High sensitivity of Xenopus gustatory receptors to amino acids and bitter substances

1982 ◽  
Vol 243 (1) ◽  
pp. R42-R48 ◽  
Author(s):  
K. Yoshii ◽  
C. Yoshii ◽  
Y. Kobatake ◽  
K. Kurihara
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Xenopus Laevis ◽  
High Sensitivity ◽  
Basic Amino Acid ◽  
Gustatory Receptors ◽  
Basic Amino Acids ◽  
Neutral Amino Acids ◽  
Gustatory Nerve ◽  
Cross Adaptation

The gustatory nerve responses of the aquatic toad Xenopus laevis to salts, acids, amino acids, and bitter substances were recorded. 1) The gustatory receptors were sensitive to amino acids and bitter substances. The thresholds were 10(-7) M for Arg, 3 X 10(-9) M for strychnine, and 3 X 10(-8) M for quinine, 200-20,000 times lower than the thresholds for the respective stimuli in the bullfrog. 2) The basic and the neutral amino acids were effective whereas the acidic ones were not. Relations between the responses and log stimulus concentrations for the basic amino acids were linear in a wide concentration range whereas those for the neutral ones were of S shape. Cross-adaptation did not occur among pairs of a basic amino acid and a neutral one. 3) Responses to the basic amino acids and the basic bitter substances were suppressed by the addition of salts to the stimulating solutions, while those to the neutral and the acidic substances were not suppressed.

Basic amino acid transport in renal papilla: microinfusion of Henle's loops and vasa recta

1993 ◽  
Vol 265 (6) ◽  
pp. F830-F838 ◽  
Author(s):  
W. H. Dantzler ◽  
S. Silbernagl
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Basic Amino Acid ◽  
Renal Papilla ◽  
Tubular Structures ◽  
Acid Transport ◽  
Basic Amino Acids ◽  
Neutral Amino Acids ◽  
Vasa Recta

To determine whether basic amino acids, like acidic and neutral amino acids, could be reabsorbed distal to tips of Henle's loops and recycled between loops and vasa recta in the renal papilla, we continuously microinfused ascending Henle's loops and vasa recta with 14C-labeled L-lysine (L-Lys; 1.28 mM) or L-arginine (L-Arg; 1.17 mM) and 3H-labeled inulin. We also determined percent of recovered radiolabel as intact amino acid. Like acidic and neutral amino acids, relative to inulin, approximately 30% of L-Lys and approximately 45% of L-Arg microinfused into Henle's loops were reabsorbed. However, whereas radiolabeled L-Lys reabsorption, like reabsorption of acidic and neutral amino acids, was not readily inhibited, radiolabeled L-Arg reabsorption was reduced to approximately 25% by addition of unlabled L-Arg (50 mM) or L-homoarginine (L-Homo-Arg) (50 mM) to infusate. This observation provides greater evidence for specific, carrier-mediated reabsorption for L-Arg than for acidic or neutral amino acids. About 36% (relative to inulin) of each of these amino acids microinfused into ascending vasa recta apparently was transferred directly into ipsilateral tubular structures (probably thin descending limbs of Henle's loops). Transfer of radiolabeled L-Arg was reduced to approximately 8% by the inclusion of unlabeled L-Arg (50 mM) in infusate. Transfer of unlabeled L-Lys was unaffected by inclusion of unlabeled L-Lys (50 mM) in infusate but was reduced to approximately 20% by inclusion of unlabeled L-Arg (50 mM) or L-Homo-Arg (50 mM) in infusate. (ABSTRACT TRUNCATED AT 250 WORDS)

Basic amino acid induced isomerization of a spiropyran: towards visual recognition of basic amino acids in water

2007 ◽  
Vol 31 (11) ◽  
pp. 1878 ◽  
Author(s):  
Yuanyuan Liu ◽  
Meigong Fan ◽  
Shuxiao Zhang ◽  
Xiaohai Sheng ◽  
Jiannian Yao
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Visual Recognition ◽  
Basic Amino Acid ◽  
Basic Amino Acids

Influence of organic cations on basic amino-acid uptake by human placental villi

1995 ◽  
Vol 7 (6) ◽  
pp. 1491
Author(s):  
RB Krishna ◽  
J Dancis ◽  
M Levitz
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Basic Amino Acid ◽  
Amino Acid Uptake ◽  
Progressive Increase ◽  
Amino Acid Transporters ◽  
Acid Uptake ◽  
Chorionic Villi ◽  
Basic Amino Acids ◽  
Kinetics Of

Human placental chorionic villi were incubated for 30 min with [3H]lysine or [3H]arginine and the distribution ratios (intracellular:extracellular concentrations) were determined. The ratios remained unchanged when Na+ in Earle's buffered salt solution was replaced with Li+. When Na+ was replaced with choline there was a significant increase is distribution ratios (lysine 1.34 +/- 0.33 v. 3.99 +/- 0.15, arginine 1.95 +/- 0.37 v. 5.05 +/- 1.16). Leucine, a neutral amino acid with a Na(+)-independent transport system, was unaffected by choline substitution. The distribution ratio for alanine, which is Na(+)-dependent, was reduced (2.50 +/- 0.41 v. 1.45 +/- 0.20). Two other quarternary amines, acetyl-beta-methylcholine and tetraethylammonium chloride (TEA) caused similar increases in the distribution ratios of the basic amino acids. Hordenine, a tertiary amine, was less effective and there was little or no effect with ephedrine, a secondary amine. The choline effect was first observable at concentrations of 105 mM. With TEA, there was a progressive increase in distribution ratios beginning at 29 mM. Lysine efflux was measured after incubation of villi with lysine in Earle's buffer or choline buffer. Lysine was rapidly released to the fresh medium with 25% more retained in choline-exposed villi. The amines may cause alterations in the kinetics of basic amino-acid transporters or may modify other aspects of placental physiology permitting an increase retention of the basic amino acids.

scholarly journals Gustatory responses of eel palatine receptors to amino acids and carboxylic acids.

1979 ◽  
Vol 74 (3) ◽  
pp. 301-317 ◽  
Author(s):  
K Yoshii ◽  
N Kamo ◽  
K Kurihara ◽  
Y Kobatake
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Carboxylic Acids ◽  
Carbon Chain ◽  
Threshold Concentration ◽  
The Other ◽  
Carbon Chain Length ◽  
High Concentration ◽  
Gustatory Receptors ◽  
Cross Adaptation

The gustatory receptors of the eel palate were found to be extremely sensitive to amino acids and carboxylic acids. The results obtained are as follows: (a) 11 amino acids which are among naturally occurring amino acids elicited responses in the palatine nerve, but 9 amino acids did not elicit a response even at a high concentration. The effect of D-amino acids was always much less than that of their corresponding L-isomers. There was no appreciable difference in the effectiveness of an alpha-amino acid (alpha-alanine) and beta-amino acid (beta-alanine). (b) The threshold concentrations of the most potent amino acids (arginine, glycine) were between 10(-8) and 10(-9) M. A linear relation between the magnitude of the response and log stimulus concentration held for a wide concentration range for all the amino acids examined. (c) The palatine receptors responded sensitively to various carboxylic acid solutions whose pH was adjusted to neutral. The threshold concentrations varied between 10(-4) and 10(-7) M. The magnitude of the response at 10(-2) M increased with an increase of carbon chain length. (d) The extent of cross-adaptation was examined with various combinations of amino acids. A variety of the response patterns showing complete cross-adaptation, no cross-adaptation, or synergetic interaction was observed. The synergetic interaction was also observed when one amino acid below its threshold concentration was added to the other amino acid below its threshold concentration was added to the other amino acid. No cross-adaptation was observed between amino acids and fatty acids. (e) The treatment of the palate with papain led to loss of the responses to arginine, glycine, and histidine without affecting those to proline and acetic acid. The treatment with pronase E eliminated selectively the response to proline. The possibility that the eel gustatory receptors are responsible for sensing food at a distance was discussed.

Evidence for Distinct Amino Acid Transport Systems in Cultured Tobacco Cells

1978 ◽  
Vol 33 (9-10) ◽  
pp. 641-645 ◽  
Author(s):  
Jochen Berlin ◽  
Ulrich Mutert
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Cell Lines ◽  
Amino Acid Transport ◽  
Transport Systems ◽  
Tobacco Cell ◽  
Acid Transport ◽  
Basic Amino Acids ◽  
Neutral Amino Acids

Abstract It is shown by competition experiments that tobacco cell lines have distinct transport systems for ʟ-amino acids. For all tested amino acids the Lineweaver-Burk plots were diphasic indicating the presence of more than one carrier for any one amino acid. Moreover distinct transport systems for neutral, acidic and basic amino acids were kinetically characterized. Based on competition experiments neutral amino acids were absorbed by all transport systems. Aspartic acid entered the cells via its own carrier and via the basic carrier while arginine was taken up only by the basic carrier. Neutral amino acids such as ʟ-leucine or ʟ-phenylalanine were taken up faster than acidic or basic amino acids.

Basic Amino Acids as Intracellular Cations in K Deficiency

1958 ◽  
Vol 193 (3) ◽  
pp. 644-652 ◽  
Author(s):  
Robert E. Eckel ◽  
James E. C. Norris ◽  
Charles E. Pope
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Content ◽  
Amino Acid Content ◽  
Basic Amino Acid ◽  
Basic Amino Acids ◽  
Microbiological Techniques ◽  
K Deficiency ◽  
Desoxycorticosterone Acetate

Rats were made K deficient by diet, by the injection of desoxycorticosterone acetate, and by protein repletion of protein depleted rats fed K-free diets. The tissues were examined for increases in basic amino acids. Increased amounts of l (+) lysine, identified by chromatographic, electrophoretic, enzymatic and microbiological techniques have been found in the muscle and kidney of K-deficient animals. The lysine and/or the basic amino acid content as well as the Na, K and Cl content of muscle and plasma has been measured. Lysine contributes significantly to the total cations of muscle in K deficiency. On partial K repletion, some of this lysine is apparently completely oxidized.

Atypical amino acids inhibit histidine, valine, or lysine transport into rat brain

1983 ◽  
Vol 245 (4) ◽  
pp. R556-R563 ◽  
Author(s):  
J. K. Tews ◽  
A. E. Harper
Keyword(s):  
Amino Acids ◽  
Rat Brain ◽  
Blood Brain Barrier ◽  
Brain Slices ◽  
Aromatic Amino Acids ◽  
Brain Barrier ◽  
Basic Amino Acids ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids ◽  
Single Meal

Transport of histidine, valine, or lysine into rat brain slices and across the blood-brain barrier (BBB) was determined in the presence of atypical nonprotein amino acids. Competitors of histidine and valine transport in slices were large neutral amino acids including norleucine, norvaline, alpha-aminooctanoate, beta-methylphenylalanine, and alpha-aminophenylacetate. Less effective were aromatic amino acids with ring substituents; ineffective were basic amino acids and omega-amino isomers of norleucine and aminooctanoate. Lysine transport was moderately depressed by homoarginine or ornithine plus arginine; large neutral amino acids were also similarly inhibitory. Histidine or valine transport across the BBB was also strongly inhibited by large neutral amino acids that were the most effective competitors in the slices (norvaline, norleucine, alpha-aminooctanoate, and alpha-aminophenylacetate); homoarginine and 8-aminooctanoate were ineffective. Homoarginine, ornithine, and arginine almost completely blocked lysine transport, but the large neutral amino acids were barely inhibitory. When rats were fed a single meal containing individual atypical large neutral amino acids or homoarginine, brain pools of certain large neutral amino acids or of arginine and lysine, respectively, were depleted.

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