Author/Editor		Valentinčič, Tine; Metelko, Jutra; Ota, Damijana; Pirc, Vlado; Blejec, Andrej
Title		Olfactory discrimination of amino acids in brown bullhead catfish
Type		članek
Source		Chem Senses
Vol. and No.		Letnik 25
Publication year		2000
Volume		str. 21-9
Language		eng
Abstract		Olfactory discrimination of amino acids was investigated in brown bullhead catfish (Ameiurus nebulosus). Based on the magnitude of the observed food search activity of catfish conditioned to single amino acids, the tested compounds were classifled as being detected by the catfish as equal to, similar to, or different from the conditioned stimulus. t-Proline (L-Pro)-conditioned brown bullhead catfish discriminated all amino acids from L-Pro, but catfish conditioned to L-vallne (o-Val) and L-isoleucine (L-Ile) did not discriminate L-Val from L-Ile nor L-Ile from L-Val; however, all other amino acids tested were always discriminated from these two compounds. Catfish conditioned to L-alanine (L-Ala) discriminated basic, acidic and several neutral amino acids with long side-chains (LCNs) from t-Ala; however, they did not always discriminate r-Ala from all neutral amino acids with short side-chains (SCNs). The L-norleucine (L-nLeu)-conditioned fish responded to t-norvaline (L-nVal), L-methionine O-Met) and L-Ala similarly to L-nLeu, indicating that these amino acids are detected as similar or identical to L-nLeu. L-nLeu was, however, discriminated from L-Ala In o-Ala-conditioned catflsh. Interestingly, L-leucine (o-Leu) was discriminated from the conditioned stimuli, L-Ala, L-Ile and L-Val, indicating independent receptors for L-Leu. Although condltioned catfish dlscrimlnated other amino acids from t-arginlne hydrochloride O-Arg), In some tests they were unable to discriminate L-Arg from L-lysine hydrochloride (L-Lys). These results imply the existence of independent olfactory receptive pathways for: (i) L-Pro; (it) basic amino acids (L-Arg and L-Lys); (lil) o-Leu; (Iv) other neutral amino acids wlth branched sidechains (L-Ile and r-Vap; (v) neutral amlno acids wlth long linear side-chains O-nLeu, L-nVal and L-Met); (vi) neutral amino acids wlth short side-chains; and (vii) amino acids wlth sulfhydryl groups (L-Cys and L-homocys).
Descriptors		AMINO ACIDS DISCRIMINATION LEARNING SMELL ICTALURIDAE BEHAVIOR, ANIMAL CONDITIONING, CLASSICAL OLFACTORY PATHWAYS