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Anatomy of the olfactory system and potential role for chemical communication i...
Modesto, Teresa; Gregório, Beatriz Neves; Marcelino, Gonçalo; Marquet, Nathalie; Costa, Rita; Guerreiro, Pedro Miguel; Velez, Zélia; Hubbard, PeterThe current study investigated the structure and function of the olfactory system of the Lusitanian toadfish, Halobatrachus didactylus, using histology and electrophysiology (electro-olfactogram [EOG]), respectively. The olfactory system consists of a digitated anterior peduncle, of unknown function, containing the inhalant nostril. This then leads to a U-shaped olfactory chamber with the olfactory epithelium-i...
GABA receptors in the olfactory epithelium of the gilthead seabream (Sparus aur...
Costa, Rita; Velez, Zélia; Hubbard, PeterExposure to high PCO2/low pH seawater induces behavioural alterations in fish; a possible explanation for this is a reversal of Cl-/HCO3- currents through GABAA receptors (the GABAA receptor theory). However, the main evidence for this is that gabazine, a GABAA receptor antagonist, reverses these effects when applied to the water, assuming that exposure to systems other than the CNS would be without effect. Her...
Ocean acidification affects the expression of neuroplasticity and neuromodulati...
A Costa, Rita; Olvera, Aurora; Power, Deborah Mary; Velez, ZéliaA possible explanation for acidification-induced changes in fish behaviour is that acidification interferes with neurogenesis and modifies the plasticity of neuronal circuitry in the brain. We tested the effects on the olfactory system and brain of gilthead seabream (Sparus aurata) to 4 weeks' exposure to ocean acidification (OA). Olfactory epithelium (OE) morphology changed shortly after OA exposure and persis...
A comparison of olfactory sensitivity in seawater- and freshwater-adapted bass,...
Velez, Zélia; Hubbard, Peter; Guerreiro, Pedro MiguelFish rely heavily on olfaction for many aspects of their lives including foraging, defense, migration, and reproduction. Olfactory receptor neurons in the olfactory epithelium are in direct contact with the water, and are, therefore, exposed to changes in water chemistry. The European seabass, Dicentrarchus labrax, uses estuaries as feeding grounds and migrates between seawater and brackish water; but some can ...
Independent effects of seawater pH and high P-CO2 on olfactory sensitivity in f...
Velez, Zélia; Costa, Rita; Wang, Wenjing; Hubbard, PeterOcean acidificationmay alter olfactory-driven behaviour in fish by direct effects on the peripheral olfactory system; olfactory sensitivity is reduced in CO2-acidified seawater. The current study tested whether this is due to elevated P-CO2 or the consequent reduction in seawater pH and, if the former, the possible involvement of carbonic anhydrase, the enzyme responsible for the hydration of CO2 and production...
Extracellular multi-unit recording from the olfactory nerve of teleosts
Hubbard, Peter; Velez, ZéliaRecent studies have shown that ocean acidification affects olfactory-driven behavior in fish. This may be due in part to a reduction in olfactory sensitivity in high PCO2/low pH water. To assess the effects of ocean acidification, or olfactory sensitivity in marine fish in general, we propose that extracellular multi-unit recording from the olfactory nerve is the method of choice. Although invasive, it is sensi...
Short- and medium-term exposure to ocean acidification reduces olfactory sensit...
Velez, Zélia; Roggatz, Christina C.; Benoit, David M.; Hardege, Jörg D.; Hubbard, PeterThe effects of ocean acidification on fish are only partially understood. Studies on olfaction are mostly limited to behavioral alterations of coral reef fish; studies on temperate species and/or with economic importance are scarce. The current study evaluated the effects of short- and medium-term exposure to ocean acidification on the olfactory system of gilthead seabream (Spares aurata), and attempted to expl...
Responsiveness of pituitary to galanin throughout the reproductive cycle of mal...
Pinto, P.; Velez, Zélia; Sousa, Carmen; Santos, Soraia; Andrade, André; Alvarado, M. V.; Felip, A.; Zanuy, S.; Canario, A.V.M.The neuropeptide galanin (Gal) is a putative factor regulating puberty onset and reproduction through its actions on the pituitary. The present study investigated the pituitary responsiveness to galanin and the patterns of galanin receptors (Galrs) expression throughout the reproductive cycle of two years old male European sea bass (Dicentrarchus labrax), an important aquaculture species. Quantitative analysis ...
An electrical method to measure low-frequency collective and synchronized cell ...
Medeiros, Maria C. R.; Mestre, Ana; Inácio, Pedro; Asgarif, Sanaz; Araújo, Inês M.; Hubbard, Peter C.; Velez, Zélia; Cancela, M. LeonorAn electrical method to measure extracellular bioelectrical activity in vitro is presented. This method exploits the Helmholtz capacitive double-layer established at the electrode surface. Small extracellular voltage variations in the order of μVs induce through the double-layer capacitor a displacement current that is measured. This current is then enhanced by a gain factor proportional to the electrode capaci...
Olfactory transduction pathways in the Senegalese sole Solea senegalensis
Velez, Zélia; Hubbard, Peter C.; Barata, Eduardo N.; Canário, Adelino V.M.This study tested whether differences in sensitivity between the upper and lower olfactory epithelia of Solea senegalensis are associated with different odorant receptors and transduction pathways, using the electro-olfactogram. Receptor mechanisms were assessed by cross-adaptation with amino acids (L-cysteine, L-phenylalanine and 1-methyl-L-tryptophan) and bile acids (taurocholic acid and cholic acid). This su...