The contribution of a Ca(2+)-activated Cl(−) conductance to amino-acid-induced inward current responses of ciliated olfactory neurons of the rainbow trout

2000 ◽  
Vol 203 (2) ◽  
pp. 253-262 ◽  
Author(s):  
K. Sato ◽  
N. Suzuki
Keyword(s):  
Rainbow Trout ◽  
Amino Acid ◽  
Reversal Potential ◽  
Amino Acid Mixture ◽  
Niflumic Acid ◽  
Flufenamic Acid ◽  
Acid Mixture ◽  
Inward Currents ◽  
Cl Channels ◽  
Cl Conductance

To determine whether amino-acid-induced inward currents of ciliated olfactory receptor neurons (ORNs) in rainbow trout (Oncorhynchus mykiss) include a Ca(2+)-activated Cl(−) conductance, we first studied changes in reversal potential and the current/voltage relationships of the responses of ORNs to an amino acid mixture (l-alanine, l-arginine, l-glutamate and l-norvaline; all 10 mmol l(−)(1)) with different concentrations of Na(+) and Cl(−) in the perfusion and recording pipette solutions. We also examined the effects of six different Cl(−) channel blockers on the responses of ORNs using a conventional whole-cell voltage-clamp technique. The amino acid mixture and one blocker were applied focally to the cilia of ORNs using a double-barrelled micropipette and a pressure ejection system. The expected shifts in reversal potential, indicating the contribution of the Ca(2+)-activated Cl(−) conductance, occurred in both positive and negative directions depending on the external and internal Na(+) and Cl(−) concentrations. Niflumic acid, flufenamic acid, NPPB [5-nitro-2-(3-phenylpropylamino)-benzonate] and DCDPC (3′, 5-dichlorodiphenylamine-2-carboxylate), at 0.5 mmol l(−)(1), reversibly blocked both the amino-acid-induced inward currents and the background activity in most ORNs. The effectiveness of these blocking agents varied from 77 to 91 % for ORNs perfused externally with standard Ringer's solution. SITS (4-acetamido-4′-isothiocyanatostilbene-2,2′-disulphonate), at 5.0 mmol l(−)(1), irreversibly inhibited the physiological response (100 % inhibition), whereas DIDS (4,4′-diisothiocyanatostilbene-2, 2′-disulphonate), at 5.0 mmol l(−)(1), had the smallest effect (45 %) of the inhibitors tested. The dose of niflumic acid inducing 50 % inhibition (IC(50)), determined specifically for the current component of the Ca(2+)-activated Cl(−) channels, was 70 μmol l(−)(1). Our results suggest that these blockers are not specific for Ca(2+)-activated Cl(−) channels and that the density of these channels varies between individual ORNs. Our results also show that the Ca(2+)-activated Cl(−) conductance plays an important role in olfactory transduction and allows fishes to adapt to various ionic environments.

scholarly journals Plasma amino acid changes in rainbow trout Salmo gairdneri force-fed casein and a corresponding amino acid mixture.

1981 ◽  
Vol 47 (8) ◽  
pp. 1035-1040 ◽  
Author(s):  
Shoji YAMADA ◽  
Kenneth L. SIMPSON ◽  
Yoshito TANAKA ◽  
Teruhisa KATAYAMA
Keyword(s):  
Rainbow Trout ◽  
Amino Acid ◽  
Amino Acid Mixture ◽  
Plasma Amino Acid ◽  
Salmo Gairdneri ◽  
Acid Mixture

An open-label, single-center pilot study to test the effects of an amino acid mixture in older patients admitted to internal medicine wards

Nutrition ◽  
2020 ◽  
Vol 69 ◽  
pp. 110588 ◽  
Author(s):  
Francesco Bellanti ◽  
Aurelio Lo Buglio ◽  
Elena Di Stasio ◽  
Giorgia di Bello ◽  
Rosanna Tamborra ◽  
...  
Keyword(s):  
Internal Medicine ◽  
Amino Acid ◽  
Pilot Study ◽  
Older Patients ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Single Center ◽  
Open Label ◽  
Internal Medicine Wards

Choosing A Balanced Amino Acid Mixture

1970 ◽  
Vol 100 (3) ◽  
pp. 380-380 ◽  
Author(s):  
Hans Fisher
Keyword(s):  
Amino Acid ◽  
Amino Acid Mixture ◽  
Acid Mixture

scholarly journals Effect of co-ingestion of amino acids with rice on glycaemic and insulinaemic response

2015 ◽  
Vol 114 (11) ◽  
pp. 1845-1851 ◽  
Author(s):  
Yean Yean Soong ◽  
Joseph Lim ◽  
Lijuan Sun ◽  
Christiani Jeyakumar Henry
Keyword(s):  
Amino Acids ◽  
Blood Glucose ◽  
Amino Acid ◽  
Glycaemic Index ◽  
Amino Acid Mixture ◽  
Postprandial Blood Glucose ◽  
Acid Mixture ◽  
White Rice ◽  
Amino Acid Mixtures

AbstractConsumption of high glycaemic index (GI) and glycaemic response (GR) food such as white rice has been implicated in the development of type 2 diabetes. Previous studies have reported the ability of individual amino acids to reduce GR of carbohydrate-rich foods. Because of the bitter flavour of amino acids, they have rarely been used to reduce GR. We now report the use of a palatable, preformed amino acid mixture in the form of essence of chicken. In all, sixteen healthy male Chinese were served 68 or 136 ml amino acid mixture together with rice, or 15 or 30 min before consumption of white rice. Postprandial blood glucose and plasma insulin concentrations were measured at fasting and every 15 min after consumption of the meal until 60 min after the consumption of the white rice. Subsequent blood samples were taken at 30-min intervals until 210 min. The co-ingestion of 68 ml of amino acid mixture with white rice produced the best results in reducing the peak blood glucose and GR of white rice without increasing the insulinaemic response. It is postulated that amino acid mixtures prime β-cell insulin secretion and peripheral tissue uptake of glucose. The use of ready-to-drink amino acid mixtures may be a useful strategy for lowering the high-GI rice diets consumed in Asia.

scholarly journals Activation of Slo2.1 channels by niflumic acid

2010 ◽  
Vol 135 (3) ◽  
pp. 275-295 ◽  
Author(s):  
Li Dai ◽  
Vivek Garg ◽  
Michael C. Sanguinetti
Keyword(s):  
Voltage Dependence ◽  
Reversal Potential ◽  
Niflumic Acid ◽  
Flufenamic Acid ◽  
Channel Activation ◽  
Outward Currents ◽  
Transmembrane Voltage ◽  
High K ◽  
Charged Residues ◽  
K Current

Slo2.1 channels conduct an outwardly rectifying K+ current when activated by high [Na+]i. Here, we show that gating of these channels can also be activated by fenamates such as niflumic acid (NFA), even in the absence of intracellular Na+. In Xenopus oocytes injected with <10 ng cRNA, heterologously expressed human Slo2.1 current was negligible, but rapidly activated by extracellular application of NFA (EC50 = 2.1 mM) or flufenamic acid (EC50 = 1.4 mM). Slo2.1 channels activated by 1 mM NFA exhibited weak voltage dependence. In high [K+]e, the conductance–voltage (G-V) relationship had a V1/2 of +95 mV and an effective valence, z, of 0.48 e. Higher concentrations of NFA shifted V1/2 to more negative potentials (EC50 = 2.1 mM) and increased the minimum value of G/Gmax (EC50 = 2.4 mM); at 6 mM NFA, Slo2.1 channel activation was voltage independent. In contrast, V1/2 of the G-V relationship was shifted to more positive potentials when [K+]e was elevated from 1 to 300 mM (EC50 = 21.2 mM). The slope conductance measured at the reversal potential exhibited the same [K+]e dependency (EC50 = 23.5 mM). Conductance was also [Na+]e dependent. Outward currents were reduced when Na+ was replaced with choline or mannitol, but unaffected by substitution with Rb+ or Li+. Neutralization of charged residues in the S1–S4 domains did not appreciably alter the voltage dependence of Slo2.1 activation. Thus, the weak voltage dependence of Slo2.1 channel activation is independent of charged residues in the S1–S4 segments. In contrast, mutation of R190 located in the adjacent S4–S5 linker to a neutral (Ala or Gln) or acidic (Glu) residue induced constitutive channel activity that was reduced by high [K+]e. Collectively, these findings indicate that Slo2.1 channel gating is modulated by [K+]e and [Na+]e, and that NFA uncouples channel activation from its modulation by transmembrane voltage and intracellular Na+.

Olfactory Conditioning by Association with Histidine-Free or Balanced Amino Acid Loads in Rats†

1973 ◽  
Vol 25 (3) ◽  
pp. 354-359 ◽  
Author(s):  
P. C. Simson ◽  
D. A. Booth
Keyword(s):  
Amino Acid ◽  
Food Intake ◽  
Amino Acid Mixture ◽  
Conditioned Aversion ◽  
Acid Mixture ◽  
Olfactory Conditioning ◽  
Conditioned Preference ◽  
Gastric Intubation ◽  
Protein Free Diet

An histidine-devoid but otherwise balanced amino acid mixture depressed food intake from 2 hr after its gastric intubation. It induced conditioned aversion to an odour incorporated in a protein-free diet presented for 6 h following intubation. In other rats, a balanced amino acid mixture established conditioned preference for odour presented in the same diet for 6 h following intubation. The degree of preference was considerably less than the degree of aversion.

Liver extract and its free amino acids equally stimulate gastric acid secretion

1980 ◽  
Vol 239 (6) ◽  
pp. G493-G496 ◽  
Author(s):  
E. J. Feldman ◽  
M. I. Grossman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Free Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Liver Extract ◽  
Amino Acid Mixture ◽  
Acid Mixture

Using intragastric titration in dogs with gastric fistulas, dose-response studies were carried out with liver extract and with a mixture of amino acids that matched the free amino acids found in liver extract. All solutions were adjusted to pH 7.0 and osmolality to 290 mosmol x kg-1. Doses are expressed as the sum of the concentrations of all free amino acids. At each dose studied (free amino acid concentration: 2.8, 5.6, 11, 23, and 45 mM), acid secretion in response to the free amino acid mixture was not significantly different from that of liver extract. The peak response to both liver extract and the free amino acid mixture occurred with the 23-mM dose and represented about 60% of the maximal response to histamine. The serum concentrations of gastrin after liver extract and the amino acid mixture were not significantly different. It is concluded that in dogs with gastric fistula, gastric acid secretion and release of gastrin were not significantly different in response to liver extract and to a mixture of amino acids that simulated the free amino acid content of liver extract.

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