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1.
Behav Brain Res ; 459: 114800, 2024 02 29.
Artículo en Inglés | MEDLINE | ID: mdl-38061669

RESUMEN

A first-order association can be formed between toxin-induced nausea and a context, as well as nausea and a taste cue. However, comparatively little is understood about second-order associations. The present study examined if the bacterial endotoxin, LPS, could impair the first- and second-order conditioning of context aversion (anticipatory nausea paradigm) and subsequent conditioned taste avoidance (two-bottle task). Adult male Long Evans rats were treated with LiCl (127 mg/kg, intraperitoneal [i.p.]) or vehicle control (NaCl) and then exposed to a distinct context for 4 first-order conditioning trials. LPS (200 µg/kg, i.p.) or NaCl were administered 24 h after each trial. Seventy-two h after the final first-order conditioning trial, rats underwent 2 second-order conditioning trials where they were treated with 2% saccharin (i.p.) and then exposed to the same context. Twenty-four h after the final second-order conditioning trial, rats were tested in a two-bottle task (2 trials), where they were given a choice between water and a palatable 0.2% saccharin solution. LiCl-treated rats demonstrated a context aversion by the 3rd conditioning trial in the anticipatory nausea paradigm. Rats previously exposed to LiCl also displayed a conditioned taste avoidance of saccharin within the two-bottle task. LPS attenuated first-order context aversion but did not alter either second-order context aversion or conditioned taste avoidance in the two-bottle task. This study demonstrated that a secondary association formed within an aversive context could result in a conditioned taste avoidance. Further, LPS may be able to attenuate primary conditioning, but not secondary conditioning.


Asunto(s)
Lipopolisacáridos , Cloruro de Litio , Ratas , Masculino , Animales , Lipopolisacáridos/efectos adversos , Cloruro de Litio/efectos adversos , Ratas Long-Evans , Sacarina/farmacología , Gusto , Cloruro de Sodio , Reacción de Prevención , Náusea/inducido químicamente
2.
Exp Clin Psychopharmacol ; 32(2): 158-172, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37535523

RESUMEN

The present study used a rat choice model to test how cocaine or heroin economically interacted with two different nondrug reinforcers along the substitute-to-complement continuum. In Experiment 1, the nondrug alternative was the negative reinforcer timeout-from-avoidance (TOA)-that is, rats could press a lever to obtain a period of safety from footshock. One group of rats chose between cocaine and TOA and another group chose between heroin and TOA. The relative prices of the reinforcers were manipulated across phases while controlling for potential income effects. When cocaine was the reinforcer, rats reacted to price changes by increasing their allocation of behavior to the more expensive option, thereby maintaining relatively proportional intake of cocaine and TOA reinforcers across prices, suggesting these reinforcers were complements here. In contrast, when heroin became relatively cheap, rats increased allocation of income to heroin and decreased allocation of income to TOA, suggesting that heroin substituted for safety. Additionally, rats were willing to accept more footshocks when heroin was easily available. In Experiment 2, the nondrug alternative was saccharin, a positive reinforcer. Heroin and saccharin were complements, but there was no consistent effect of price changes on the allocation of behavior between cocaine and saccharin. As a model of the processes that could be involved in human drug use, these results show that drug-taking behavior depends on the type of drug, the type of nondrug alternative available, and the prices of both. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Asunto(s)
Cocaína , Heroína , Humanos , Ratas , Animales , Heroína/farmacología , Sacarina/farmacología , Conducta de Elección , Autoadministración , Cocaína/farmacología
3.
Can J Physiol Pharmacol ; 102(2): 116-127, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-37748201

RESUMEN

Non-nutritive sweeteners are popular food additives owing to their low caloric density and powerful sweetness relative to natural sugars. Their lack of metabolism contributes to evidence proclaiming their safety, yet several studies contradict this, demonstrating that sweeteners activate sweet taste G protein-coupled receptors (GPCRs) and elicit deleterious metabolic functions through unknown mechanisms. We hypothesize that activation of GPCRs, particularly orphan receptors due to their abundance in metabolically active tissues, contributes to the biological activity of sweeteners. We quantified the response of 64 orphans to the sweeteners saccharin and sucralose using a high-throughput ß-arrestin-2 recruitment assay (PRESTO-Tango). GPR52 was the sole receptor that significantly responded to a mixture of sucralose and saccharin. Subsequent experiments revealed sucralose as the activating sweetener. Activation of GPR52 was concentration-dependent, with an EC50 of 0.23 mmol/L and an Emax of 3.43 ± 0.24 fold change at 4 mmol/L. GPR52 constitutively activates CRE pathways; however, we show that sucralose-induced activation of GPR52 does not further activate this pathway. Identification of this novel sucralose-GPCR interaction supports the notion that sucralose elicits off-target signaling through the activation of GPR52, calling into question sucralose's assumed lack of bioactivity.


Asunto(s)
Edulcorantes no Nutritivos , Edulcorantes , Edulcorantes/farmacología , Edulcorantes no Nutritivos/farmacología , Sacarina/farmacología , beta-Arrestinas , Sacarosa/farmacología , Receptores Acoplados a Proteínas G
4.
Behav Processes ; 214: 104974, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38043720

RESUMEN

Three experiments were conducted to investigate Conditioned Olfactory Preferences using orthonasal inhalation, which is a less explored perceptual pathway compared to retronasal inhalation. In these experiments, odors were impregnated onto plastic disks to prevent the subjects from consuming or tasting them. The reinforcers used were a sucrose solution (Caloric groups) and a saccharin solution (Non-Caloric groups). The influence of nutritional deprivation was analyzed, with unrestricted access to food throughout the procedure in Experiment 1, food restriction during the conditioning phase in Experiment 2, and limited access to food during the test phase in Experiment 3. The results revealed conditioned preferences using both sucrose and saccharin as reinforcers. Furthermore, dietary restriction reduced the conditioned preference induced by saccharin, but not the preference induced by sucrose. These findings are discussed in light of the potential differences between orthonasal and retronasal presentation of odors during conditioning.


Asunto(s)
Privación de Alimentos , Sacarina , Humanos , Sacarina/farmacología , Olfato , Odorantes , Sacarosa/farmacología
5.
Brain Res ; 1822: 148617, 2024 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-37805008

RESUMEN

Conditioned taste aversion (CTA) is an essential ability for animals to consume food safely and is regulated by neuromodulatory systems including the dopamine, noradrenaline, serotonin, and acetylcholine systems. However, because few studies focused on a comprehensive understanding of whole-brain activities, how these neuromodulators contribute to the process of CTA remains an open issue. 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) can visualize activated regions within the whole brain simultaneously and noninvasively. This study aimed to understand the mechanisms of CTA, especially focusing on the retrieval process after CTA acquisition by FDG-PET imaging. CTA was established in rats who received an intraoral application of saccharin solution (IOAS) on the first day (Day 1), a LiCl i.p. injection after an IOAS on Day 2, and an IOAS on Day 3 (CTA group). The subtraction images of Day 3 of the SHAM group, which received a 0.9 % NaCl (saline) injection instead of a LiCl on Day 2, from those of Day 3 of the CTA group revealed increases in FDG signals in multiple brain regions including the substantia nigra, ventral tegmental area, locus coeruleus, dorsal raphe, and nucleus basalis magnocellularis, in addition to the hippocampus and nociception-related regions, including the parabrachial nucleus and solitary nucleus. On the other hand, the visceral pain induced by the LiCl injection increased FDG signals in the primary and secondary somatosensory and insular cortices in addition to the parabrachial nucleus and solitary nucleus. These results suggest that the retrieval process of CTA induces brain regions producing neuromodulators and pain-related brainstem.


Asunto(s)
Fluorodesoxiglucosa F18 , Gusto , Ratas , Animales , Gusto/fisiología , Cloruro de Litio , Reacción de Prevención/fisiología , Núcleo Solitario , Sacarina/farmacología , Tomografía de Emisión de Positrones , Neurotransmisores
6.
Nutrition ; 117: 112237, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37897982

RESUMEN

Use of non-nutritive sweeteners (NNSs) has increased worldwide in recent decades. However, evidence from preclinical studies shows that sweetener consumption may induce glucose intolerance through changes in the gut microbiota, which raises public health concerns. As studies conducted on humans are lacking, the aim of this review was to gather and summarize the current evidence on the effects of NNSs on human gut microbiota. Only clinical trials and cross-sectional studies were included in the review. Regarding NNSs (i.e, saccharin, sucralose, aspartame, and stevia), only two of five clinical trials showed significant changes in gut microbiota composition after the intervention protocol. These studies concluded that saccharin and sucralose impair glycemic tolerance. In three of the four cross-sectional studies an association between NNSs and the microbial composition was observed. All three clinical trials on polyols (i.e, xylitol) showed prebiotic effects on gut microbiota, but these studies had multiple limitations (publication date, dosage, duration) that jeopardize their validity. The microbial response to NNSs consumption could be strongly mediated by the gut microbial composition at baseline. Further studies in which the potential personalized microbial response to NNSs consumption is acknowledged, and that include longer intervention protocols, larger cohorts, and more realistic sweetener dosage are needed to broaden these findings.


Asunto(s)
Microbioma Gastrointestinal , Edulcorantes no Nutritivos , Humanos , Edulcorantes/farmacología , Sacarina/farmacología , Estudios Transversales , Edulcorantes no Nutritivos/efectos adversos , Edulcorantes no Nutritivos/análisis
7.
Behav Processes ; 214: 104984, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38103808

RESUMEN

Increased reinforcer motivation in rats has been repeatedly demonstrated following intermittent-access (IntA) training, where the reinforcer is only available for brief periods during a session, compared to continuous-access (ContA) training where the reinforcer is available throughout the session. The present study investigated whether different associations learned during training on the two procedures contributes to the effect. Two experiments tested the importance of the stimulus-response (S-R) and stimulus-outcome (S-O) associations between the IntA availability cues and the training response and reinforcer, respectively. In Exp. 1, separate groups of rats were trained to lever press for saccharin on the IntA or ContA procedures. Increased motivation for saccharin was observed in the IntA group on a later progressive ratio test where nosepoking was the operant (but not when lever pressing was the operant). The outcome of the nosepoke test suggests that a potential S-R association formed during IntA training was not critical for the effect. In Exp. 2, increased saccharin motivation (on nosepoke tests) after IntA training (with lever pressing) was observed regardless of the presence or absence of IntA availability cues, indicating that the S-O association formed during training is not critical for the effect either. Overall, these results suggest that the elemental associations learned on IntA procedures may not be what drives increased motivation observed after IntA training.


Asunto(s)
Refuerzo en Psicología , Sacarina , Ratas , Animales , Sacarina/farmacología , Motivación , Condicionamiento Operante , Aprendizaje , Autoadministración
8.
Int J Mol Sci ; 24(19)2023 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-37833894

RESUMEN

The purpose of this study was to confirm the antiproliferative and apoptotic induction potential of a saccharin and caffeine combination in ovarian cancer cells. The cell line used was Ovcar-3, and the cell viability was measured through a WST-8 assay, while a Chou-Talalay assay was used to confirm the synergistic effect of saccharin and caffeine on the ovarian cancer cells. A clonogenic assay, annexin V-FITC/PI-PE double-staining, and RT-PCR were performed to confirm the expression of genes that induce colony formation, cell viability, and apoptosis in ovarian cancer cells treated with the saccharin-caffeine combination. It was demonstrated that both saccharin and caffeine decreased the viability of Ovcar-3 cells, and the cell viability decreased even more significantly when the cells were treated with the combination of saccharin and caffeine. The clonogenic assay results showed that the number of colonies decreased the most when saccharin and caffeine were combined, and the number of colonies also significantly decreased compared to the single-treatment groups. Based on flow cytometry analysis using annexin V-FITC/PI-PE double-staining, it was confirmed that the decrease in cell viability caused by the combination of saccharin and caffeine was correlated with the induction of apoptosis. The results of the RT-PCR confirmed that the combined treatment of saccharin and caffeine promoted cell apoptosis by regulating the expression of apoptosis-inducing genes. These results demonstrate that the combination of saccharin and caffeine more efficiently inhibits the proliferation of Ovcar-3 cells and induces apoptosis in vitro.


Asunto(s)
Neoplasias Ováricas , Humanos , Femenino , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/genética , Neoplasias Ováricas/metabolismo , Cafeína/farmacología , Apoptosis , Sacarina/farmacología , Proliferación Celular , Línea Celular Tumoral , Carcinoma Epitelial de Ovario
9.
Physiol Behav ; 272: 114381, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37866642

RESUMEN

The main aim of this experiment was to examine the claim that exposure to non-nutritive sweeteners weakens the formation of a sweet-calorie association. Three groups of food-deprived rats received training in which they drank an almond-flavored maltodextrin and saccharin solution. A final test phase assessed their preference for almond. The groups differed in preexposure prior to training. One was pre-exposed to saccharin, one to saccharin plus maltodextrin, and the third, control condition, received only water at this stage. When the rats continued under food deprivation for the test phase, the group exposed to the compound (saccharin plus maltodextrin) showed a weaker preference than the other two groups, while those pre-exposed to saccharin showed as strong a preference as the controls. When the test was conducted with the rats no longer food-deprived, only the water group showed a strong preference. These results support the proposal that rats can form both flavor-flavor and flavor-nutrient associations, expression of which will depend on motivational state. They did not find support for the suggestion that prior exposure to a non-nutritive sweetener can enhance subsequent learning about the nutritive properties of a sweet food.


Asunto(s)
Preferencias Alimentarias , Sacarina , Ratas , Animales , Sacarina/farmacología , Aprendizaje , Edulcorantes/farmacología , Gusto , Agua
10.
ChemMedChem ; 18(22): e202300454, 2023 11 16.
Artículo en Inglés | MEDLINE | ID: mdl-37837260

RESUMEN

This study explores the binding mechanisms of saccharin derivatives with human carbonic anhydrase IX (hCA IX), an antitumor drug target, with the aim of facilitating the design of potent and selective inhibitors. Through the use of crystallographic analysis, we investigate the structures of hCA IX-saccharin derivative complexes, unveiling their unique binding modes that exhibit both similarities to sulfonamides and distinct orientations of the ligand tail. Our comprehensive structural insights provide information regarding the crucial interactions between the ligands and the protein, shedding light on interactions that dictate inhibitor binding and selectivity. Through a comparative analysis of the binding modes observed in hCA II and hCA IX, isoform-specific interactions are identified, offering promising strategies for the development of isoform-selective inhibitors that specifically target tumor-associated hCA IX. The findings of this study significantly deepen our understanding of the binding mechanisms of hCA inhibitors, laying a solid foundation for the rational design of more effective inhibitors.


Asunto(s)
Anhidrasas Carbónicas , Neoplasias , Humanos , Anhidrasa Carbónica IX/metabolismo , Sacarina/farmacología , Sacarina/química , Anhidrasas Carbónicas/metabolismo , Antígenos de Neoplasias/metabolismo , Isoformas de Proteínas/metabolismo , Inhibidores de Anhidrasa Carbónica/química , Relación Estructura-Actividad , Estructura Molecular
11.
Psicothema ; 35(4): 423-431, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37882427

RESUMEN

BACKGROUND: Adolescence in mammals is a period marked by increased novelty-seeking and enhanced responsiveness to the stressful properties of novel stimuli. Despite the need to taste potentially toxic novel foods during the adolescent growth spurt, there has been little study of taste neophobia and its attenuation. METHOD: Four experiments were carried out to compare taste neophobia and related memory processes in male and female adolescent (PND28) and adult (PND70) Wistar rats. Experiments 1 and 2 evaluated attenuation of taste neophobia to cider vinegar (3%) and sodium saccharin (0.1%) solutions were evaluated. Additionally, to test the role of memory in neophobia during adolescence, latent inhibition of taste aversion and object recognition memory were assessed in Experiment 3 and Experiment 4, respectively. RESULTS: Adolescent and adult rats exhibited taste neophobia to the saccharin solution but adolescent rats required more exposure trials than adults to recognize the vinegar solution as safe. Both groups exhibited similar latent inhibition of taste aversion and object recognition memory. No sex effect was significant. CONCLUSIONS: Contrary to the accepted view associating adolescence with reduced neophobia, adolescent rats exhibited taste neophobia which even increased when sour tastes were encountered.


Asunto(s)
Sacarina , Gusto , Ratas , Masculino , Femenino , Animales , Gusto/fisiología , Ratas Wistar , Sacarina/farmacología , Ácido Acético/farmacología , Percepción del Gusto/fisiología , Reacción de Prevención/fisiología , Mamíferos
12.
Physiol Behav ; 270: 114317, 2023 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-37541607

RESUMEN

The impacts of high-fat and/or high-sugar diets on opioid-induced effects are well documented; however, little is known about the effect of such diet on the affective responses to opiates. To address this issue, in the present experiment male Sprague-Dawley rats were given ad libitum access to a western-style diet (high in saturated fat and sugar) or a standard laboratory chow diet beginning in adolescence and continuing into adulthood at which point they were trained in a combined conditioned taste avoidance (CTA)/conditioned place preference (CPP) procedure to assess the aversive and rewarding effects of morphine, respectively. On four conditioning cycles, animals were given access to a novel saccharin solution, injected with morphine (1 mg/kg or 5 mg/kg), and then placed on one side of a place preference chamber. Animals were then tested for place preference and saccharin preference. All subjects injected with morphine displayed significant avoidance of the morphine-associated solution (CTA) and preferred the side associated with the drug (CPP). Furthermore, there were no differences between the two diet groups, indicating that chronic exposure to the western diet had no impact on the affective properties of morphine (despite increasing caloric intake, body weight, body fat and lean body mass). Given previously reported increases in drug self-administration in animals with a history of western-diet consumption, this study suggests that western-diet exposure may increase drug intake via mechanisms other than changes in the rewarding or aversive effects of the drug.


Asunto(s)
Morfina , Sacarina , Ratas , Animales , Masculino , Ratas Sprague-Dawley , Morfina/farmacología , Sacarina/farmacología , Dieta Occidental , Gusto/fisiología , Recompensa , Azúcares/farmacología , Reacción de Prevención
13.
Chem Senses ; 482023 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-37387468

RESUMEN

The Occidental High- and Low-Saccharin rats (respectively, HiS and LoS lines) were selectively bred for decades to examine mechanisms and correlates of a saccharin intake phenotype. Observed line differences ranged from taste and eating to drug self-administration and defensive behavior, paralleling human research on relationships between gustation, personality, and psychopathology. The original lines were terminated in 2019, and replicate lines (HiS-R and LoS-R) were selectively bred for 5 generations to test for reproducible, rapid selection for the phenotype and its correlates. The line differences chosen for replication included intake of tastants (saccharin, sugars, quinine-adulterated sucrose, sodium chloride, and ethanol) and foods (cheese, peas, Spam, and chocolate) and several noningestive behaviors (deprivation-induced hyperactivity, acoustic startle, and open field behavior). The HiS-R and LoS-R lines diverged on intake of saccharin, disaccharides, quinine-adulterated sucrose, sodium chloride, and complex foods, and open field behavior. Differences from the original lines also were observed. Reasons for and implications of the pattern of replication and lack thereof in 5 generations are discussed.


Asunto(s)
Quinina , Sacarina , Humanos , Ratas , Animales , Sacarina/farmacología , Quinina/farmacología , Cloruro de Sodio , Fenotipo , Sacarosa/farmacología , Gusto
14.
Physiol Behav ; 269: 114278, 2023 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-37352906

RESUMEN

No prior studies have shown that gaping reactions are produced with the avoidance of conditioned taste caused by cisplatin and emetine. Therefore, we tried to demonstrate it using a taste reactivity test in rats and found the gaping reactions induced when saccharin is readministered after gustatory conditioning that paired saccharin with cisplatin or emetine. Since conditioned gaping reactions indicate the aversion to saccharin taste and conditioned nausea, the present study suggest that the taste aversion is induced by cisplatin and emetine. It was also found that with intraperitoneal injections of emetine alone, gaping almost never occurs.


Asunto(s)
Cisplatino , Emetina , Ratas , Animales , Emetina/efectos adversos , Cisplatino/toxicidad , Sacarina/farmacología , Gusto , Cloruro de Litio/farmacología , Náusea/inducido químicamente , Reacción de Prevención
15.
Pharmacol Biochem Behav ; 225: 173562, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-37156400

RESUMEN

BACKGROUND: Drugs of abuse have rewarding and aversive effects that, in balance, impact abuse potential. Although such effects are generally examined in independent assays (e.g., CPP and CTA, respectively), a number of studies have examined these effects concurrently in rats in a combined CTA/CPP design. The present study assessed if similar effects can be produced in mice which would allow for determining how each is affected by subject and experiential factors relevant to drug use and abuse and the relationship between these affective properties. METHODS: Male and female C57BL/6 mice were exposed to a novel saccharin solution, injected (IP) with saline or 5.6, 10 or 18 mg/kg of the synthetic cathinone, methylone, and placed on one side of the place conditioning apparatus. The following day, they were injected with saline, given access to water and placed on the other side of the apparatus. After four conditioning cycles, saccharin avoidance and place preferences were assessed in a final two-bottle CTA test and a CPP Post-Test, respectively. RESULTS: In the combined CTA/CPP design, mice acquired a significant dose-dependent CTA (p = 0.003) and a significant CPP (p = 0.002). These effects were independent of sex (all ps > 0.05). Further, there was no significant relationship between the degree of taste avoidance and place preference (p > 0.05). CONCLUSIONS: Similar to rats, mice displayed significant CTA and CPP in the combined design. It will be important to extend this design in mice to other drugs and to examine the impact of different subject and experiential factors on these effects to facilitate predictions of abuse liability.


Asunto(s)
Condicionamiento Psicológico , Gusto , Ratas , Ratones , Masculino , Femenino , Animales , Sacarina/farmacología , Ratones Endogámicos C57BL , Recompensa , Reacción de Prevención , Relación Dosis-Respuesta a Droga
16.
Exp Clin Psychopharmacol ; 31(6): 1069-1079, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37227884

RESUMEN

Recently, use of the synthetic cathinone (aka "bath salt") eutylone has risen in the United States and globally. Due to its novelty in drug markets, its affective properties remain largely uninvestigated. In this context, drugs of abuse have both rewarding and aversive effects and understanding these effects, their relative balance, and factors that impact each are important to understanding the likelihood of drug use and abuse. This investigation attempted to characterize eutylone's rewarding and aversive effects in a combined conditioned taste avoidance/place preference assay. Female Sprague-Dawley rats were given 20-min access to saccharin, injected with one of five doses of eutylone (0, 3, 10, 18, 32 mg/kg; intraperitoneally; IP), and placed on one side of a place conditioning apparatus. On the following day, subjects were given 20-min access to water, injected IP with vehicle, and placed on the other side of the apparatus. After five conditioning cycles, place preference and saccharin avoidance were assessed. Eutylone induced significant taste avoidance but did not significantly increase time spent on the drug-paired side (relative to controls). Excluding animals with high initial side preference, however, eutylone induced a preference at all doses with the high dose group displaying higher preference than controls. There was no significant correlation between eutylone's aversive and rewarding effects. These data indicate that eutylone (like other synthetic cathinones) induces both rewarding and aversive effects and highlight the need to assess the impact of various factors on its affective properties (and their balance) and on their use and abuse. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Asunto(s)
Cathinona Sintética , Gusto , Humanos , Ratas , Animales , Femenino , Ratas Sprague-Dawley , Sacarina/farmacología , Reacción de Prevención
17.
Nutrients ; 15(8)2023 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-37111090

RESUMEN

The human gut microbiota, a complex community of microorganisms living in the digestive tract, consists of more than 1500 species distributed in more than 50 different phyla, with 99% of bacteria coming from about 30-40 species. The colon alone, which contains the largest population of the diverse human microbiota, can harbor up to 100 trillion bacteria. The gut microbiota is essential in maintaining normal gut physiology and health. Therefore, its disruption in humans is often associated with various pathological conditions. Different factors can influence the composition and function of the gut microbiota, including host genetics, age, antibiotic treatments, environment, and diet. The diet has a marked effect, impacting the gut microbiota composition, beneficially or detrimentally, by altering some bacterial species and adjusting the metabolites produced in the gut environment. With the widespread use of non-nutritive sweeteners (NNS) in the diet, recent investigations have focused on their effect on the gut microbiota as a mediator of the potential impact generated by gastrointestinal-related disturbances, such as insulin resistance, obesity, and inflammation. We summarized the results from pre-clinical and clinical studies published over the last ten years that examined the single effects of the most consumed NNS: aspartame, acesulfame-K, sucralose, and saccharin. Pre-clinical studies have given conflicting results for various reasons, including the administration method and the differences in metabolism of the same NNS among the different animal species. A dysbiotic effect of NNS was observed in some human trials, but many other randomized controlled trials reported a lack of significant impacts on gut microbiota composition. These studies differed in the number of subjects involved, their dietary habits, and their lifestyle; all factors related to the baseline composition of gut microbiota and their response to NNS. The scientific community still has no unanimous consensus on the appropriate outcomes and biomarkers that can accurately define the effects of NNS on the gut microbiota.


Asunto(s)
Microbioma Gastrointestinal , Edulcorantes no Nutritivos , Animales , Humanos , Edulcorantes no Nutritivos/análisis , Sacarina/farmacología , Dieta , Obesidad/metabolismo
18.
Physiol Behav ; 265: 114143, 2023 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-36898644

RESUMEN

Thirst is an essential motivational component that could modulate the strength of conditioning; pioneer studies show that the rats' sexual dimorphism observed in the rate of aversive memory extinction of conditioned taste aversion (CTA) is affected by the state of fluid deprivation. On the other hand, previous evidence suggests that fluid intake volume and temporal context before and during conditioning may influence CTA. Furthermore, although CTA has been demonstrated using various types of stimuli, neural processing and homeostatic regulation of water and nutritional balance may differ depending on the stimulus used and the conditioning stages. Therefore, this study explored the effects of state motivated by thirst and satiation, using saccharin, as a non-caloric sweet stimulus, during CTA and the aversive memory extinction process under similar contextual and temporal conditions. First, we implemented an ad libitum water protocol in male and female adult rats to evaluate saccharin aversive memory formation; we compared this with a traditional CTA with liquid deprivation in the same context and temporal consumption conditions. Furthermore, we evaluated whether liquid satiety affects the acquisition or the aversive memory retrieval differentially. Our results show that the ad libitum liquid regimen allows reliable quantifications of basal water consumption, monitored every hour for more than five days. We observed a reliable CTA, where the magnitude of aversive memory and its extinction is significantly higher in both male and female rats; the strong CTA observed is substantially due to the satiety state during taste aversion memory retrieval. Our data show that although liquid deprivation does not affect CTA acquisition, it does induce weakness in the magnitude of aversive retrieval expression and fast aversive memory extinction, similarly in male and females. Overall, the results indicate that the need to satiate the demand for liquids during retrieval prevails over the conditioned aversion learned, suggesting, that thirst is a source of temporary variables dominating the aversive responses during CTA retrieval.


Asunto(s)
Sacarina , Gusto , Femenino , Ratas , Masculino , Animales , Gusto/fisiología , Sacarina/farmacología , Sed , Reacción de Prevención , Agua , Saciedad
19.
Neuropsychopharmacol Rep ; 43(1): 12-22, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36727594

RESUMEN

BACKGROUND: Although alcohol use disorder is a complex human pathology, the use of animal models represents an opportunity to study some aspects of this pathology. One of the most used paradigms to study the voluntary alcohol consumption in rodents is operant self-administration (OSA). AIMS: In order to facilitate the performance of this paradigm, we aim to describe some critical steps of OSA under a saccharin-fading procedure. MATERIAL & METHODS: We used 40 male Wistar rats to study the process of acquiring the operant response through a saccharin-fading procedure under a fixed ratio (FR1) schedule of reinforcement. Next, we analyze the alcohol introduction and concentration increase, the effect of an alcohol deprivation, and the analogy between this paradigm with the Drinking in the Dark-Multiple Scheduled Access paradigm. RESULTS: During alcohol concentration increase, animals reduced their lever presses in accordance with the increase in alcohol concentration. On the contrary, the consumption measured in g·kg-1 BW showed a great stability. The lever presses pattern within operant session changes with the introduction of different alcohol concentrations: at higher alcohol concentrations, animals tended to accumulate most of their presses in the initial period of the session. DISCUSSION: We show the utility of fading with low concentrations of saccharin and the evolution of the operant response through the different concentrations of alcohol. CONCLUSION: Taken together, our results aimed to dissect the acquisition and maintenance of OSA behavior as well as other related variables, to facilitate the understanding and performance of this paradigm.


Asunto(s)
Etanol , Sacarina , Animales , Humanos , Masculino , Ratas , Condicionamiento Operante/fisiología , Ratas Wistar , Sacarina/farmacología , Autoadministración
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 290: 122269, 2023 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-36566534

RESUMEN

The use of saccharin in food products attracts much attention as it involves the risk of lethal allergies and many protein aggregation diseases. However, its role in protein aggregation has not been explored to date. This study embodies the effect of artificial sweeteners on HEWL in the absence and presence of commonly available natural products such as curcumin and EGCG. Various techniques have been used to characterize the protein interaction, such as steady-state emission and time-resolved fluorescence, FTIR, gel electrophoresis, TEM, and molecular docking. Steady-state and time-resolved studies revealed the binding strength and concomitant effect of saccharin on HEWL protein. Kinetic measurements revealed that saccharin causes significant enhancement of HEWL aggregation with a considerable reduction in lag phase time i.e. from 37 hr to 08 hr. Whereas in the presence of natural products, the effect of saccharin on HEWL aggregation was significantly reduced specifically in the case of curcumin. The result obtained in the fluorescence experiment were also supported by the gel electrophoresis technique and morphological images taken by TEM. The rapid change in the secondary structure of the protein in the presence of saccharin was confirmed by the FTIR spectroscopy technique. This study is instrumental in understanding the effect of saccharin on protein aggregation and the role of commonly available natural products in curbing its effect.


Asunto(s)
Curcumina , Sacarina , Sacarina/farmacología , Sacarina/química , Edulcorantes/farmacología , Muramidasa/química , Simulación del Acoplamiento Molecular , Agregado de Proteínas , Curcumina/farmacología , Proteínas , Espectroscopía Infrarroja por Transformada de Fourier
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