Electrophysiological responses of Xenopus oocytes to amino acids: criteria for expression of injected mRNA coding chemoreceptors.
Responses of endogenous transporters/receptors of Xenopus oocytes to L-alanine, L-arginine, L-leucine and L-serine were investigated under voltage clamp conditions. (a) Concentration-response relations for the amino acids followed Langmuir's adsorption isotherm. (b) The neutral amino acids required Na+ to elicit the responses, whereas L-arginine did not. (c) The responses to L-alanine decreased with decreasing pH and became undetectable at pH 5.5. The present experiments supply criteria to judge if the oocytes translate exogenous mRNA coding taste or olfactory receptor proteins for the amino acids, the best characterized stimuli, especially in fishes.
Dept. of Biochemical Engineering and Science, Kyushu Institute of Technology, Fukuoka, Japan.
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Etoh
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Yoshii
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D002628:Chemoreceptor Cells; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012964:Sodium / Q000378:metabolism; D014981:Xenopus
D000596:Amino Acids; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012964:Sodium