Responses of Olfactory Forebrain Units to Amino Acids in the Channel Catfish

2007 ◽  
Vol 97 (3) ◽  
pp. 2490-2498 ◽  
Author(s):  
Alexander A. Nikonov ◽  
John Caprio
Keyword(s):  
Amino Acids ◽  
Channel Catfish ◽  
Side Chains ◽  
Single Neurons ◽  
Short Side ◽  
Biologically Relevant ◽  
Acidic Amino Acids ◽  
Group I ◽  
Group Ii ◽  
The Many

A paucity of information exists concerning the processing of odorant information by single neurons in any vertebrate above the level of the olfactory bulb (OB). In this report, odorant specificity to four types of L-α-amino acids (neutral with long side-chains, neutral with short side-chains, basic and acidic), known biologically relevant odorants for teleosts, was determined for 217 spontaneously active forebrain (FB) neurons in the channel catfish. Group I FB units were identified that were excited by only one of four types of amino acids; no Group I unit was encountered that was excited by an acidic amino acid. The Group I FB units exhibited similar preferences as described previously for OB neurons, suggesting that no major modifications of olfactory information for at least some of these units occurred between the OB and FB. Evidence, however, for the convergence of odor information between the OB and FB was suggested by Group II FB units that exhibited a broader excitatory molecular receptive range (EMRR) than those of previously recorded types of OB units or the Group I FB units. Group II FB units were excited by both neutral and basic amino acids and a few also by acidic amino acids, EMRRs not observed previously in OB units. Stimulus-induced inhibition, likely for contrast enhancement, was also often observed for the many of the FB units encountered. The observed EMRRs of the FB units presently identified and those of the OB units previously studied are consistent with the ability of catfish to behaviorally discriminate these compounds.

Facial Taste Responses of the Channel Catfish to Binary Mixtures of Amino Acids

1999 ◽  
Vol 82 (2) ◽  
pp. 564-569 ◽  
Author(s):  
K. Ogawa ◽  
J. Caprio
Keyword(s):  
Amino Acids ◽  
Binary Mixture ◽  
Binary Mixtures ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Taste Receptor ◽  
Single Fiber ◽  
Receptor Sites ◽  
Group I ◽  
Group Ii

We investigated the neural processing of binary gustatory mixtures of amino acids by the facial taste system of the channel catfish, Ictalurus punctatus. In vivo electrophysiological recordings indicated that the magnitude of both integrated and single-unit facial taste responses to binary mixtures of amino acids was greatest if the components bound to independent receptor sites. Facial taste responses were obtained from 32 multiunit and 55 single taste fiber preparations to binary mixtures of amino acids whose components bind to independent taste receptor sites (group I) or to the same or highly cross-reactive taste receptor sites (group II). All component stimuli were adjusted in concentration to provide approximately equal response magnitude as determined by either the height of the integrated multiunit taste response or by the number of action potentials generated/3 s of response time/single taste fiber. The mixture discrimination index (MDI), defined as the response to the mixture divided by the average of the responses to the component stimuli, was calculated for each test of a binary mixture. MDIs of group I binary mixtures for both the integrated multiunit and single fiber data were significantly greater than those for either the control or group II binary mixtures. In a subset of multiunit recordings, the MDIs of a group I binary mixture across three log units of stimulus concentration were similar and significantly greater than those of a group II binary mixture. Analysis of the single fiber data also indicated that the MDIs of group I binary mixtures were significantly larger than those of group II binary mixtures for both alanine-best and arginine-best taste fibers; however, the MDIs of group I binary mixtures calculated from recordings from arginine-best taste fibers were significantly greater than those recorded from alanine-best taste fibers.

scholarly journals Odorant Specificity of Single Olfactory Bulb Neurons to Amino Acids in the Channel Catfish

2004 ◽  
Vol 92 (1) ◽  
pp. 123-134 ◽  
Author(s):  
Alexander A. Nikonov ◽  
John Caprio
Keyword(s):  
Amino Acids ◽  
Olfactory Bulb ◽  
Channel Catfish ◽  
Monosodium Glutamate ◽  
Side Chains ◽  
Low Concentration ◽  
Receptor Sites ◽  
Group I ◽  
Methylene Groups ◽  
Guanidinium Group

Odorant specificity to l-α-amino acids was determined for 245 olfactory bulb (OB) neurons recorded from 121 channel catfish. The initial tests included 4 amino acids representing acidic [monosodium glutamate (Glu)], basic [arginine (Arg)], and neutral [possessing short: alanine (Ala) and long: methionine (Met) side chains] amino acids that were previously indicated to bind to independent olfactory receptor sites. Ninety-one (37%) units (Group I) tested at 1, 10, and 100 μM showed high selectivity and were excited by only one of the 4 amino acids. Odorant specificity for the vast majority of Group I units did not change over the 3 s of response time analyzed. A total of 154 OB units (63%) (Group II) were excited by a second amino acid, but only at ≥10× odorant concentration. An additional 69 Group I units were tested with related amino acids and derivatives from 10−9 to 10−5 M to determine their excitatory odorant thresholds and selectivities. Two groups of units originally selective for Met were evident: those most sensitive to neutral amino acids having branched and linear side chains, respectively. OB units originally selective for Ala responded at low concentration to other similar amino acids. Units originally selective for Arg were excited at low concentration by amino acids possessing in their side chains at least 3 methylene groups and a terminal amide or guanidinium group. The specificities of the OB units determined electrophysiologically are sufficient to account for many of the previous results of behavioral discrimination of amino acids in this and related species.

Recycling of an amino acid label with prolonged isotope infusion: implications for kinetic studies

1985 ◽  
Vol 248 (4) ◽  
pp. E482-E487 ◽  
Author(s):  
W. F. Schwenk ◽  
E. Tsalikian ◽  
B. Beaufrere ◽  
M. W. Haymond
Keyword(s):  
Amino Acids ◽  
Steady State ◽  
Amino Acid ◽  
Infusion Rate ◽  
Kinetic Studies ◽  
Intracellular Pool ◽  
Group I ◽  
Group Ii ◽  
Plasma Leucine ◽  
Amino Acid Label

To investigate whether recycling of a labeled amino acid would occur after 24 h of infusion, two groups of normal volunteers were infused with [3H]leucine and alpha-[14C]-ketoisocaproate for 4 h and [2H3]leucine for either 4 or 24 h (groups I and II, respectively). Entry of [2H3 )leucine at steady state into the plasma space was indistinguishable from its infusion rate for group I but 30% higher (P less than 0.001) than this rate for group II, demonstrating significant recycling of label. After discontinuation of the infusions, isotope disappearance from the plasma space was followed for 2 h. The 3H and 14C decay data for both groups suggest that plasma leucine and alpha-ketoisocaproate are derived from a single intracellular pool in the postabsorptive state. In group I, the 3H and 2H labels decayed identically; whereas, in group II, the decay of [2H3]-leucine and alpha-[2H3]ketoisocaproate was slower (P less than 0.01) than the decay of [3H]leucine and alpha-[3H]ketoisocaproate, confirming re-entry of label after a 24-h infusion. Therefore kinetic values calculated from models assuming no recycling of labeled amino acids are most likely not quantitative and must be interpreted with care when flux does not change or decreases.

scholarly journals Electrophysiological evidence for acidic, basic, and neutral amino acid olfactory receptor sites in the catfish.

1984 ◽  
Vol 84 (3) ◽  
pp. 403-422 ◽  
Author(s):  
J Caprio ◽  
R P Byrd
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ictalurus Punctatus ◽  
Olfactory Receptor ◽  
Olfactory Receptors ◽  
Receptor Potential ◽  
Side Chains ◽  
Short Side ◽  
Neutral Amino Acids ◽  
Receptor Sites

Electrophysiological experiments indicate that olfactory receptors of the channel catfish, Ictalurus punctatus, contain different receptor sites for the acidic (A), basic (B), and neutral amino acids; further, at least two partially interacting neutral sites exist, one for the hydrophilic neutral amino acids containing short side chains (SCN), and the second for the hydrophobic amino acids containing long side chains (LCN). The extent of cross-adaptation was determined by comparing the electro-olfactogram (EOG) responses to 20 "test" amino acids during continuous bathing of the olfactory mucosa with water only (control) to those during each of the eight "adapting" amino acid regimes. Both the adapting and test amino acids were adjusted in concentrations to provide approximately equal response magnitudes in the unadapted state. Under all eight adapting regimes, the test EOG responses were reduced from those obtained in the unadapted state, but substantial quantitative differences resulted, depending upon the molecular structure of the adapting stimulus. Analyses of the patterns of EOG responses to the test stimuli identified and characterized the respective "transduction processes," a term used to describe membrane events initiated by a particular subset of amino acid stimuli that are intricately linked to the origin of the olfactory receptor potential. Only when the stimulus compounds interact with different transduction processes are the stimuli assumed to bind to different membrane "sites." Four relatively independent L-alpha-amino acid transduction processes (and thus at least four binding sites) identified in this report include: (a) the A process for aspartic and glutamic acids; (b) the B process for arginine and lysine; (c) the SCN process for glycine, alanine, serine, glutamine, and possibly cysteine; (d) the LCN process for methionine, ethionine, valine, norvaline, leucine, norleucine, glutamic acid-gamma-methyl ester, histidine, phenylalanine, and also possibly cysteine. The specificities of these olfactory transduction processes in the catfish are similar to those for the biochemically determined receptor sites for amino acids in other species of fishes and to amino acid transport specificities in tissues of a variety of organisms.

scholarly journals ​Response of In ovo Supplementation of Amino Acid and Minerals on Egg Hatchability of Broiler Chicken

2021 ◽  
Author(s):  
M. Saravanakumar ◽  
A.V. Elangovan ◽  
V.B. Awachat ◽  
A.K. Pattanaik ◽  
A. Dhali ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Broiler Chicken ◽  
System Development ◽  
Control Group ◽  
In Ovo ◽  
Egg Hatchability ◽  
Group I ◽  
Immune System Development ◽  
Group Ii

Background: In ovo supplementation of nutrients either amino acids or minerals in broiler chicken has been common more often individually or few nutrients with positive results. In view of the above, in ovo supplementation with combination of amino acids and minerals as a complete nutrient capsule for the gut and immune system development was tested for hatchability since the modern commercial broilers are very fragile to any changes in the internal environment. Methods: Four trials were conducted to study the response of in ovo supplementation of combinations of Lys, Met, Arg, Thr, Glu, Zn, Se and Cu on hatchability of broiler eggs. In trial I, the fertile eggs on day 18 were divided into five groups of 32 eggs in each group. Group I served as control without any amino acids and mineral supplementation. Group II, III, IV and V supplemented with Lys, Met, Arg, Thr, Glu, Zn, Se and Cu @ 2.2, 1, 2.5, 1.6, 2.5 mg, 80, 0.3, 16 µg; 4.4, 2, 5, 3.2, 5 mg, 80, 0.3, 16 µg; 11, 5, 12.5, 8, 12.5 mg, 80, 0.3, 16 µg and 22, 10, 25, 16, 25 mg, 80, 0.3, 18 µg respectively. In trial II, seventy fertile eggs were divided into seven groups, Group I served as control. Group II, III, IV, V, VI and VII were supplemented with graded levels (1x to 6x) of amino acids. The 1x consisted of Lys, Met, Arg, Thr and Glu @ 2.2, 1, 2.5, 1.6 and 2.5 mg, respectively. On day 18, 10 eggs per group were supplemented with graded levels of AA combination into the amniotic fluid. In trail III and IV it was similar to trial II but was without Lys and Met, respectively. Result: Results indicated that hatchability (Trial 1) in Group V, IV, III, II and I were 0, 18, 21.8, 71 and 90.6%, respectively. The Combination of five amino acids (Trial II) (Lys, Met, Thr, Arg, Glu) for in ovo supplementation reduced the hatchability, whereas, combination of four amino acids (Trial III) (Met, Thr, Arg, Glu) without Lys at lower doses resulted in good hatchability (86.6%). In ovo supplementation of amino acid or mineral-amino acid combinations in commercial broiler eggs should be restricted to few amino acids.

Electrophysiological Evidence for a Chemotopy of Biologically Relevant Odors in the Olfactory Bulb of the Channel Catfish

2001 ◽  
Vol 86 (4) ◽  
pp. 1869-1876 ◽  
Author(s):  
Alexander A. Nikonov ◽  
John Caprio
Keyword(s):  
Amino Acids ◽  
Olfactory Bulb ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Bile Salts ◽  
Spatial Organization ◽  
Field Potential ◽  
Specific Class ◽  
Biologically Relevant ◽  
Excitatory Responses

Extracellular electrophysiological recordings from single olfactory bulb (OB) neurons in the channel catfish, Ictalurus punctatus, indicated that the OB is divided into different functional zones, each processing a specific class of biologically relevant odor. Different OB regions responded preferentially at slightly above threshold to either a mixture of 1) bile salts (10–7 to 10−5 M Na+ salts of taurocholic, lithocholic, and taurolithocholic acids), 2) nucleotides [10–6 to 10–4 M adenosine-5′-triphosphate (ATP), inosine-5′-monophosphate (IMP), and inosine-5′-triphosphate (ITP)], or 3) amino acids (10–6 to 10–4M l-alanine,l-methionine, l-arginine, andl-glutamate). Excitatory responses to bile salts were observed primarily in a thin, medial strip in both the dorsal (100–450 μm) and ventral (900–1,200 μm) OB. Excitatory responses to nucleotides were obtained primarily from dorsal, caudolateral OB, whereas excitatory responses to amino acids occurred more rostrally in the dorsolateral OB, but continued more medially in the ventral OB. The chemotopy within the channel catfish OB is more comparable to that previously described by optical imaging studies in zebrafish than by field potential studies in salmonids. The present results are consistent with recent studies, suggesting that the specific spatial organization of output neurons in the OB is necessary for the quality coding/decoding of olfactory information.

scholarly journals Hypolipemiant Actions and Possible Cardioprotective Effects of Valine and Leucine: An Experimental Study

Medicina ◽  
2021 ◽  
Vol 57 (3) ◽  
pp. 239
Author(s):  
Elena Cojocaru ◽  
Maria Magdalena Leon-Constantin ◽  
Carmen Ungureanu ◽  
Mioara Florentina Trandafirescu ◽  
Alexandra Maștaleru ◽  
...  
Keyword(s):  
Amino Acids ◽  
Experimental Study ◽  
Essential Amino Acids ◽  
Diet Group ◽  
Group Iv ◽  
Standard Diet ◽  
Novel Therapy ◽  
Group Iii ◽  
Group I ◽  
Group Ii

Background and Objectives: Considering atherosclerosis as one of the more challenging threats to healthcare worldwide, any novel therapy that counteracts the risks for developing it, provides new opportunities for the management of this process. Material and methods: We performed an experimental research in which we induced a hypercholesterolemia via a cholesterol-rich diet. Our aim was to demonstrate the antiatherogenic potential of two essential amino acids (valine and leucine). The experimental study was carried out over a period of 60 days. Male Wistar rats weighing between 250–280 g were used and divided into 4 groups, each group including 8 animals. Group I—control was fed with a standard diet. Group II received cholesterol, group III cholesterol and valine and group IV cholesterol and leucine. Blood samples were collected from the retro-orbital plexus, under anesthesia with 75 mg/kg of intraperitoneal ketamine, in three different moments (R0—1st day, R1—the 30th day, R2—the 60th day) in order to measure the levels of triglycerides. Results: In R0, there were no significant differences between the average levels of triglycerides across all the groups (p < 0.05). Compared to the group I, in R1 and R2, the average levels of triglycerides were significantly higher in all groups (p < 0.001). Also, in R1 and R2, the average triglycerides in group II receiving cholesterol (C) were significantly higher than those in group III receiving valine (C + V) as well as in group IV receiving leucine (C + L) (p < 0.001; p < 0.05). In R2, the average triglycerides in group III were significantly lower than in group IV (p < 0.001). Conclusions: Our data provides evidence that valine and leucine have a direct impact on the lipid metabolism parameters by lowering the level of triglycerides. The comparison of the two essential amino acids indicates that valine acts more promptly and rapidly than leucine.

scholarly journals Electro-olfactogram and multiunit olfactory receptor responses to complex mixtures of amino acids in the channel catfish, Ictalurus punctatus.

1991 ◽  
Vol 98 (4) ◽  
pp. 699-721 ◽  
Author(s):  
J S Kang ◽  
J Caprio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Binary Mixtures ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Olfactory Receptor ◽  
Complex Mixtures ◽  
Neutral Amino Acids ◽  
Acidic Amino Acids ◽  
Receptor Sites

In vivo electrophysiological recordings from populations of olfactory receptor neurons in the channel catfish, Ictalurus punctatus, clearly showed that both electro-olfactogram and integrated neural responses of olfactory receptor cells to complex mixtures consisting of up to 10 different amino acids were predictable with knowledge of (a) the responses to the individual components in the mixture and (b) the relative independence of the respective receptor sites for the component stimuli. All amino acid stimuli used to form the various mixtures were initially adjusted in concentration to provide approximately equal response magnitudes. Olfactory receptor responses to both multimixtures and binary mixtures were recorded. Multimixtures were formed by mixing equal aliquots of 3-10 different amino acids. Binary mixtures were formed by mixing equal aliquots of two equally stimulatory solutions. Solution 1 contained either one to nine different neutral amino acids with long side-chains (LCNs) or one to five different neutral amino acids with short side-chains (SCNs). Solution 2, comprising the binary mixture, consisted of only a single stimulus, either a LCN, SCN, basic, or acidic amino acid. The increasing magnitude of the olfactory receptor responses to mixtures consisting of an increasing number of neutral amino acids indicated that multiple receptor site types with highly overlapping specificities exist to these compounds. For both binary mixtures and multimixtures composed of neutral and basic or neutral and acidic amino acids, the receptor responses were significantly enhanced compared with those mixtures consisting of an equal number of only neutral amino acids. These results demonstrate that receptor sites for the basic and acidic amino acids, respectively, are highly independent of those for the neutral amino acids, and suggest that a mechanism for synergism is the simultaneous activation of relatively independent receptor sites by the components in the mixture. In contrast, there was no evidence for the occurrence of mixture suppression.

scholarly journals Temperature-induced phase transitions for amino acids with linear side chains

2014 ◽  
Vol 70 (a1) ◽  
pp. C170-C170
Author(s):  
Carl Henrik Görbitz ◽  
Pavel Karen ◽  
Michal Dusek ◽  
Václav Petříček
Keyword(s):  
Amino Acids ◽  
Low Temperature ◽  
Side Chain ◽  
Side Chains ◽  
Ambient Conditions ◽  
Short Side ◽  
Space Groups ◽  
Cell Parameters ◽  
Commensurate Phase ◽  
Chain Conformations

Two polymorphs are known to exist under ambient conditions for a number of amino acids (three for glycine). While investigations at high pressure have revealed a number of additional polymorphs, temperature-induced changes are rare. Low-temperature structures with modified side-chain conformations were identified for L- and DL-cysteine. Furthermore, racemates with linear side chains, such as DL-methionine and the non-standard DL-aminobutyric acid (DL-Abu), DL-aminopentanoic acid (DL-norvaline, DL-Nva) and DL-aminohexanoic acid (DL-norleucine, DL-Nle), undergo major crystalline rearrangements on transitions between P21/c and C2/c space groups [1], some of them entropy driven (disordering). As for the corresponding enantio-pure amino acids, we recently described related P21 and I2 structures at 105 K for L-Abu, both with Z' = 4 [2]. A short side-chain C–C bond (1.426 Å) in the only available CSD entry for L-Nle (at 298 K) [3] lead us to suspect that disorder could have been overlooked in the original refinement. L-Nva has not been described previously. We now present single-crystal X-ray determinations between 105 and 405 K for L-Abu, L-Nva and L-Nle, showing phase behavior of unprecedented complexity. For L-Abu and L-Nva we find three different forms in this temperature interval, while four different phases were found for L-Nle. Its known C2 structure with Z' = 1 prevails between 200 and 390 K, and the side chain is indeed disordered 2:1 over two positions. Above 390 K disorder is extensive; the space group remains C2 but cell parameters change. Upon cooling new low-temperature forms are observed at 200 and 170 K. Both are modulated, but to a different extent: data collected at 100 K reveal an almost commensurate phase, while the 180 K phase is fully incommensurate. This is, to our knowledge, the first observation of modulated structures for an amino acid, and also the first observations of major crystalline rearrangements akin to those seen for the corresponding racemates.

scholarly journals Administration of valine, leucine, and isoleucine improved plasma cholesterol and mitigated the preatherosclerotic lesions in rats fed with hypercholesterolemic diet

2018 ◽  
Vol 26 (1) ◽  
pp. 65-75
Author(s):  
Simona Ifrim ◽  
Cornelia Amalinei ◽  
Elena Cojocaru ◽  
Mioara Calipsoana Matei
Keyword(s):  
Amino Acids ◽  
Plasma Cholesterol ◽  
Serum Levels ◽  
Essential Amino Acids ◽  
Diet Group ◽  
Standard Diet ◽  
Internal Elastic Lamina ◽  
Group I ◽  
Male Wistar Rats ◽  
Group Ii

Abstract Hypercholesterolemia has a major contribution to the occurrence and progression of atherosclerotic lesions. Recent studies report the involvement of branched-chain amino acids in cholesterol methabolism. The aim of this research was to evaluate the role of valine, leucine and isoleucine on the occurrence and progression of atherosclerosis in rats receiving hypercholesterolic diet. Material and methods: 50 male Wistar rats distributed into five groups with the following type of diets: group I (control) received standard diet; group II - cholesterol; group III - cholesterol and valine; group IV - cholesterol and leucine; group V - cholesterol and isoleucine. The experimental study was conducted over a period of 2 months. The animals were evaluated for the serum levels of total cholesterol at the beginning of the experiment, after 1 month and after 2 months. The collected tissue fragments of heart and aorta were prepared for the examination by optical microscopy in order to identify the atherosclerotic changes. Results: The most increased values of serum cholesterol were recorded in rats from group II (p=0.001), for the second and third evaluation. The histological examination showed early histopathological lesions on the vascular intima for the groups treated with cholesterol, valine, leucine, and isoleucine. These early changes (the occurrence of some superficial endothelial erosions, adhesion of erythrocytes and platelets) were correlated with the degree of the arterial wall damage, of the leukocytes adhesion to the arterial intima, and the discontinuities of the internal elastic lamina. Conclusion: The comparative study of the effects of the three essential amino acids revealed that valine induced a faster response than leucine and isoleucine on the improvement of biochemical parameters, but there were no significant differences between the three amino acids in terms of their protective ability, demonstrated by the histopathological lesion assessment.

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