrally-located glomeruli which were negative to the antiserum against Galpha(o). These data suggest, in S. canicula, different olfactory neuron types send projections to the olfactory bulb with a segregated distribution, as observed in other vertebrates.
authors.affiliation: Department of Biology, University of Genoa, Genoa, Italy. sara.ferrando@unige.it
authors.forename: Sara
authors.initials: S
authors.lastname: Ferrando
authors.forename: Chiara
authors.initials: C
authors.lastname: Gambardella
authors.forename: Silvia
authors.initials: S
authors.lastname: Ravera
authors.forename: Sergio
authors.initials: S
authors.lastname: Bottero
authors.forename: Tiziana
authors.initials: T
authors.lastname: Ferrando
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Gallus
authors.forename: Valentina
authors.initials: V
authors.lastname: Manno
authors.forename: Amir P
authors.initials: AP
authors.lastname: Salati
authors.forename: Paola
authors.initials: P
authors.lastname: Ramoino
authors.forename: Grazia
authors.initials: G
authors.lastname: Tagliafierro
mesh_terms: D000818:Animals; D005075:Biological Evolution; D004284:Dogfish / Q000033:anatomy & histology / Q000378:metabolism*; D005260:Female; D044385:GTP-Binding Protein alpha Subunits / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D009831:Olfactory Mucosa / Q000166:cytology / Q000378:metabolism*; D009833:Olfactory Pathways / Q000166:cytology / Q000378:metabolism; D018034:Olfactory Receptor Neurons / Q000166:cytology / Q000378:metabolism*; D010802:Phylogeny; D015398:Signal Transduction / Q000502:physiology; D012903:Smell / Q000502:physiology*; D013045:Species Specificity
chemical_list: D044385:GTP-Binding Protein alpha Subunits