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Show The Zebrafish Olfactory System with a Novel Transduction Pathway for Poly amines M*J, Sandersoh, ,1. k. Olsnn, l>. I*, l.ipbchit/. U. C Ylichel, Oepar Im f n t of Phys i ol ogy, 11 u i varsity f> M: ta h : low fHilyarabtr i-| i..- -I:; iSi | r.:at A deny] alt i.'rcl use To better understand the fill I extent ol Ehe odoratit detection capabilities offish, we investigated the olfactory1 sensitivity of zebruHsh to a monoamine and .several ^x>iyamineK using el ectrophy si ol ogical and ac t i v i ty de pei^ dei^ 11 abeling tecliiii ques, Electro-ol fac tog ra m record in g methods established The relative stimulatory effectiveness of these odorants as: sperm in e » spermidine > agmatine :> glutamine > putrescine = cadaverine = histamine > artificial fresh water The detection threshold for the potent poly amines was approximately 1 mM Cross-adaptation experiments suggest that each polyamine interacts with a partially-independent receptor. Three observations suggest that polyamine signaling may involve a trailsduction cascade distinct from those used by either ammo acids or bile salts. Like bile salEs and iorskolin. bttt unlike ammo acid odorants, poly am hies failed to stimulate activity-dependent labeling of olfactory sensory neurons with the cation channel perm cant probe agmatine (AGB) suggesting a signaling pathway different from that used by ami no acid stimuli. Also supporting distinct ammo acid and polyamine signaling pathways is the finding MiaE altering phospholipase C activity with Ehe inhibitor U-73J22 significantly reduced amino add-evoked responses, but had little effect on polyantine (or bile salt) evoked responses. Altering cyclic (uicleotidc- media ted signaling by adenylate cycSase activation with fomkolin, which significantly reduced responses to bile salts, failed 1o attenuate polyamine responses, suggesting that poly amines and bile salts do not share a common a transducEion cascade. Collectively, these findings suggest that poly am hies are a new class of olfactory stimuli transduced by a receptor-mediated, second messenger signaling pathway distinct from those used by ammo acids or bile salts. 47 |
