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BACKGROUND: To date, no studies have directly compared the differences between presleep and daytime protein (PRO) consumption on localized and systemic fat metabolism in active women. OBJECTIVE: The purpose of this study was to assess the effects of presleep compared with daytime PRO supplementation on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and whole-body substrate utilization in women. METHODS: Thirteen young (mean ± SE age: 22 ± 1 y; BMI: 24.3 ± 0.8 kg/m2), resistance-trained [1 repetition maximum (1RM) squat percentage of body weight: 135% ± 6%; 1RM bench press percentage of body weight: 82% ± 4%] women volunteered. On overnight experimental visits, participants performed full-body resistance exercise (RE; 65% 1RM) and were randomly assigned to consume either daytime PRO (PRO, 30 g casein) 30 min post-RE and presleep (30 min before bed) noncaloric, sensory-matched placebo (PLA, 0 g casein) (PRO-PLA), or the opposite (PLA-PRO), switching the order of the supplements on the following visit. SCAAT lipolysis, resting metabolism (indirect calorimetry), and plasma biomarkers (glucose, insulin, nonesterified fatty acids, glycerol) were measured at baseline, overnight, and the next morning. RESULTS: There were no differences in overnight SCAAT lipolysis between conditions indicated by interstitial glycerol concentrations (PRO-PLA: baseline, 669 ± 137; next morning, 321 ± 77.1; PLA-PRO: baseline, 524 ± 109; next morning, 333 ± 68.0 µM), fat oxidation (PRO-PLA: baseline, 5.70 ± 0.35; next morning, 5.00 ± 0.28; PLA-PRO: baseline, 6.59 ± 0.32; next morning, 5.44 ± 0.27 g/min), or any other measure. CONCLUSIONS: There was no difference between the effects of daytime and presleep PRO supplementation on SCAAT lipolysis or whole-body substrate utilization in resistance-trained women. Presleep PRO is a viable option for increasing PRO consumption in resistance-trained women because it does not blunt overnight lipolysis, and will therefore likely not lead to increases in subcutaneous abdominal fat.This trial was registered at clinicaltrials.gov as NCT03573687.
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Caseínas/administração & dosagem , Fenômenos Cronobiológicos/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipólise , Treinamento Resistido , Sono , Caseínas/metabolismo , Fenômenos Cronobiológicos/fisiologia , Estudos Cross-Over , Proteínas Alimentares , Método Duplo-Cego , Metabolismo Energético , Feminino , Humanos , Oxirredução , Adulto JovemRESUMO
In nature, water is present as a low-salt solution, thus we hypothesized that thirst would increase taste responses to low-salt solutions. We investigated the effect of thirst on the 2 different salt detection mechanisms present in the rat chorda tympani (CT) nerve. The first mechanism is dependent upon the epithelial sodium channel (ENaC), is blocked by benzamil, and is specific to the cation sodium. The second mechanism, while undefined, is independent of ENaC, and detects multiple cations. We expected thirst to increase benzamil-sensitive sodium responses due to mechanistically increasing the benzamil-sensitive ENaC. We recorded CT whole-nerve electrophysiological responses to lingual application of NaCl, KCl (30, 75, 150, 300, 500, and 600 mM), and imitation rainwater in both control and 24-h water-restricted male rats. NaCl solutions were presented in artificial saliva before and after lingual application of 5µM benzamil. Water restriction significantly increased the integrated CT responses to NaCl but not to KCl or imitation rainwater. Consistent with our hypothesis, only the benzamil-sensitive, and not the benzamil-insensitive, CT sodium response significantly increased. Additionally, CT responses to salt were recorded following induction of either osmotic or volemic thirst. Both thirsts significantly enhanced the integrated CT responses to NaCl and KCl, but not imitation rainwater. Interestingly, osmotic and volemic thirsts increased CT responses by increasing both the benzamil-sensitive and benzamil-insensitive CT sodium responses. We propose that thirst increases the sensitivity of the CT nerve to sodium.
Assuntos
Nervo da Corda do Tímpano/efeitos dos fármacos , Nervo da Corda do Tímpano/fisiologia , Canais Epiteliais de Sódio/metabolismo , Cloreto de Sódio/farmacologia , Sede/fisiologia , Amilorida/análogos & derivados , Amilorida/farmacologia , Animais , Bloqueadores do Canal de Sódio Epitelial/farmacologia , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Temperature profoundly affects the perceived intensity of taste, yet we know little of the extent of temperature's effect on taste in the peripheral nervous system. Accordingly, we investigated the influence of temperature from 23 °C to 43 °C in 4 °C intervals on the integrated responses of the chorda tympani (CT) nerve to a large series of chemical stimuli representing sweet, salty, sour, bitter, and umami tastes in C57BL/J6 mice. We also measured neural responses to NaCl, Na-gluconate, Na-acetate, Na-sulfate, and MSG with and without 5 µM benzamil, an epithelial sodium channel (ENaC) antagonist, to assess the influence of temperature on ENaC-dependent and ENaC-independent response components. Our results showed that for most stimuli (0.5M sucrose, glucose, fructose, and maltose; 0.02M saccharin and sucralose; 0.5M NaCl, Na-gluconate, Na-acetate, Na-sulfate, KCl, K-gluconate, K-acetate, and K-sulfate; 0.05M citric acid, acetic acid, and HCl; 0.1M MSG and 0.05M quinine hydrochloride: QHCl), CT response magnitudes were maximal between 35 °C and 39 °C and progressively smaller at cooler or warmer temperatures. In contrast, the weakest responses to NH 4 Cl, (NH 4 ) 2 SO4, and K-sulfate were at the lowest temperature, with response magnitude increasing monotonically with increasing temperature, while the largest responses to acetic acid were at the lowest temperature, with response magnitude decreasing with increasing temperature. The response to sweet and umami stimuli across temperatures were similar reflecting the involvement of TRPM5 activity, in contrast to bitter stimuli, which were weakly affected by temperature. Temperature-modulated responses to salts and acids most likely operate through mechanisms independent of ENaC and TRPM5.
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OBJECTIVE: To compare measures of training, performance, body composition, and areal bone mineral density (aBMD) between age-matched recreational and competitively trained male road cyclists. DESIGN: Cross-sectional. SETTING: Laboratory. PARTICIPANTS: Male cyclists (N = 28) aged 21-54 years riding more than 3 hours per week. ASSESSMENT OF RISK FACTORS: Men who train at high (≥8 h/wk) and moderate volumes (3-8 h/wk). MAIN OUTCOME MEASURES: Areal bone mineral density assessments by dual energy x-ray absorptiometry of the whole body, lumbar spine (L1-L4), right and left hips, maximal oxygen uptake (V[Combining Dot Above]O2max), and training history. RESULTS: Trained cyclists had higher power to weight (5.3 ± 0.4 vs 4.7 ± 0.3 W/kg, P = 0.001), V[Combining Dot Above]O2max (57.2 ± 4.5 vs 53.0 ± 6.1 mL·kg·min, P = 0.049) and training volume (10.6 ± 2.1 vs 6.3 ± 0.9 h/wk, P < 0.001) than recreational cyclists. Trained cyclists had lower right (0.898 ± 0.090 vs 0.979 ± 0.107 g/cm, P = 0.047) and left hip aBMD (0.891 ± 0.079 vs 0.973 ± 0.104 g/cm, P = 0.032). Z-scores identified lumbar (L1-L4) aBMD as osteopenic (-2.5 < Z-score < -1.0) in trained cyclists (-1.39 ± 1.09). Lumbar scans identified 12 trained and 4 recreational cyclists as osteopenic and 3 trained cyclists as osteoporotic. CONCLUSIONS: Areal bone mineral density is lower in trained male road cyclists compared with recreational, specifically at the hips. Lumbar aBMD is low in both trained and recreational cyclists. Research is needed to determine the chronic effects of cycling on aBMD and interventions that improve aBMD in this population. CLINICAL RELEVANCE: This study suggests road cycling may compromise aBMD and potentially increase the likelihood of low-trauma fractures; health care professionals should consider this exposure when exercise prescriptions are designed for patients at-risk for osteopenia/osteoporosis, for example, women and older adults.
Assuntos
Atletas/estatística & dados numéricos , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Densidade Óssea , Adulto , Estudos Transversais , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
The primary aim of this study was to compare 2 daily undulating periodization (DUP) models on one-repetition maximum (1RM) strength in the squat, bench press, deadlift, total volume (TV) lifted, and temporal hormone response. Eighteen male, college-aged (21.1 ± 1.9 years) powerlifters participated in this study and were assigned to one of 2 groups: (a) traditional DUP training with a weekly training order: hypertrophy-specific, strength-specific, and power-specific training (HSP, n = 9) or (b) modified DUP training with a weekly training order: hypertrophy-specific, power-specific, and strength-specific training (HPS, n = 9). Both groups trained 3 nonconsecutive days per week for 6 weeks and performed the squat, bench press, and deadlift exercises. During hypertrophy and power sessions, subjects performed a fixed number of sets and repetitions but performed repetitions until failure at a given percentage during strength sessions to compare TV. Testosterone and cortisol were measured at pretesting and posttesting and before each strength-specific day. Hypertrophy, power, and strength produced greater TV in squat and bench press (p ≤ 0.05) than HSP, but not for deadlift (p > 0.05). For squat and deadlift, there was no difference between groups for 1RM (p > 0.05); however, HPS exhibited greater increases in 1RM bench press than HSP (p ≤ 0.05). Effect sizes (ES) showed meaningful differences (ES > 0.50) in favor of HPS for squat and bench press 1RM. Testosterone decreased (p ≤ 0.05) at weeks 5 and 6 and cortisol decline at weeks 3 and 4. However, neither hormone was different at posttesting compared with pretesting (p > 0.05). Our findings suggest that an HPS configuration of DUP has enhanced performance benefits compared with HSP.
Assuntos
Força Muscular , Treinamento Resistido/métodos , Levantamento de Peso/fisiologia , Adulto , Teste de Esforço , Humanos , Hidrocortisona/sangue , Masculino , Modelos Biológicos , Testosterona/sangue , Adulto JovemRESUMO
The purpose of this study was to investigate the influence of anion size and the contribution of the epithelial sodium channel (ENaC) and the transient receptor potential vanilloid-1 (TRPV1) channel on sodium-taste responses in rat chorda tympani (CT) neurons. We recorded multiunit responses from the severed CT nerve and single-cell responses from intact, narrowly tuned and broadly tuned, salt-sensitive neurons in the geniculate ganglion simultaneously with stimulus-evoked summated potentials to signal when the stimulus contacted the lingual epithelium. Artificial saliva served as the rinse and solvent for all stimuli (0.3 M NH(4)Cl, 0.5 M sucrose, 0.03-0.5 M NaCl, 0.01 M citric acid, 0.02 M quinine hydrochloride, 0.1 M KCl, and 0.03-0.5 M Na-gluconate). We used the pharmacological antagonist benzamil to assess NaCl responses mediated by ENaC, and SB-366791 and cetylpyridinium chloride to assess responses mediated by TRPV1. CT nerve responses were greater to NaCl than Na-gluconate at each concentration; this was attributed mostly to broadly tuned, acid-generalist neurons that responded with higher frequency and shorter latency to NaCl than Na-gluconate. In contrast, narrowly tuned NaCl-specialist neurons responded more similarly to the two salts, but with subtle differences in temporal pattern. Benzamil reduced CT nerve and single-cell responses only of narrowly tuned neurons to NaCl. Surprisingly, SB-366791 and cetylpyridinium chloride were without effect on CT nerve or single-cell NaCl responses. Collectively, our data demonstrate the critical role that apical ENaCs in fungiform papillae play in processing information about sodium by peripheral gustatory neurons; the role of TRPV1 channels is an enigma.
Assuntos
Nervo da Corda do Tímpano/fisiologia , Cloreto de Sódio/farmacologia , Paladar/fisiologia , Animais , Nervo da Corda do Tímpano/efeitos dos fármacos , Canais Epiteliais de Sódio/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Canais de Cátion TRPV/metabolismo , Paladar/efeitos dos fármacos , Percepção Gustatória/efeitos dos fármacos , Percepção Gustatória/fisiologia , Língua/efeitos dos fármacos , Língua/inervação , Língua/metabolismoRESUMO
Sour and salt taste interactions are not well understood in the peripheral gustatory system. Therefore, we investigated the interaction of acetic acid and NaCl on taste processing by rat chorda tympani neurons. We recorded multi-unit responses from the severed chorda tympani nerve (CT) and single-cell responses from intact narrowly tuned and broadly tuned salt-sensitive neurons in the geniculate ganglion simultaneously with stimulus-evoked summated potentials to signal when the stimulus contacted the lingual epithelium. Artificial saliva served as the rinse and solvent for all stimuli [0.3 M NH(4)Cl, 0.5 M sucrose, 0.1 M NaCl, 0.01 M citric acid, 0.02 M quinine hydrochloride (QHCl), 0.1 M KCl, 0.003-0.1 M acetic acid, and 0.003-0.1 M acetic acid mixed with 0.1 M NaCl]. We used benzamil to assess NaCl responses mediated by the epithelial sodium channel (ENaC). The CT nerve responses to acetic acid/NaCl mixtures were less than those predicted by summing the component responses. Single-unit analyses revealed that acetic acid activated acid-generalist neurons exclusively in a concentration-dependent manner: increasing acid concentration increased response frequency and decreased response latency in a parallel fashion. Acetic acid suppressed NaCl responses in ENaC-dependent NaCl-specialist neurons, whereas acetic acid-NaCl mixtures were additive in acid-generalist neurons. These data suggest that acetic acid attenuates sodium responses in ENaC-expressing-taste cells in contact with NaCl-specialist neurons, whereas acetic acid-NaCl mixtures activate distinct receptor/cellular mechanisms on taste cells in contact with acid-generalist neurons. We speculate that NaCl-specialist neurons are in contact with type I cells, whereas acid-generalist neurons are in contact with type III cells in fungiform taste buds.
Assuntos
Ácido Acético/farmacologia , Nervo da Corda do Tímpano/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Tempo de Reação , Papilas Gustativas/fisiologia , Animais , Canais Epiteliais de Sódio , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Masculino , Ratos , Ratos Sprague-Dawley , Cloreto de Sódio/farmacologia , Paladar/fisiologiaRESUMO
In rodents, at least two transduction mechanisms are involved in salt taste: 1) the sodium-selective epithelial sodium channel, blocked by topical amiloride administration, and 2) one or more amiloride-insensitive cation-nonselective pathways. Whereas electrophysiological evidence from the chorda tympani nerve (CT) has implicated the transient receptor potential vanilloid-1 (TRPV1) channel as a major component of amiloride-insensitive salt taste transduction, behavioral results have provided only equivocal support. Using a brief-access taste test, we examined generalization profiles of water-deprived C57BL/6J (WT) and TRPV1 knockout (KO) mice conditioned (via LiCl injection) to avoid 100 µM amiloride-prepared 0.25 M NaCl and tested with 0.25 M NaCl, sodium gluconate, KCl, NH(4)Cl, 6.625 mM citric acid, 0.15 mM quinine, and 0.5 M sucrose. Both LiCl-injected WT and TRPV1 KO groups learned to avoid NaCl+amiloride relative to controls, but their generalization profiles did not differ; LiCl-injected mice avoided the nonsodium salts and quinine suggesting that a TRPV1-independent pathway contributes to the taste quality of the amiloride-insensitive portion of the NaCl signal. Repeating the experiment but doubling all stimulus concentrations revealed a difference in generalization profiles between genotypes. While both LiCl-injected groups avoided the nonsodium salts and quinine, only WT mice avoided the sodium salts and citric acid. CT responses to these stimuli and a concentration series of NaCl and KCl with and without amiloride did not differ between genotypes. Thus, in our study, TRPV1 did not appear to contribute to sodium salt perception based on gustatory signals, at least in the CT, but may have contributed to the oral somatosensory features of sodium.
Assuntos
Nervo da Corda do Tímpano/fisiologia , Cloreto de Sódio/farmacologia , Canais de Cátion TRPV/metabolismo , Paladar , Amilorida/farmacologia , Animais , Genótipo , Cloreto de Lítio/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Canais de Cátion TRPV/genética , Água/químicaRESUMO
The role of diet temperature in ingestive behavior is poorly understood. We examined the importance of stimulus temperature and water-restriction state on the preference for and intake of water and sucrose. Using custom-designed equipment that allows us to monitor and maintain solution temperatures during testing (±0.1 °C), we conducted a series of 2-bottle preference tests (10 °C water vs. sucrose 10-40 °C) and brief access tests (10-40 °C water and sucrose). Water-restricted rats preferred cold water over any sucrose concentration (0.0-1.0 M) if the sucrose was 30 or 40 °C, whereas the same rats preferred sucrose at all concentrations and temperatures when unrestricted suggesting that the water-restriction state interacts with temperature preference. In a series of brief-access tests using a Davis Rig (MS-180), rats reduced licking to cold sucrose compared with 20 °C sucrose, suggesting that unlike water, cold temperature reduced the palatability of sucrose.
Assuntos
Preferências Alimentares/fisiologia , Sacarose/metabolismo , Temperatura , Água/fisiologia , Animais , Análise por Conglomerados , Temperatura Baixa , Masculino , Ratos , Ratos Sprague-Dawley , Paladar/fisiologiaRESUMO
The purpose of this study was to investigate the role of response latency in discrimination of chemical stimuli by geniculate ganglion neurons in the rat. Accordingly, we recorded single-cell 5-s responses from geniculate ganglion neurons (n = 47) simultaneously with stimulus-evoked summated potentials (electrogustogram; EGG) from the anterior tongue to signal when the stimulus contacted the lingual epithelium. Artificial saliva served as the rinse solution and solvent for all stimuli [(0.5 M sucrose, 0.03-0.5 M NaCl, 0.01 M citric acid, and 0.02 M quinine hydrochloride (QHCl)], 0.1 M KCl as well as for 0.1 M NaCl +1 µM benzamil. Cluster analysis separated neurons into four groups (sucrose specialists, NaCl specialists, NaCl/QHCl generalists and acid generalists). Artificial saliva elevated spontaneous firing rate and response frequency of all neurons. As a rule, geniculate ganglion neurons responded with the highest frequency and shortest latency to their best stimulus with acid generalist the only exception. For specialist neurons and NaCl/QHCl generalists, the average response latency to the best stimulus was two to four times shorter than the latency to secondary stimuli. For NaCl-specialist neurons, response frequency increased and response latency decreased systematically with increasing NaCl concentration; benzamil significantly decreased NaCl response frequency and increased response latency. Acid-generalist neurons had the highest spontaneous firing rate and were the only group that responded consistently to citric acid and KCl. For many acid generalists, a citric-acid-evoked inhibition preceded robust excitation. We conclude that response latency may be an informative coding signal for peripheral chemosensory neurons.
Assuntos
Gânglio Geniculado/fisiologia , Nervo Lingual/fisiologia , Tempo de Reação/fisiologia , Células Receptoras Sensoriais/fisiologia , Paladar/fisiologia , Animais , Ácido Cítrico/farmacologia , Gânglio Geniculado/citologia , Masculino , Modelos Animais , Cloreto de Potássio/farmacologia , Quinina/farmacologia , Ratos , Ratos Sprague-Dawley , Células Receptoras Sensoriais/classificação , Cloreto de Sódio/farmacologia , Estimulação Química , Sacarose/farmacologia , Paladar/efeitos dos fármacosRESUMO
Insights into the biological basis for mammalian taste quality coding began with electrophysiological recordings from "taste" nerves and this technique continues to produce essential information today. Chorda tympani (geniculate ganglion) neurons, which are particularly involved in taste quality discrimination, are specialists or generalists. Specialists respond to stimuli characterized by a single taste quality as defined by behavioral cross-generalization in conditioned taste tests. Generalists respond to electrolytes that elicit multiple aversive qualities. Na(+)-salt (N) specialists in rodents and sweet-stimulus (S) specialists in multiple orders of mammals are well characterized. Specialists are associated with species' nutritional needs and their activation is known to be malleable by internal physiological conditions and contaminated external caloric sources. S specialists, associated with the heterodimeric G-protein coupled receptor T1R, and N specialists, associated with the epithelial sodium channel ENaC, are consistent with labeled line coding from taste bud to afferent neuron. Yet, S-specialist neurons and behavior are less specific than T1R2-3 in encompassing glutamate and E generalist neurons are much less specific than a candidate, PDK TRP channel, sour receptor in encompassing salts and bitter stimuli. Specialist labeled lines for nutrients and generalist patterns for aversive electrolytes may be transmitting taste information to the brain side by side. However, specific roles of generalists in taste quality coding may be resolved by selecting stimuli and stimulus levels found in natural situations. T2Rs, participating in reflexes via the glossopharynygeal nerve, became highly diversified in mammalian phylogenesis as they evolved to deal with dangerous substances within specific environmental niches. Establishing the information afferent neurons traffic to the brain about natural taste stimuli imbedded in dynamic complex mixtures will ultimately "crack taste codes."
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Células Receptoras Sensoriais/fisiologia , Paladar/fisiologia , Animais , Humanos , Rede Nervosa/fisiologia , Receptores de Superfície Celular/fisiologia , Células Receptoras Sensoriais/classificação , Estimulação QuímicaRESUMO
Frailty is a geriatric syndrome characterized by diminished muscle strength, endurance, and weakened physical function. Physical frailty is often unaddressed clinically as it tends to manifest among chronic illnesses and sarcopenia, and consensus criteria for frailty diagnosis remains elusive. Whole-body vibration training (WBVT) has been used to improve deficits in lower body muscular strength and functional performance in healthy and high functioning older adults; therefore, the purpose of this study was to determine the effects of WBVT on physical frailty in skilled nursing home residents. This study compared the effects of 12 wks (2x/wk) of WBVT (n = 10) to standard care, which served as the control (CON: n = 10), on isometric knee extension strength (KE), body composition, and functional performance in 20 (16 female) pre-frail and frail skilled nursing home residents (82 ± 5 yrs). Frailty was assessed using the FRAIL scale and function was measured using the short physical performance battery (SPPB). WBVT consisted of 4 lower body exercises (partial squat, narrow squat, wide squat, calf raise) during vertical vibration (25 - 40 Hz). Data were analyzed using two-way ANOVA (group × time) and post-hoc paired and independent t-tests. Significance was set at p ≤ 0.05. There were significant group-by-time interactions for KE and SPPB. Post-hoc paired t-tests revealed that WBVT improved KE (22.3 ± 4.0 to 29.0 ± 4.5 kg) and improvement in SPPB performance approached significance (4.5 ± 2.3 to 5.2 ± 2.1 units, p = 0.089). WBVT was well tolerated and occurred without adverse health complications. WBVT can be used to counteract losses in leg strength without adverse health complications in skilled nursing home residents.
RESUMO
Paradoxically, bilateral transection of the chorda tympani nerve (CTX) raises the taste discrimination threshold for the free fatty acid, linoleic acid (LA), yet the chorda tympani nerve (CT) is unresponsive to lingual application of LA alone. LA may require a background of saliva to activate taste cells, since CTX decreases saliva production through denervation of the submaxillary and sublingual salivary glands. To assess the role of saliva, we measured LA taste discrimination thresholds for animals whose submaxillary and sublingual salivary glands were removed and also recorded CT responses to LA mixed in artificial saliva. Partial desalivation shifted LA discrimination thresholds from between 5.5 and 11 microM to between 11 and 22 microM. However, this effect was not as pronounced as previously seen with CTX animals. Surprisingly, the CT was unresponsive to LA mixed with artificial saliva, suggesting that artificial saliva may lack components necessary for LA taste. Additionally, fats may primarily enhance other tastes. We previously reported that LA increases CT responses to monosodium glutamate (MSG). Thus we also recorded CT whole nerve responses to taste mixtures of LA and sodium chloride (NaCl), sucrose (SUC), citric acid (CA), or quinine hydrochloride (QHCl) in anesthetized rats. We found that LA increased CT responses to NaCl but did not alter CT responses to SUC, CA, and QHCl. Thus CT recordings either lack the sensitivity to detect small changes to SUC, CA, and QHCl or LA may affect CT responses to MSG and NaCl only, perhaps by specifically modulating gustatory processing of Na(+).
Assuntos
Comportamento Animal , Nervo da Corda do Tímpano/metabolismo , Ácido Linoleico/metabolismo , Saliva/metabolismo , Glândulas Salivares/metabolismo , Papilas Gustativas/metabolismo , Percepção Gustatória , Paladar , Língua/inervação , Animais , Comportamento Animal/efeitos dos fármacos , Nervo da Corda do Tímpano/efeitos dos fármacos , Nervo da Corda do Tímpano/cirurgia , Ácido Cítrico/farmacologia , Denervação , Discriminação Psicológica , Relação Dose-Resposta a Droga , Ácido Linoleico/administração & dosagem , Masculino , Quinina/farmacologia , Ratos , Ratos Sprague-Dawley , Glândulas Salivares/efeitos dos fármacos , Glândulas Salivares/inervação , Cloreto de Sódio/farmacologia , Sacarose/farmacologia , Paladar/efeitos dos fármacos , Papilas Gustativas/efeitos dos fármacos , Percepção Gustatória/efeitos dos fármacos , Limiar GustativoRESUMO
This study investigated the effect of acute full-body resistance exercise [RE; one set of 10 repetitions at 40% 1 repetition maximum (1RM) and three sets of 10 repetitions at 65% 1RM] on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and whole body substrate oxidation in young (age: 22 ± 1 yr), normal-weight and body fatness (body mass index: 20 ± 1 kg/m2; %body fat: 28.7 ± 1.4%), resistance-trained women. Microdialysis was used to measure SCAAT lipolysis at baseline, mid-RE, post-RE, and 30 min post-RE, and indirect calorimetry was used to measure whole body substrate oxidation at baseline and immediately post-RE in 13 women. Plasma concentrations of glucose, insulin, nonesterified fatty acids (NEFA), glycerol, growth hormone (GH), epinephrine (Epi), and norepinephrine (NE) were measured at baseline, mid-RE, and post-RE. Lipolysis (dialysate glycerol concentration) was elevated post-RE (baseline: 596.7 ± 82.8, post-RE: 961.4 ± 116.3 µM, P = 0.01). Energy expenditure (baseline: 1,560 ± 49; post-RE: 1,756 ± 68 kcal/day; P = 0.02) and fat oxidation (baseline: 5.64 ± 0.24; post-RE: 7.57 ± 0.41 g/h; P = 0.0003) were elevated post-RE. GH (baseline: 513.1 ± 147.4; mid-RE: 1,288.3 ± 83.9; post-RE: 1,522.8 ± 51.1 pg/ml, P = 0.000), Epi (baseline: 23.2 ± 2.7; mid-RE: 92.5 ± 16.6; post-RE: 84.5 ± 21.4 pg/ml, P = 0.000), and NE (baseline: 139.2 ± 13.6; mid-RE: 850.9 ± 155.3; post-RE: 695.3 ± 93.5 pg/ml, P = 0.000) were higher at mid-RE and post-RE. Therefore, one of the potential mechanisms behind RE-induced fat mass changes in resistance-trained women may be in part due to the accumulated effect of transient increases in SCAAT lipolysis, fat oxidation, and energy expenditure, mediated by GH, Epi, and NE release.
Assuntos
Exercício Físico/fisiologia , Metabolismo dos Lipídeos/fisiologia , Adolescente , Adulto , Glicemia/metabolismo , Composição Corporal/fisiologia , Índice de Massa Corporal , Calorimetria Indireta/métodos , Metabolismo Energético/fisiologia , Epinefrina/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Feminino , Glicerol/metabolismo , Hormônio do Crescimento Humano/metabolismo , Humanos , Insulina/metabolismo , Lipólise/fisiologia , Norepinefrina/metabolismo , Obesidade/metabolismo , Obesidade/fisiopatologia , Consumo de Oxigênio/fisiologia , Treinamento Resistido/métodos , Gordura Subcutânea Abdominal/metabolismo , Gordura Subcutânea Abdominal/fisiopatologia , Adulto JovemRESUMO
Taste stimuli are normally dissolved in saliva prior to interacting with their respective receptor targets. There are hundreds of proteins in saliva, and it has been hypothesized that these proteins could interact with either taste stimuli or taste receptors to alter taste signaling and diet acceptance. However, the impact of these proteins on feeding has been relatively unexplored using rodent models. We have developed a novel technique for saliva collection that allows us to link salivary protein expression with feeding behavior. First, we monitored the microstructure of rats' feeding patterns on a 0.375% quinine diet (Q-diet) while tracking changes in salivary protein expression. We found 5 protein bands were upregulated by diet exposure to Q-diet and upregulation of a subset of these bands were statistically related to increased diet acceptance, including changes in behavioral measures that are thought to represent both orosensory and postingestive signaling. In a second experiment, we measured the licking to a range of quinine solutions (0.01-1.0mM) before and after the animals were exposed to a tannic acid diet that altered salivary protein expression. Rats found the quinine solutions less aversive after salivary protein altering diets. In a third experiment we recorded the response of the chorda tympani (CT) nerve while delivering quinine solutions (0.3-30mM) to the front of the tongue dissolved in either "donor saliva" containing salivary proteins or donor saliva which has had the salivary proteins removed. Donor saliva was collected from a separate group of animals using isoproterenol and pilocarpine. The samples containing salivary proteins resulted in lower nerve responses than those without salivary proteins. Together these data suggest that salivary proteins are capable of altering taste-guided behaviors and taste nerve signaling.
Assuntos
Comportamento Alimentar/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Saliva/metabolismo , Proteínas e Peptídeos Salivares/metabolismo , Papilas Gustativas/fisiologia , Paladar/fisiologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Análise de Variância , Animais , Nervo da Corda do Tímpano/efeitos dos fármacos , Nervo da Corda do Tímpano/fisiologia , Densitometria , Dieta , Comportamento Alimentar/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Masculino , Peso Molecular , Quinina/farmacologia , Ratos , Ratos Long-Evans , Saliva/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Taninos/farmacologia , Paladar/efeitos dos fármacos , Papilas Gustativas/efeitos dos fármacosRESUMO
AIM: To investigate the prevalence of sarcopenic obesity (SO) and its association with health outcomes in patients seeking weight loss treatment from a bariatric center. METHODS: In this retrospective study, patients [≥18 years old, body mass index (BMI) ≥30 kg/m2] from the Tallahassee Memorial Bariatric Center and with baseline body composition assessment by bioelectrical impedance analysis were included. Fat mass index (FMI = fat mass/height2) and fat-free mass index (FFMI = fat free mass/height2) were calculated. SO was defined by a FMI/FFMI ratio greater than the 95 percentile of sex, BMI and ethnicity specific population-representative references. Medical records were reviewed for biochemical and comorbidity measures. RESULTS: One hundred and forty-four patients (â¼69% females, mean age 55.6 years, mean BMI 46.6 kg/m2) were included. Patients' FMI/FFMI ratios ranged from 0.35 to 1.60 kg/m2 across body weight spectrum, with 51% having SO. Blood pressure, fasting glucose, triglycerides, HDL or LDL were not different between patients with and without SO. However, the prevalence of high cholesterol, asthma, alcoholism and hernia were higher in patients with SO. SO was the strongest univariate predictor of high cholesterol (OR = 2.08, 95% CI 1.07-4.04) and asthma (OR = 2.77, 95% CI = 1.12-6.83). CONCLUSION: SO was prevalent and associated with adverse health outcomes, beyond that captured by anthropometric measures in the present study.
Assuntos
Obesidade/epidemiologia , Sarcopenia/epidemiologia , Redução de Peso , Programas de Redução de Peso , Glicemia/metabolismo , Pressão Sanguínea , Composição Corporal , Índice de Massa Corporal , Colesterol/sangue , Comorbidade , Impedância Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Triglicerídeos/sangueRESUMO
We tested the hypothesis that sex differences in preference for NaCl are attributable to estrogen-mediated alterations in gustatory processing. Electrophysiological responses of the chorda tympani nerve to NaCl were blunted by estrogen treatment in ovariectomized female rats, suggesting that females are less sensitive to concentrated NaCl solutions during high estrogen conditions. In contrast, after a taste aversion was conditioned to 150-mM NaCl, estrogen- and oil-treated ovariectomized rats generalized the aversion to a lower concentration of NaCl than did males, suggesting that females are more sensitive to the taste of dilute NaCl solutions regardless of estrogen. Thus, sex differences in NaCl preferences may be attributable to differences in NaCl taste processing that involve both acute and developmental effects of estrogen.
Assuntos
Comportamento Animal/fisiologia , Nervo da Corda do Tímpano/efeitos dos fármacos , Caracteres Sexuais , Cloreto de Sódio/farmacologia , Paladar/fisiologia , Animais , Área Sob a Curva , Comportamento Animal/efeitos dos fármacos , Nervo da Corda do Tímpano/fisiologia , Relação Dose-Resposta a Droga , Eletrofisiologia , Estradiol/análogos & derivados , Estradiol/farmacologia , Feminino , Masculino , Ovariectomia/métodos , Ratos , Ratos Sprague-Dawley , Paladar/efeitos dos fármacosRESUMO
Taste is intimately associated with food choice, yet little is known about the role of taste in preferences for dietary fat, a major component of many foods. We measured the taste threshold for linoleic acid (LA), an essential free fatty acid found in dietary fat, before and after bilateral transections of the chorda tympani nerve (CTX) in adult male and female rats. We conditioned a taste aversion to 88 microM LA and assessed the generalization of the aversion to lower LA concentrations to determine LA discrimination thresholds. We discovered that female rats had a lower LA discrimination threshold (approximately 2.75 microM LA) than did male rats (approximately 11 microM LA). In another set of animals, we performed CTX and found that CTX elevated LA threshold to the same level (approximately 22 microM LA) in male and female rats. Finally, we evaluated licking responses to 11, 22, 44 and 88 microM LA mixed in sucrose by male rats and ovariectomized (OVX) female rats treated with estradiol benzoate or oil vehicle. All rats increased licking to increasing LA concentrations, but OVX rats responded to a lower LA concentration (22 microM) than did males (44 microM) in 10-s trials. However, estradiol did not affect this outcome. Collectively, these experiments show that male and female rats use taste to discriminate LA and that the chorda tympani nerve, which innervates taste buds on the anterior tongue, plays a role in this discrimination. Furthermore, sex differences in fat preferences may depend on differences in fatty acid taste thresholds as well as on the taste stimuli with which fat is combined.
Assuntos
Nervo da Corda do Tímpano , Discriminação Psicológica/fisiologia , Doenças do Nervo Facial/fisiopatologia , Ácido Linoleico , Paladar/fisiologia , Análise de Variância , Animais , Comportamento Animal , Peso Corporal/fisiologia , Depressores do Sistema Nervoso Central/farmacologia , Discriminação Psicológica/efeitos dos fármacos , Relação Dose-Resposta a Droga , Comportamento de Ingestão de Líquido/fisiologia , Interações Medicamentosas , Etanol/farmacologia , Feminino , Preferências Alimentares/efeitos dos fármacos , Preferências Alimentares/fisiologia , Masculino , Ovariectomia/métodos , Ratos , Ratos Sprague-Dawley , Fatores Sexuais , Sacarose/farmacologia , Edulcorantes , Paladar/efeitos dos fármacos , Limiar Gustativo/efeitos dos fármacos , Limiar Gustativo/fisiologiaRESUMO
The timing of morning endurance competition may limit proper pre-race fueling and resulting performance. A nighttime, pre-sleep nutritional strategy could be an alternative method to target the metabolic and hydrating needs of the early morning athlete without compromising sleep or gastrointestinal comfort during exercise. Therefore, the purpose of this investigation was to examine the acute effects of pre-sleep chocolate milk (CM) ingestion on next-morning running performance, metabolism, and hydration status. Twelve competitive female runners and triathletes (age, 30 ± 7 years; peak oxygen consumption, 53 ± 4 mL·kg(-1)·min(-1)) randomly ingested either pre-sleep CM or non-nutritive placebo (PL) â¼30 min before sleep and 7-9 h before a morning exercise trial. Resting metabolic rate (RMR) was assessed prior to exercise. The exercise trial included a warm-up, three 5-min incremental workloads at 55%, 65%, and 75% peak oxygen consumption, and a 10-km treadmill time trial (TT). Physiological responses were assessed prior, during (incremental and TT), and postexercise. Paired t tests and magnitude-based inferences were used to determine treatment differences. TT performances were not different ("most likely trivial" improvement with CM) between conditions (PL: 52.8 ± 8.4 min vs CM: 52.8 ± 8.0 min). RMR was "likely" increased (4.8%) and total carbohydrate oxidation (g·min(-1)) during exercise was "possibly" or likely increased (18.8%, 10.1%, 9.1% for stage 1-3, respectively) with CM versus PL. There were no consistent changes to hydration indices. In conclusion, pre-sleep CM may alter next-morning resting and exercise metabolism to favor carbohydrate oxidation, but effects did not translate to 10-km running performance improvements.
Assuntos
Atletas , Desempenho Atlético , Corrida/fisiologia , Fenômenos Fisiológicos da Nutrição Esportiva , Fatores de Tempo , Adulto , Animais , Apetite , Metabolismo Basal , Glicemia/metabolismo , Peso Corporal , Chocolate/análise , Estudos Cross-Over , Dieta , Carboidratos da Dieta/administração & dosagem , Método Duplo-Cego , Teste de Esforço , Feminino , Frequência Cardíaca , Humanos , Leite/química , Oxirredução , Consumo de Oxigênio , Progesterona/análise , Saliva/química , Sono , Adulto JovemRESUMO
We have previously shown that ingesting protein at night before sleep is either beneficial or non-detrimental to metabolism, health, and body composition in obese women. However, the overnight protein-induced lipolytic actions and mechanism for improved metabolism and body composition have not been fully established. Therefore, in a crossover design, twelve obese men (age, 27.0 ± 2.2 years) were randomly assigned to ingest (within 30 min of sleep) casein protein (CAS, 120 kcal) or a non-nutritive placebo (PLA) before going to sleep. Markers of fat metabolism (lipolysis, substrate utilization, growth hormone), insulin, glucose, resting energy expenditure (REE), and appetite (questionnaire and ghrelin) were measured. During sleep and the next morning, interstitial glycerol from the subcutaneous abdominal adipose tissue (SCAAT) was measured using microdialysis. There were no differences in SCAAT glycerol (overnight: CAS, 177.4 ± 26.7; PLA, 183.8 ± 20.2 µmol/L; morning: CAS, 171.6 ± 19.1; PLA, 161.5 ± 18.6 µmol/L), substrate utilization, REE, or any blood markers between CAS and PLA. Desire to eat was greater for CAS compared to baseline (p = 0.03), but not different from PLA (baseline: 39 ± 6, CAS: 62 ± 8, PLA: 55 ± 5 mm). CAS consumption before sleep did not affect fat or glucose metabolism, REE, or suppress appetite in hyperinsulemic obese men. CAS may be consumed before sleep without impeding overnight or morning fat metabolism in young, obese men.