The Effects of Fingolimod (FTY720) on Leukocyte Subset Circulation cannot be Behaviourally Conditioned in Rats

Suppression of immune functions can be elicited by behavioural conditioning using drugs such as cyclosporin A or rapamycin. Nevertheless, little is known about the underlying mechanisms and generalisability of this phenomenon. Against this background, the present study investigated whether the pharmacological properties of fingolimod (FTY720), an immunosuppressive drug widely applied to treat multiple sclerosis, can be conditioned in rats by means of taste-immune associative learning. For this purpose, a conditioned taste avoidance paradigm was used, pairing the presentation of a novel sweet drinking solution (saccharin or sucrose) as conditioned stimulus (CS) with therapeutically effective doses of FTY720 as unconditioned stimulus (US). Subsequent re-exposure to the CS at a later time point revealed that conditioning with FTY720 induced a mild conditioned taste avoidance only when saccharin was employed as CS. However, on an immunological level, neither re-exposure with saccharin nor sucrose altered blood immune cell subsets or splenic cytokine production. Despite the fact that intraperitonally administered FTY720 could be detected in brain regions known to mediate neuro-immune interactions, the present findings show that the physiological action of FTY720 is not inducible by mere taste-immune associative learning. Whether conditioning generalises across all small-molecule drugs with immunosuppressive properties still needs to be investigated with modified paradigms probably using distinct sensory CS. Moreover, these findings emphasize the need to further investigate the underlying mechanisms of conditioned immunomodulation to assess the generalisability and usability of associative learning protocols as supportive therapies in clinical contexts.

Obesogenic potentials of environmental artificial sweeteners with disturbances on both lipid metabolism and neural responses

Artificial sweeteners (ASs) entered the environments after application and emissions. Recent studies showed that some ASs had obesogenic risks. However, it remained unclear whether such risks are common and how they provoke such effects. Presently, the effects of 8 widely used ASs on lipid accumulation were measured in Caenorhabditis elegans. Potential mechanisms were explored with feeding and locomotion behavior, lipid metabolism and neural regulation. Results showed that acesulfame (ACE), aspartame (ASP), saccharin sodium (SOD), sucralose (SUC) and cyclamate (CYC) stimulated lipid accumulation at μg/L levels, showing obesogenic potentials. Behavior investigation showed that ACE, ASP, SOD, SUC and CYC biased more feeding in the energy intake aspect against the locomotion in the energy consumption one. Neotame (NEO), saccharin (SAC) and alitame (ALT) reduced the lipid accumulation without significant obesogenic potentials in the present study. However, all 8 ASs commonly disturbed enzymes (e.g., acetyl-CoA carboxylase) in lipogenesis and those (e.g., carnitine palmitoyl transferase) in lipolysis. In addition, ASs disturbed PPARγ (via expressions of nhr-49), TGF-β/DAF-7 (daf-7) and SREBP (sbp-1) pathways. Moreover, they also interfered neurotransmitters including serotonin (5-HT), dopamine (DA) and acetylcholine (ACh), with influences in Gsα (e.g., via expressions of gsα-1, ser-7), glutamate (e.g., mgl-1), and cGMP-dependent signaling pathways (e.g., egl-4). In summary, environmental ASs commonly disturbed neural regulation connecting behavior and lipid metabolism, and 5 out of 8 showed clear obesogenic potentials. ENVIRONMENTAL IMPLICATION: Artificial sweeteners (ASs) are become emerging pollutants after wide application and continuous emission. Recent studies showed that some environmental ASs had obesogenic risks. The present study employed Caenorhabditis elegans to explore the influences of 8 commonly used ASs on lipid metabolisms and also the underlying mechanisms. Five out of 8 ASs stimulated lipid accumulation at μg/L levels, and they biased energy intake against energy consumption. The other three ASs reduced the lipid accumulation. ASs commonly disturbed lipogenesis and lipolysis via PPARγ, TGF-β and SREBP pathways, and also influenced neurotransmitters with Gsα, glutamate and cGMP-dependent signaling pathways.

Design, synthesis, and docking study of saccharin N-triazolyl glycoconjugates

To achieve better-repurposed motifs, saccharin has been merged with biocompatible sugar molecules via a 1,2,3-triazole linker, and ten novel 1,2,3-triazole-appended saccharin glycoconjugates were developed in good yield by utilizing modular CuAAC click as regioselective triazole forming tool. The docking study indicated that the resulting hybrid molecules have an overall substantial interaction with the CAXII macromolecule. Moreover, the galactose triazolyl saccharin analogue 3h has a binding energy of -8.5 kcal/mol with 5 H-bonds, and xylosyl 1,2,3-triazolyl saccharin analogue 3d has a binding energy of -8.2 kcal/mol with 6 H-bond interactions and have exhibited the highest binding interaction with the macromolecule system.

COMPARISON OF GUT MICROBIOTA IN ALCOHOLIC AND METABOLIC-DYSFUNCION ASSOCIATED STEATOTIC LIVER DISEASE IN ANIMAL MODELS

BACKGROUND

Alcoholic liver disease (ALD) and metabolic-dysfunction associated steatotic liver disease (MASLD) are common, and gut microbiota (GM) is involved with both. Here we compared GM composition in animal models of MASLD and ALD to assess whether there are specific patterns for each disease.

METHODS

MASLD model- adult male Sprague Dawley rats, randomized into two groups: MASLD-control (n=10) fed a standard diet; MASLD-group (n=10) fed a high-fat-choline-deficient diet for 16 weeks. ALD model- adult male Wistar rats randomized: ALD-control (n=8) fed a standard diet and water+0.05% saccharin, ALD groups fed with sunflower seed and 10% ethanol+0.05% saccharin for 4 or 8 weeks (ALC4, n=8; ALC8, n=8). ALC4/8 on the last day received alcoholic binge (5g/kg of ethanol). Afterwards, animals were euthanized, and feces were collected for GM analysis.

RESULTS

Both experimental models induced typical histopathological features of the diseases. Alpha diversity was lower in MASLD compared with ALD (p<0.001), and structural pattern was different between them (P<0.001). Bacteroidetes (55.7%), Firmicutes (40.6%), and Proteobacteria (1.4%) were the most prevalent phyla in all samples, although differentially abundant among groups. ALC8 had a greater abundance of the phyla Cyanobacteria (5.3%) and Verrucomicrobiota (3.2%) in relation to the others. Differential abundance analysis identified Lactobacillaceae_unclassified, Lachnospiraceae_NK4A136_group, and Turicibacter associated with ALC4 and the Clostridia_UCG_014_ge and Gastranaerophilales_ge genera to ALC8.

CONCLUSION

In this study, we demonstrated that the structural pattern of the GM differs significantly between MASLD and ALD models. Studies are needed to characterize the microbiota and metabolome in both clinical conditions to find new therapeutic strategies.

BACKGROUND

•Changes in the composition of the intestinal microbiota are related to the development of alcoholic liver disease and metabolic-dysfunction associated steatotic liver disease.

BACKGROUND

•The diversity of the intestinal microbiota was lower in animals with MASLD compared to ALD.

BACKGROUND

•The structural pattern of the intestinal microbiota was significantly different among the experimental groups.

BACKGROUND

•Studies are needed to characterize the composition of the intestinal microbiota and metabolome to find new therapeutic strategies.

Catechol-O-Methyltransferase inhibition and alcohol use disorder: Evaluating the efficacy of tolcapone in ethanol-dependent rats

Alcohol Use Disorder (AUD) is a significant public health issue in the United States. It affects millions of individuals and their families and contributes to substantial societal and economic burdens. Despite the availability of some pharmacological treatments, there is still a pressing need to develop more effective therapeutic strategies to address the diverse range of symptoms and challenges associated with AUD. Catechol-O-methyltransferase (COMT) inhibition recently emerged as a promising new approach to treating AUD due to its potential to improve cognitive effects commonly associated with AUD. Tolcapone, an FDA-approved COMT inhibitor, has shown some promise for treating AUD; however, its ability to decrease drinking in ethanol-dependent rats has not been well-established. In this study, we evaluated the effects of tolcapone on operant, oral ethanol self-administration in non-dependent and dependent rats, and in rats that self-administered oral saccharin. To induce dependence, rats underwent the chronic intermittent exposure to vapor model, and their drinking levels were assessed during acute withdrawal from ethanol. Our results demonstrated that tolcapone attenuated responding for ethanol in dependent rats only, without affecting self-administration in non-dependent rats or rats self-administering saccharin. Moreover, we found that tolcapone was differentially effective in different estrous phases in female rats. These findings suggest that COMT inhibition, specifically using tolcapone, may be a valuable pharmacotherapy for treating AUD, particularly in individuals who are physically dependent on alcohol. Further research is needed to elucidate the precise mechanisms underlying the observed effects and to assess the potential of COMT inhibitors in a broader population of individuals with AUD.

Effects of combined exposure to ethanol and delta-9-tetrahydrocannabinol during adolescence on synaptic plasticity in the prefrontal cortex of Long Evans rats

Significant exposure to alcohol or cannabis during adolescence can induce lasting disruptions of neuronal signaling in brain regions that are later to mature, such as the medial prefrontal cortex (mPFC). Considerably less is known about the effects of alcohol and cannabis co-use, despite its common occurrence. Here, we used male and female Long-Evans rats to investigate the effects of early-life exposure to ethanol, delta-9-tetrahydrocannabinol (THC), or their combination on high frequency stimulation (HFS)-induced plasticity in the prelimbic region of the mPFC. Animals were injected daily from postnatal days 30-45 with vehicle or THC (escalating doses, 3-20 mg/kg) and allowed to drink vehicle (0.1% saccharin) or 10% ethanol immediately after each injection. In vitro brain slice electrophysiology was then used to record population responses of layer V neurons following HFS in layer II/III after 3-4 weeks of abstinence. We found that THC exposure reduced body weight gains observed in ad libitum fed rats, and reduced intake of saccharin and ethanol. Compared to controls, there was a significant reduction in HFS-induced long-term depression (LTD) in rats exposed to either drug alone, and an absence of LTD in rats exposed to the drug combination. Bath application of indiplon or AR-A014418, which enhance GABAA receptor function or inhibit glycogen synthase kinase 3β (GSK3β), respectively, suggested the effects of ethanol, THC or their combination were due in part to lasting adaptations in GABA and GSK3β signaling. These results suggest the potential for long-lasting adaptations in mPFC output following co-exposure to alcohol and THC.

An evaluation of hedonic responses in taste-potentiated odor aversion using the analysis of licking microstructure and orofacial reactivity

Two experiments examined the hedonic responses conditioned to odor cues in the phenomenon of taste-potentiated odor aversion. Experiment 1 analyzed the microstructure of licking behavior during voluntary consumption. A tasteless odor (amyl acetate) was delivered to rats either diluted in water or mixed with saccharin before being injected with LiCl. At test, subjects which had received the odor-taste compound during conditioning showed both lower odor consumption and lick cluster size, a result indicating an increased negative evaluation of the odor. Experiment 2 examined the orofacial reactions elicited by the odor as index of its hedonic impact. During conditioning, the rats were intraorally infused with either the odor alone or the odor-saccharin compound before being injected with LiCl. At test, they were infused with the odor and their orofacial responses video recorded. More aversive orofacial responses were elicited by the odor cue in rats that had compound conditioning, again a result indicating a strengthened negative hedonic reactivity compared to animals experiencing odor aversion conditioning alone. Taken together, these results indicate that taste-mediated potentiation of odor aversion conditioning impacts on the acquisition of conditioned hedonic reactions as well as consumption.

Cocaine-induced loss of LTD and social impairments are restored by fatty acid amide hydrolase inhibition

A single dose of cocaine abolishes endocannabinoid-mediated long-term depression (eCB-LTD) in the nucleus accumbens (NAc) within 24 h of administration. However, it is uncertain whether this altered neuroplasticity entails a behavioral deficit. As previously reported, after a single dose of cocaine (20 mg/kg), mice displayed impaired eCB-LTD in the NAc. Such cocaine-induced neuroplastic impairment was accompanied by an altered preference for saccharin and social interactions and a reduction in mRNA levels of the anandamide-catabolizing enzyme NAPE-PLD. The pharmacological increase of anandamide through the fatty acid amide hydrolase (FAAH) inhibitor URB597 (1 mg/kg) reversed the cocaine-induced loss of eCB-LTD in the NAc and restored normal social interaction in cocaine-exposed mice, but it did not affect saccharin preference. Overall, this research underlines the neuroplastic and behavioral alterations occurring after the initial use of cocaine and suggests a potential role for anandamide.

Adsorption of aqueous phase contaminants of emerging concern by activated carbon: Comparative fixed-bed column study and in situ regeneration methods

This work investigated the adsorption of five model contaminants of emerging concern (CECs) that are released daily in domestic effluents (caffeine, hydrochlorothiazide, saccharin, sulfamethoxazole and sucralose) onto two activated carbons (ACs), in fixed-bed column experiments with different aqueous matrices (ultrapure water, wastewater treatment plant (WWTP) effluent and WWTP effluent pretreated by reverse osmosis and photoperoxidation (reuse water)). The ACs were chemically similar, but AC1 had smaller particles (0.7-1.7 mm) and lower surface area (551 m2 g-1) than AC2 (1.2-2.4 mm and 716 m2 g-1). AC1 had a higher adsorption capacity (qads) for the CECs in the downflow mode. Overall, the qads values of the CECs followed the order: caffeine > sulfamethoxazole > hydrochlorothiazide = saccharin > sucralose. In the downflow mode, preferential pathways reduced the hydraulic retention time (HRT) of the fixed-bed column loaded with AC, which reduced the useful lifetime of column and the adsorption capacity. Nevertheless, the adsorption capacity and useful lifetime of the fixed-bed columns remained similar in the upflow mode (no preferential pathways were observed) regardless of the AC used. Since the HRTs were also found to be similar, it was evident that the crucial factor influencing the adsorption of the CECs was the HRT, which played a pivotal role in the overall process becoming evident. Compared to ultrapure water, use of the WWTP effluent reduced qads for all the CECs by up to 4.1 times, while reuse water reduced qads by up to 1.2 times. The AC1 could be in-situ regenerated using ethanol, with a global efficiency of 97.2 %. The results showed the importance of pretreatment techniques and optimization of the operational parameters, such as HRT, for enhancing the useful lifetime and qads of fixed-bed columns.

Switching from sucrose to saccharin: Extended successive negative contrast is not maintained by hedonic changes

Previous experiments found that acceptance of saccharin by rats was reduced if they had prior experience of sucrose or some other highly palatable solution. This reduction in saccharin consumption was particularly extended after a switch from sucrose. On the surface, this seems to correspond to a successive negative contrast (SNC) effect. This term was coined by C. F. Flaherty to describe the situation where consumption of a target solution is reduced by prior experience of a more valuable solution, typically a more concentrated version of the target solution. However, SNC effects are normally transient and assessed relative to a nonshifted control. Here, we confirm that the reduction in consumption seen when shifting from sucrose to saccharin is persistent and is seen relative to the traditional unshifted control. In addition, an analysis of licking microstructure showed that the shift from sucrose to saccharin suppressed the hedonic value of saccharin relative to controls, but this effect was less persistent than consumption suppression. Interestingly, a similar dissociation is observed in extinction of conditioned taste aversion (CTA): suppression of consumption produced by CTA is far more persistent than suppression of hedonic value. The comparison of results across procedures suggests that persistent SNC produced by a qualitative downshift from sucrose to saccharin appears different from quantitative downshifts in the concentration of a single solution, and qualitative downshift effects may involve CTA. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The impact of antimicrobial food additives and sweeteners on the growth and metabolite production of gut bacteria

Metabolic disorders caused by the imbalance of gut microbiota have been associated with the consumption of processed foods. Thus, this study aimed to evaluate the effects of antimicrobial food additives (benzoate, sorbate, nitrite, and bisulfite) and sweeteners (saccharin, stevia, sucralose, aspartame, and cyclamate) on the growth and metabolism of some gut and potentially probiotic bacterial species. The effects on the growth of Bifidobacterium longum, Enterococcus faecium, Lactobacillus acidophilus, and Lactococcus lactis subsp. lactis cultures were investigated using a turbidimetric test and by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). To evaluate the metabolic activity, the cultures were exposed to compounds with the highest antimicrobial activity, subjected to cultivation with inulin (1.5%), and analyzed by liquid chromatography for the production of short-chain fatty acids (acetate, propionate, and butyrate). The results showed that potassium sorbate (25 mg/mL), sodium bisulfite (0.7 mg/mL), sodium benzoate, and saccharin (5 mg/mL) presented greater antimicrobial activity against the studied species. L. lactis and L. acidophilus bacteria had reduced short-chain fatty acid production after exposure to saccharin and sorbate, and B. longum after exposure to sorbate, in comparison to controls (acetic acid reduction 1387 μg/mL and propionic 23 μg/mL p < 0.05).

Chronic administration of a norepinephrine antagonist prevents and partially reverses escalation of cocaine self-administration

Anxiety is a critical component of the development and maintenance of drug addiction; however, anti-anxiety medications such as benzodiazepines and beta-blockers (β-adrenergic receptor antagonists) are not used for the treatment of substance use disorder, except for the management of acute withdrawal syndrome. Preclinical studies have shown that beta-blockers may reduce stress-induced relapse; however, the effect of beta blockers on the escalation and maintenance of drug intake has not been tested. To address this issue, we chronically administered the β-adrenergic receptor antagonist propranolol during the escalation or maintenance of cocaine intake in a model of extended access (6 h) to cocaine self-administration (0.5 mg/kg). The behavioural specificity of propranolol was tested using a non-drug reward (saccharin). Daily administration of propranolol (15 mg/kg) prevented the development of escalation of cocaine self-administration and partially reversed self-administration after the establishment of escalation of intake. Moreover, propranolol dose-dependently decreased the motivation for cocaine tested under a progressive ratio schedule of reinforcement during the development of escalation and after maintenance. Finally, propranolol administration had no effect on the escalation and maintenance of saccharin self-administration. These results demonstrate that chronic treatment with propranolol provides therapeutic efficacy in reducing cocaine self-administration during the development and after the establishment of escalation of cocaine self-administration in an animal model relevant to cocaine use disorder. These results suggest that beta blockers should be further investigated as a target for medication development for the treatment of cocaine use disorder.

Impacts of maternal separation stress on ethanol-related responses, anxiety- and depressive-like behaviors in adolescent mice

The present work evaluated the consequences of chronic maternal separation (MS), an animal model of early-life stress, on ethanol intake and striatal Fos expression induced by ethanol consumption. Furthermore, we analyzed MS impacts on anxiety- and depressive-like behaviors and on locomotor and plasma corticosterone responses to intraperitoneal treatment with ethanol in adolescent mice. For that, male and female C57BL/6J mice were exposed or not to MS stress, for 3 h per day, from postnatal day (PND) 1 to 14, and submitted to behavioral tests from PND 28. In Experiment 1, MS and control groups of mice were submitted to an involuntary ethanol intake protocol, and striatal Fos expression following ethanol exposure was analyzed. In Experiment 2, mice behavior was assessed in elevated plus-maze, sucrose splash, saccharin preference, and open field tests. Locomotor and plasma corticosterone responses induced by a systemic dose of ethanol (1.75 g/kg) were also evaluated. Our results demonstrated that MS increased ethanol intake only in an acute manner and did not impact ethanol-induced Fos expression in the dorsal striatum and nucleus accumbens (NAc) core and shell subregions. MS did not change the parameters analyzed during elevated plus-maze, sucrose splash, preference for saccharin, and open field tests. MS did not affect locomotor activity following ethanol injection nor plasma corticosterone response to the drug. Thus, our data showed that MS transiently increased ethanol intake. However, early-life stress did not impact Fos, locomotor, or plasma corticosterone responses to the drug. In addition, MS did not affect anxiety- and depressive-like behaviors in adolescent mice.

Daily Variability in Urinary Artificial Sweeteners and Its Association with Oxidative Stress Biomarkers

Urinary artificial sweeteners (ASs) have been proved to be useful biomarkers for assessing their dietary intakes; however, it is unclear how well a spot urine sample may represent a longer-term exposure. Therefore, a longitudinal study was designed and six ASs and two oxidative stress biomarkers, namely, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA), were determined. Acesulfame (ACE) and saccharin (SAC) were detected in most urines with concentration ranges of Collapse

Key Words

• artificial sweeteners
• exposure assessment
• human biomonitoring
• oxidative stress biomarkers
• variability

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MESH Headings

• Humans
• 8-Hydroxy-2'-Deoxyguanosine
• Biomarkers/urine
• Deoxyguanosine
• Longitudinal Studies
• Oxidative Stress
• Saccharin
• Sweetening Agents

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Affiliation(s)

Yumeng Shi MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Hongkai Zhu MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Fei Wang Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China
Shucong Chen MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Ke Xu MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Lei Wang MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Hongwen Sun MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China

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Effects of voluntary adolescent intermittent alcohol exposure and social isolation on adult alcohol intake in male rats

Initiating alcohol use in adolescence significantly increases the likelihood of developing adult alcohol use disorder (AUD). However, it has been difficult to replicate adolescent alcohol exposure leading to increased adult alcohol intake across differing preclinical models. In the present study, differentially housed male rats (group vs. single cages) were used to determine the effects of voluntary intermittent exposure of saccharin-sweetened ethanol during adolescence on adult intake of unsweetened 20% ethanol. Adolescent male rats were assigned to group- or isolated-housing conditions and underwent an intermittent 2-bottle choice in adolescence (water only or water vs. 0.2% saccharin/20% ethanol), and again in adulthood (water vs. 20% ethanol). Intermittent 2-bottle choice sessions lasted for 24 h, and occurred three days per week, for five weeks. Rats were moved from group or isolated housing to single-housing cages for 2-bottle choice tests and returned to their original housing condition on off days. During adolescence, rats raised in isolated-housing conditions consumed significantly more sweetened ethanol than rats raised in group-housing conditions, an effect that was enhanced across repeated exposures. In adulthood, rats raised in isolated-housing conditions and exposed to sweetened ethanol during adolescence also consumed significantly higher levels of unsweetened 20% ethanol compared to group-housed rats. The effect was most pronounced over the first five re-exposure sessions. Housing conditions alone had little effect on adult ethanol intake. These preclinical results suggest that social isolation stress, combined with adolescent ethanol exposure, may play a key role in adult AUD risk.

Early-life low-calorie sweetener consumption disrupts glucose regulation, sugar-motivated behavior, and memory function in rats

Low-calorie sweetener (LCS) consumption in children has increased dramatically due to its widespread presence in the food environment and efforts to mitigate obesity through sugar replacement. However, mechanistic studies on the long-term impact of early-life LCS consumption on cognitive function and physiological processes are lacking. Here, we developed a rodent model to evaluate the effects of daily LCS consumption (acesulfame potassium, saccharin, or stevia) during adolescence on adult metabolic, behavioral, gut microbiome, and brain transcriptomic outcomes. Results reveal that habitual early-life LCS consumption impacts normal postoral glucose handling and impairs hippocampal-dependent memory in the absence of weight gain. Furthermore, adolescent LCS consumption yielded long-term reductions in lingual sweet taste receptor expression and brought about alterations in sugar-motivated appetitive and consummatory responses. While early-life LCS consumption did not produce robust changes in the gut microbiome, brain region-specific RNA-Seq analyses reveal LCS-induced changes in collagen- and synaptic signaling-related gene pathways in the hippocampus and nucleus accumbens, respectively, in a sex-dependent manner. Collectively, these results reveal that habitual early-life LCS consumption has long-lasting implications for glucoregulation, sugar-motivated behavior, and hippocampal-dependent memory in rats, which may be based in part on changes in nutrient transporter, sweet taste receptor, and central gene pathway expression.

New Saccharin Salt of Chlordiazepoxide: Structural and Physicochemical Examination

Since the formation of organic salts can improve the solubility, bioavailability, and stability of active pharmaceutical ingredients, the aim of this work was to prepare an organic salt of chlordiazepoxide with saccharin. To achieve this goal, the saccharin salt of chlordiazepoxide was obtained from a physical mixture of both components by grinding them with a small volume of solvent and by crystallizing them with complete evaporation of the solvent. The resulting salt was examined by methods such as Powder X-ray Diffraction (PXRD), Single Crystal X-ray Diffraction (SCXRD), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR), and Raman spectroscopy. The results of the studies proved that saccharin salt of chlordiazepoxide crystallizes in the orthorhombic Pbca space group with one chlordiazepoxide cation and one saccharin anion in the asymmetric unit. In the crystal of the title compound, the chlordiazepoxide cation and the saccharin anion interact through strong N–H···O hydrogen bonds and weak C–H···O hydrogen bonds. The disappearance of the N–H band in the FT-IR spectrum of saccharin may indicate a shift of this proton towards chlordiazepoxide, while the disappearance of the aromatic bond band in the chlordiazepoxide ring in the Raman spectrum may suggest the formation of intermolecular hydrogen bonds between chlordiazepoxide molecules. The melting point of the salts differs from that of the starting compounds. Thermal decomposition of the salt begins above 200 °C and shows at least two overlapping stages of mass loss. In summary, the results of the research showed that the crystalline salt of the saccharin and chlordiazepoxide can be obtained by various methods: grinding with the addition of acetonitrile and crystallization from acetonitrile or a mixture of methanol with methylene chloride.

High-sucrose diet exposure is associated with selective and reversible alterations in the rat peripheral taste system

Elevated sugar consumption is associated with an increased risk for metabolic diseases. Whereas evidence from humans, rodents, and insects suggests that dietary sucrose modifies sweet taste sensation, understanding of peripheral nerve or taste bud alterations is sparse. To address this, male rats were given access to 30% liquid sucrose for 4 weeks (sucrose rats). Neurophysiological responses of the chorda tympani (CT) nerve to lingual stimulation with sugars, other taste qualities, touch, and cold were then compared with controls (access to water only). Morphological and immunohistochemical analyses of fungiform papillae and taste buds were also conducted. Sucrose rats had substantially decreased CT responses to 0.15-2.0 M sucrose compared with controls. In contrast, effects were not observed for glucose, fructose, maltose, Na saccharin, NaCl, organic acid, or umami, touch, or cold stimuli. Whereas taste bud number, size, and innervation volume were unaffected, the number of PLCβ2+ taste bud cells in the fungiform papilla was reduced in sucrose rats. Notably, the replacement of sucrose with water resulted in a complete recovery of all phenotypes over 4 weeks. The work reveals the selective and modality-specific effects of sucrose consumption on peripheral taste nerve responses and taste bud cells, with implications for nutrition and metabolic disease risk. VIDEO ABSTRACT.

Systemic administration of racemic baclofen reduces both acquisition and maintenance of alcohol consumption in male and female mice

Baclofen is a GABAB receptor agonist with proposed use as a treatment for alcohol use disorder (AUD). In preclinical studies, racemic baclofen decreases alcohol consumption in both mice and rats; however, there is a significant disparity in the efficacy of the drug across species. We previously demonstrated that baclofen is enantioselective, with the racemic enantiomer successfully reducing binge-like alcohol consumption during Drinking-in-the-Dark (DID) in C57BL/6J (B6) mice, as well as 24-h consumption during two-bottle choice (2BC) preference drinking in replicate 1 High Alcohol Preferring (HAP) mice. Here we extend these findings by investigating the effects of racemic baclofen on the acquisition and maintenance of alcohol consumption, locomotor activity, and saccharin drinking in two different mouse genotypes and drinking paradigms. Adult male and female B6 mice were allowed free access to 20% (v/v) alcohol for 2 h daily in a 14-day DID procedure. Adult male and female replicate 2 HAP (HAP2) mice were allowed 24-h access to 10% (v/v) alcohol versus tap water in a 2BC procedure for 14 days. Systemic injections of baclofen (0.0 or 3.0 mg/kg) were given 3 h into the dark cycle on days 1-5 in alcohol acquisition experiments and days 6-10 in alcohol maintenance experiments. We found that racemic baclofen significantly reduces acquisition of DID and 2BC alcohol drinking in male and female B6 and HAP2 mice, whereas it only significantly reduces the maintenance of DID alcohol intake in B6 mice. Racemic baclofen did not alter home cage locomotor activity but did alter saccharin intake, suggesting it may have nonspecific effects. The current data add to literature suggesting that smaller doses of racemic baclofen may be an effective treatment of AUD. Future work should focus on the longitudinal efficacy of racemic baclofen in high-drinking mouse genotypes to further investigate whether it is effective for those with a genetic predisposition to AUD.

Benefits of nasal saline treatment in acute rhinosinusitis: Systematic review and meta-analysis

BACKGROUND

Although nasal saline treatments are widely used in treating acute rhinosinusitis (ARS), the evidence in adult patients is inconclusive. Our objective was to assess the add-on benefits of saline treatment in adults with ARS.

METHODS

Literature searches were performed (updated May 9, 2021). Randomized, controlled trials studying the effects of nasal saline treatment in adults with ARS were included. Data were pooled for meta-analysis. Outcomes were composite symptoms score (CSS), disease-specific quality-of-life (DS-QoL) score, individual symptom score, endoscopy score, saccharin transit time, cure rate, days to resolution, and adverse events.

RESULTS

Eleven studies (718 patients) were included in our investigation. Nasal discharge was the only symptom improved (standardized mean difference [SMD], -0.36; 95% confidence interval [CI], -0.66 to -0.05]. Saline as an add-on treatment brought no benefit to CSS and DS-QoL score at both time-points (3-10 days and at the end of the study). Other outcomes also showed no benefits with use of saline, including endoscopy score, saccharin transit time, cure rate, days to resolution, and adverse events. Subgroup analyses showed improvement in viral ARS patients for CSS (SMD, -0.60; 95% CI, -1.12 to -0.08) and DS-QoL score (mean difference, -15.90; 95% CI, -31.78 to -0.02), and also in patients using high-volume saline (SMD, -0.42; 95% CI, -0.78 to -0.06).

CONCLUSION

Nasal saline as an add-on treatment improved rhinorrhea. There was no improvement in CSS and DS-QoL, except among the subgroup of viral ARS patients using high-volume saline. There were no differences in adverse events between the saline and non-saline treatments.

Artificial Sweeteners in Breast Milk: A Clinical Investigation with a Kinetic Perspective

Artificial sweeteners (ASs) are calorie-free chemical substances used instead of sugar to sweeten foods and drinks. Pregnant women with obesity or diabetes are often recommended to substitute sugary products with ASs to prevent an increase in body weight. However, some recent controversy surrounding ASs relates to concerns about the risk of obesity caused by a variety of metabolic changes, both in the mother and the offspring. This study addressed these concerns and investigated the biodistribution of ASs in plasma and breast milk of lactating women to clarify whether ASs can transfer from mother to offspring through breast milk. We recruited 49 lactating women who were provided with a beverage containing four different ASs (acesulfame-potassium, saccharin, cyclamate, and sucralose). Blood and breast milk samples were collected before and up to six hours after consumption. The women were categorized: BMI < 25 (n = 20), BMI > 27 (n = 21) and type 1 diabetes (n = 8). We found that all four ASs were present in maternal plasma and breast milk. The time-to-peak was 30−120 min in plasma and 240−300 min in breast milk. Area under the curve (AUC) ratios in breast milk were 88.9% for acesulfame-potassium, 38.9% for saccharin, and 1.9% for cyclamate. We observed no differences in ASs distributions between the groups.

Effect of saccharin, a non-nutritive sweeteners, on insulin and blood glucose levels in healthy young men: A crossover trial

BACKGROUND AND AIMS

Artificial sweeteners used instead of sugar were considered as the best alternatives that have no endocrine effects. However, it has recently been suggested that artificial sweeteners may cause impaired metabolic parameters. The hypothesis of the study was there is an association between acute saccharin consumption and both glycemia and insulin response in young healthy adult men.

METHODS

9 healthy adult males were included in this study. This study randomly provided participants with preloads as (a)300 ml of water, or 300 ml of water sweetened with (b)75 g of sucrose, (c)240 mg of saccharine (adjusted to the sweetness of 75 g of sucrose) 1 h before a standard breakfast.

RESULTS

Compared to mean blood glucose and serum insulin after test drinks consumption, there was only one difference between sucrose and saccharin trials in the 15th minute (117.0 ± 18.70, 95.4 ± 5.64 mg/dl respectively, p < 0.05). At the 60th minute, insulin secretion (0.80 ± 0.27 pg/dl) after the sucrose trial was found significantly higher than the saccharin trial (0.53 ± 0.09 pg/dl) and water (0.49 ± 0.06 pg/dl) (p < 0.05). Although at all intervals (except 90th minute), the mean insulin is higher after the saccharin trial compared to the water trial, these were non-statistically significant differences (p > 0.05).

CONCLUSIONS

Consequently, it was determined that saccharin had no glycemic effect. However, for the effect on serum insulin to be clarified, the long-term effects should be investigated.

Low-Frequency Vibrational Spectroscopy Characteristic of Pharmaceutical Carbamazepine Co-Crystals with Nicotinamide and Saccharin

The pharmaceutical co-crystal has attracted increasing interest due to the improvement of physicochemical properties of active pharmaceutical ingredients. The characterization of pharmaceutical co-crystal is an integral part of the pharmaceutical field. In this paper, the low-frequency vibrational properties for carbamazepine co-crystals with nicotinamide and saccharin (CBZ-NIC and CBZ-SAC) have been characterized by combining the THz spectroscopy with low-wavenumber Raman spectroscopy. The experiment results show that, compared with the individual constituents, CBZ-NIC and CBZ-SAC co-crystals not only have different characteristic absorption peaks in the 0.3-2.5 THz region, but also have significant low-wavenumber Raman characteristic peaks in 0–100 cm⁻¹. Density functional theory was performed to simulate the terahertz and low-wavenumber Raman spectra of the two co-crystals, where the calculation agreed well with the measured vibrational peak positions. The vibrational modes of CBZ-NIC and CBZ-SAC co-crystals were assigned through comparing theoretical results with the experimental spectra. Meanwhile, the low-frequency infrared and/or Raman active of characteristic peaks for such co-crystals were discussed. The results indicate the combination of THz spectroscopy and low-wavenumber Raman spectroscopy can provide more comprehensive low-frequency vibrational information for pharmaceutical co-crystals, such as collective vibration and skeleton vibration, which could play an important role in pharmaceutical science.

Degradation of saccharin by UV/H2O2 and UV/PS processes: A comparative study

Artificial sweeteners have raised emerging concern due to their potential threats to human health, which were frequently detected in aquatic environment with median concentrations. Although current researches have widely reported that ultraviolet light-activated persulfate process (UV/PS) was superior to UV/H₂O₂ process for the degradation of refractory organic contaminants, UV/H₂O₂ process presented a more satisfactory saccharin (SAC) removal efficiency than UV/PS process, completely degraded 20 mg/L SAC within 45 min. Hence, quenching and probe experiments were employed to investigate the difference between hydroxyl radical (OH)- and sulfate radical (SO₄^-)-mediated oxidation mechanisms, which revealed the higher reactivity of OH (1.37-1.56 × 10⁹ M^-1 s^-1) toward SAC than SO₄^- (3.84-4.13 × 10⁸ M^-1 s^-1). A combination of density functional theory calculation and transformation products identification disclosed that OH preferred to attack the benzene ring of SAC via hydrogen atom transfer pathway, whereas SO₄^- oxidation was conducive to the cleavage of -C-NH₂ bond. Increasing oxidant concentration significantly accelerated SAC degradation in both processes, while UV/H₂O₂ process consumed lower electrical energy with respect to UV/PS process. Additionally, UV/H₂O₂ system presented excellent adaptability and stability under various water matrices parameters (e.g. pH, anions and humic acid). While both UV/H₂O₂ and UV/PS processes promoted the generation of disinfection by-products (DBPs) during subsequent chlorination, and prolonging pretreatment time posed positive effect on reducing the formation of DBPs. Overall, the results clearly demonstrate the high efficiency, economy and practicality of UV/H₂O₂ process in the remediation of SAC-contaminated water.

Synergic Effects in the Activation of the Sweet Receptor GPCR Heterodimer for Various Sweeteners Predicted Using Molecular Metadynamics Simulations

The sweet taste is elicited by activation of the TAS1R2/1R3 heterodimer G protein-coupled receptor. This is a therapeutic target for treatment of obesity and metabolic dysfunctions. Sweetener blends provide attractive strategies to lower the sugar level while preserving the attractive taste of food. To understand the synergic effect of various sweetener blend combinations of artificial and natural sweeteners, we carried out our molecular dynamics studies using predicted structures of the TAS1R2/1R3 heterodimer and predicted structures for the sweeteners. We used as a measure of activation the intracellular ionic lock distance between transmembrane helices 3 and 6 of TAS1R3. We find that full synergic combinations [rebaudioside A (Reb-A)/acesulfame K and Reb-A/sucralose] and partial synergic combinations (sucralose/acesulfame K) show significantly more negative changes in the free energy compared to single-ligand cases, while a pair known to be suppressive (saccharin and acesulfame K) shows significantly less changes than for the single-ligand case. This study provides an atomistic understanding of the mechanism for synergy and identifies new combinations of sweeteners to reduce the caloric content for treating diseases.

Saccharin Provides Protection and Activates Defense Mechanisms in Wheat Against the Hemibiotrophic Pathogen Zymoseptoria tritici

Plant resistance inducers are among the most promising alternatives to develop sustainable crop protection. Here, we examined the ability of saccharin, a metabolite derived from probenazole, to protect wheat against Zymoseptoria tritici, the most frequently occurring and damaging foliar pathogen on this crop. The experiments were performed in the greenhouse by treating seedlings of the wheat cultivar 'Alixan' with 15 mM of saccharin 2 days before challenge inoculation with the Z. tritici pathogenic strain T02596. Foliar application of saccharin resulted in 77% lower disease severity than in nontreated control plants. In vitro and in planta assays showed that saccharin did not exhibit any direct antifungal effect on spore germination or hyphal growth. Molecular investigations from 2 to 7 days posttreatment (dpt) revealed that saccharin treatment upregulates the expression of genes encoding for lipoxygenase (LOX) at all sampled time points and pathogenesis-related protein 1 (PR1) at 7 dpt, in both noninfectious and infectious contexts, as well as peroxidase (POX2) in noninfectious conditions. However, saccharin did not induce significant change in the expression of PAL gene encoding for phenylalanine ammonia-lyase. Our findings report for the first time the potential of saccharin to confer protection in wheat against Z. tritici through an elicitation and priming of LOX and PR gene-related defense pathways. Additional investigations would provide a better deciphering of defense mechanisms activated by this molecule in wheat against Z. tritici.

Aqueous degradation of artificial sweeteners saccharin and neotame by metal organic framework material

The artificial sweeteners (ASs) saccharin (SAC) and neotame (NEO) are widely used across the globe and are considered as emerging contaminants in surface, ground, and drinking waters. To degrade SAC and NEO, the metal organic framework material Co-based bio-MOF-11 was prepared by hydrothermal reaction and used with peroxymonosulfate (PMS) activator. The effects of the initial concentration of SAC and NEO, bio-MOF-11-Co dosage, PMS concentration, initial pH, temperature, and competitive anions were determined. The results revealed that bio-MOF-11-Co effectively catalyzed the degradation of SAC and NEO and possessed good stability and recycling efficiency. The degradation reaction was effective from pH 3.6-9.8 and followed quasi-first-order kinetics with degradation rate constants of 0.001-0.013 min^-1 for SAC and 0.03-0.52 min^-1 for NEO. Increased temperature was conducive to the degradation of both artificial sweeteners. The presence of Cl^- inhibited the degradation of SAC and NEO, while the presence of CO₃^2- promoted their degradation. Electron paramagnetic resonance (EPR) and free radical quenching demonstrated that the primary free radicals were sulfate radicals ( [Formula: see text] ) and hydroxyl radicals (HO). The change of cobalt oxidation state and electron transfer in bio-MOF-11-Co mainly induces the production of [Formula: see text] . A plausible mechanism for degradation is [Formula: see text] and HO attack on CS bonds, NS bonds, and benzene rings.

Terahertz spectroscopic characterizations and DFT calculations of indomethacin cocrystals with nicotinamide and saccharin

Co-crystallization is an effective strategy to improve the drug properties such as solubility and stability. However, its thermodynamic backgrounds, especially lattice vibration, haven't been fully understood. In this work, indomethacin (IND) cocrystals formed with nicotinamide (NIC) and saccharin (SAC) are successfully characterized by using terahertz spectroscopy. DFT calculations at PBE-D3 level with and without constrained unit cell are performed to predict the absorption peaks at spectral range. The results suggest that the DFT calculations with constrained unit cell achieve a better agreement with experimental observations. Based on the optimized geometries and calculated phonons, the thermodynamic contributions from lattice vibrations to cocrystal formations are further evaluated. The findings reveal that the vibrational energy plays a comparable role with electronic energy, but has an opposite impact on these two cocrystal formations.

Distracting stimuli evoke ventral tegmental area responses in rats during ongoing saccharin consumption

Disruptions in attention, salience and increased distractibility are implicated in multiple psychiatric conditions. The ventral tegmental area (VTA) is a potential site for converging information about external stimuli and internal states to be integrated and guide adaptive behaviours. Given the dual role of dopamine signals in both driving ongoing behaviours (e.g., feeding) and monitoring salient environmental stimuli, understanding the interaction between these functions is crucial. Here, we investigate VTA neuronal activity during distraction from ongoing feeding. We developed a task to assess distraction exploiting self-paced licking in rats. Rats trained to lick for saccharin were given a distraction test, in which three consecutive licks within 1 s triggered a random distractor (e.g. light and tone stimulus). On each trial they were quantified as distracted or not based on the length of their pauses in licking behaviour. We expressed GCaMP6s in VTA neurons and used fibre photometry to record calcium fluctuations during this task as a proxy for neuronal activity. Distractor stimuli caused rats to interrupt their consumption of saccharin, a behavioural effect which quickly habituated with repeat testing. VTA neural activity showed consistent increases to distractor presentations and, furthermore, these responses were greater on distracted trials compared to non-distracted trials. Interestingly, neural responses show a slower habituation than behaviour with consistent VTA responses seen to distractors even after they are no longer distracting. These data highlight the complex role of the VTA in maintaining ongoing appetitive and consummatory behaviours while also monitoring the environment for salient stimuli.

The effect of economy type on heroin and saccharin essential value

According to behavioral economics, reinforcer value should be lower in an open economy than in a closed economy. An animal model was used to determine how economy type affected the value of heroin and saccharin. In a first phase, separate groups of rats worked for heroin or saccharin. The price of these reinforcers increased over sessions. For rats in the open heroin or open saccharin economies, the work period of each session was followed by a postwork period where a cheaper source of heroin or saccharin was available for three hours. For rats in the closed economies, the work period was their only opportunity to obtain the reinforcer. Rats in the open saccharin economy worked less hard to defend consumption of saccharin as price increased than rats in the closed saccharin economy. That is, opening the saccharin economy reduced its essential value. In contrast, economy type had no effect on heroin's essential value. In a second phase, rats were allowed to choose between heroin and saccharin. The majority of rats strongly preferred saccharin over heroin regardless of economy type. The finding that economy type changed the essential value of saccharin, but not heroin, adds to previous findings suggesting that the value of drug reinforcers is unaffected by future drug availability. The difference in effect of economy type on drug versus nondrug reinforcers could be relevant to addiction. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Postmeal Optogenetic Inhibition of Dorsal or Ventral Hippocampal Pyramidal Neurons Increases Future Intake

Memory of a recently eaten meal can serve as a powerful mechanism for controlling future eating behavior because it provides a record of intake that likely outlasts most physiological signals generated by the meal. In support, impairing the encoding of a meal in humans increases the amount ingested at the next eating episode. However, the brain regions that mediate the inhibitory effects of memory on future intake are unknown. In the present study, we tested the hypothesis that dorsal hippocampal (dHC) and ventral hippocampal (vHC) glutamatergic pyramidal neurons play a critical role in the inhibition of energy intake during the postprandial period by optogenetically inhibiting these neurons at specific times relative to a meal. Male Sprague Dawley rats were given viral vectors containing CaMKIIα-eArchT3.0-eYFP or CaMKIIα-GFP and fiber optic probes into dHC of one hemisphere and vHC of the other. Compared to intake on a day in which illumination was not given, inhibition of dHC or vHC glutamatergic neurons after the end of a chow, sucrose, or saccharin meal accelerated the onset of the next meal and increased the amount consumed during that next meal when the neurons were no longer inhibited. Inhibition given during a meal did not affect the amount consumed during that meal or the next one but did hasten meal initiation. These data show that dHC and vHC glutamatergic neuronal activity during the postprandial period is critical for limiting subsequent ingestion and suggest that these neurons inhibit future intake by consolidating the memory of the preceding meal.

Effects of oral isotretinoin therapy on the nasal cavities

Introduction

Isotretinoin (13 cis-retinoic acid) is the most effective treatment for acne vulgaris and is the only treatment option that can provide either remission or a permanent cure.

Objective

The aim of this study was to use both subjective and objective methods to assess the nasal complaints of patients with severe acne who received oral isotretinoin therapy.

Methods

Fifty-four subjects were enrolled in the study. All the subjects were assessed with subjective (NOSE and VAS questionnaires) and objective (rhinomanometry and saccharine) tests to determine the severity of their nasal complaints.

Results

The mean severity scores (min: 0; max: 100) for nasal dryness/crusting and epistaxis were 0.47 ± 1.48 (0–5); 0.35 ± 1.30 (0–5) at admission, 3.57 ± 4.45 (0–10); 2.26 ± 4.71 (0–20) at the first month, and 4.28 ± 6 (0–20); 2.26 ± 4.71 (0–20) at the third month of the treatment respectively. Total nasal resistance of 0.195 ± 0.079 (0.12–0.56) Pa/cm³/s at admission, 0.21 ± 0.084 (0.12–0.54) Pa/cm³/s at the first month, and 0.216 ± 0.081 (0.14–0.54) Pa/cm³/s at the third month.

Conclusion

Oral isotretinoin therapy can cause the complaint of nasal obstruction. In addition, nasal complaints, such as dryness/crusting and epistaxis, significantly increase in patients during the therapy schedule.

Incentive contrast effects regulate responding to a flavor presented in compound with a saccharin unconditioned stimulus in rats

A flavor conditioned stimulus (conditional stimulus; CS) presented in simultaneous compound with a sweet-tasting unconditioned stimulus (US) acquires a certain sweetness and/or hedonic value. The present study examined whether responding to the flavor CS is influenced by postconditioning changes in the strength of the sweet US representation. In each experiment, rats were exposed to presentations of each of 2 flavors, A and B, in simultaneous compound with a 0.4% saccharin solution, and then tested with presentations of CS A in water. Experiments 1 and 2 showed that responding to CS A depended on its pairing with saccharin and increased with the training-to-test interval. Experiment 3 showed that a progressive reduction in the saccharin concentration of the trained compounds led to an increase in responding to CS A when tested in the absence of saccharin. Experiments 4 and 5 showed that, after a 7-day training-to-test delay, responding to CS A decreased following pretest exposure to a strong saccharin solution, and increased following pretest exposure to a very weak saccharin solution. These findings are taken to imply that incentive contrast effects regulate responding to a flavor CS. Hence, responding to the flavor CS increases with the training-to-test interval as the representation of the sweet US decays; decreases following pretest exposure to very sweet solutions as these reinstate the decayed sweet US representation (negative contrast); and increases following pretest exposure to weakly sweet solutions as these are perceived as less attractive than the CS itself (positive contrast). (PsycINFO Database Record

Pharmacological characterization of the nociceptin/orphanin FQ receptor on ethanol-mediated motivational effects in infant and adolescent rats

Activation of nociceptin/orphanin FQ (NOP) receptors attenuates ethanol drinking and prevents relapse in adult rodents. In younger rodents (i.e., infant rats), activation of NOP receptors blocks ethanol-induced locomotor activation but does not attenuate ethanol intake. The aim of the present study was to extend the analysis of NOP modulation of ethanol's effects during early ontogeny. Aversive and anxiolytic effects of ethanol were measured in infant and adolescent rats via conditioned taste aversion and the light-dark box test; whereas ethanol-induced locomotor activity and ethanol intake was measured in adolescents only. Before these tests, infant rats were treated with the natural ligand of NOP receptors, nociceptin (0.0, 0.5 or 1.0 μg) and adolescent rats were treated with the specific agonist Ro 64-6198 (0.0, 0.1 or 0.3 mg/kg). The activation of NOP receptors attenuated ethanol-induced anxiolysis in adolescents only, and had no effect on ethanol's aversive effects. Administration of Ro 64-6198 blocked ethanol-induced locomotor activation but did not modify ethanol intake patterns. The attenuation of ethanol stimulating and anxiolytic effect by activation of NOP receptors indicates a modulatory role of this receptor on ethanol effects, which is expressed early in ontogeny.

Effect of combined doses of Δ(9)-tetrahydrocannabinol (THC) and cannabidiolic acid (CBDA) on acute and anticipatory nausea using rat (Sprague- Dawley) models of conditioned gaping

RATIONALE

Δ(9)-Tetrahydrocannabinol (THC) and cannabidiolic acid (CBDA) found in cannabis both reduce the distressing symptom of nausea, but their combined effects are not understood.

OBJECTIVE

The potential of combined doses of THC and CBDA to reduce acute nausea and anticipatory nausea in rodent models was assessed.

MATERIALS AND METHODS

For acute nausea, the potential of cannabinoid pretreatment(s) to reduce LiCl-induced nausea paired with saccharin was evaluated in a subsequent drug free taste reactivity test, followed by a taste avoidance test. For anticipatory nausea, the potential of the cannabinoid pretreatment(s) to reduce the expression of LiCl-induced contextually elicited conditioned gaping was evaluated.

RESULTS

Combined subthreshold doses of THC (0.01 and 0.1 mg/kg) and CBDA (0.01 and 0.1 μg/kg) reduced acute nausea. Higher doses of THC (1.0, 10 mg/kg) or CBDA (1.0, 10 μg/kg) alone, as well as these combined doses also reduced acute nausea. THC (10 mg/kg) interfered with conditioned taste avoidance, an effect attenuated by CBDA (10 μg/kg). On the other hand, combined subthreshold doses of THC (0.01 and 0.1 mg/kg) and CBDA (0.01 and 0.1 μg/kg) did not suppress contextually elicited conditioned gaping in a test for anticipatory nausea. However, higher doses of THC (1.0, 10 mg/kg) or CBDA (1.0, 10 μg/kg) alone, as well as these combined doses, also reduced anticipatory nausea. Only at the highest dose (10 mg/kg) did THC impair locomotor activity, but CBDA did not at any dose.

CONCLUSIONS

Combined subthreshold doses of THC:CBDA are particularly effective as a treatment for acute nausea. At higher doses, CBDA may attenuate THC-induced interference with learning.

The basolateral nucleus of the amygdala mediates caloric sugar preference over a non-caloric sweetener in mice

Neurobiological and genetic mechanisms underlying increased intake of and preference for nutritive sugars over non-nutritive sweeteners are not fully understood. We examined the roles of subnuclei of the amygdala in the shift in preference for a nutritive sugar. Food-deprived mice alternately received caloric sucrose (1.0 M) on odd-numbered training days and a non-caloric artificial sweetener (2.5 mM saccharin) on even-numbered training days. During training, mice with sham lesions of the basolateral (BLA) or central (CeA) nucleus of the amygdala increased their intake of 1.0 M sucrose, but not saccharin. Trained mice with sham lesions showed a significant shift in preference toward less concentrated sucrose (0.075 M) over the saccharin in a two-bottle choice test, although the mice showed an equivalent preference for these sweeteners before training. No increased intake of or preference for sucrose before and after the alternating training was observed in non-food-deprived mice. Excitotoxic lesions centered in the BLA impaired the increase in 1.0M sucrose intake and shift in preference toward 0.075 M sucrose over saccharin. Microlesions with iontophoretic excitotoxin injections into the CeA did not block the training-dependent changes. These results suggest that food-deprived animals selectively shift their preference for a caloric sugar over a non-caloric sweetener through the alternate consumption of caloric and non-caloric sweet substances. The present data also suggest that the BLA, but not CeA, plays a role in the selective shift in sweetener preference.

Assessment of nasal airway resistances and nasal mucociliary activities of patients with unilateral chronic otitis media by acoustic rhinometry and saccharin test

CONCLUSIONS

A significant increase was determined in nasal airway resistance of the pathological side of the patients with unilateral chronic otitis media (COM) compared with the non-pathological side and the patients with normal ears. Based upon this result, nasal pathologies should also be considered during the diagnosis and treatment stages of patients with COM.

OBJECTIVES

We aimed to investigate whether there was a causal relationship between nasal pathologies causing eustachian tube dysfunction and COM.

METHODS

Thirty patients were randomly selected from among patients who presented due to hearing loss and ear discharge, and 30 healthy volunteers were randomly selected as the control group. Acoustic rhinometry and saccharin tests were performed in all of the subjects. Test results were recorded for both the groups and statistical analysis was performed.

RESULTS

A statistically significant correlation was found between the pathological results and COM side in acoustic rhinometry (p < 0.01). The prevalence of pathology in the right side of the nasal cavity was found to be higher in the group with perforation in the right ear (73.7%) and in the left side of the nasal cavity was also found to be higher in the group with perforation in the left ear (54.5%).

[Influence of smoking on the nasal mucosa mucociliary transport]

The aim of the study was to compare mucociliary transport between healthy smokers and nonsmokers and to evaluate the influence of the duration of smoking, number of cigarettes per day and age on mucociliary function. The study included 176 subjects divided into two groups. One group consisted of 96 smokers and the other group of 80 nonsmokers. The saccharin test that measures mucociliary transport was performed on all study subjects. Analysis of test results showed a statistically significant difference in mucociliary transport between smokers older than average and the younger ones (t=2.58; df=22; P=0.01 7). Damage to the mucociliary transport was more severe in older smokers. A statistically significant difference in mucociliary transport was also found in smokers with a longer than average duration of smoking habit (t=3.362; df=22; P=0.003). There was no statistically significantly slower mucociliary transport according to the number of cigarettes per day and age at starting smoking. In conclusion, mucociliary transport was statistically slower in smokers that were older and had a longer smoking history as compared with younger smokers having smoking for a shorter time. Smoking has an important effect on mucociliary transport of the nasal mucosa.

"Jello® shots" and cocktails as ethanol vehicles: parametric studies with high- and low-saccharin-consuming rats

Naïve humans and rats voluntarily consume little ethanol at concentrations above ~6% due to its aversive flavor. Developing procedures that boost intake of ethanol or ethanol-paired flavors facilitates research on neural mechanisms of ethanol-associated behaviors and helps identify variables that modulate ethanol intake outside of the lab. The present study explored the impact on consumption of ethanol and ethanol-paired flavors of nutritionally significant parametric variations: ethanol vehicle (gelatin or solution, with or without polycose); ethanol concentration (4% or 10%); and feeding status (chow deprived or ad lib.) during flavor conditioning and flavor preference testing. Individual differences were modeled by testing rats of lines selectively bred for high (HiS) or low (LoS) saccharin intake. A previously reported preference for ethanol-paired flavors was replicated when ethanol had been drunk during conditioning. However, indifference or aversion to ethanol-paired flavors generally obtained when ethanol had been eaten in gelatin during conditioning, regardless of ethanol concentration, feeding status, or caloric value of the vehicle. Modest sex and line variations occurred. Engaging different behavioral systems when eating gelatin, rather than drinking solution, may account for these findings. Implications for parameter selection in future neurobiological research and for understanding conditions that influence ethanol intake outside of the lab are discussed.

Effect of systemic isotretinoin therapy on mucociliary clearance and nasal surface mucosa in acne patients

BACKGROUND

Currently, there are no studies investigating the topical or systemic effects of retinoids on human nasal mucosa. We aimed to investigate the effect of systemic isotretinoin therapy on mucociliary transport and nasal surface mucosa using the saccharine test (ST) and nasal cytology techniques.

METHODS

A total of 30 patients with severe or moderate acne were enrolled in this study. The median prescribed dose of isotretinoin was 0.75 mg per kg per day. Clinical and biochemical examinations were carried out periodically. The ST and nasal cytology were performed before treatment and during the third month of therapy.

RESULTS

Of the 30 patients who initially agreed to participate in the research, 21 completed the study (18 female and 3 male, mean ± standard deviation (SD) aged 20.9 ± 4.7 years, range 15-32 years). There was a significant difference between the mucociliary clearance time for subjects in the pre- and post-treatment periods (173.8 ± 89.2 seconds vs 245.2 ± 191.6 seconds, respectively; P=.009). Cytological examination revealed that the squamous cell ratio was significantly lower and the reactive changes of the respiratory epithelium were significantly higher 3 months after isotretinoin therapy than before therapy (P=.010, P=.002, respectively). There were mild signs of inflammation according to the number of neutrophilic leukocytes (8.3% vs 26.6%, P=.06) after 3 months of isotretinoin therapy.

CONCLUSION

Systemic isotretinoin alters the mucociliary transport, decreases the squamous cell ratio, increases the reactive changes in the respiratory epithelium significantly, and increases neutrophils in the nasal surface mucosa in the third month of treatment

Multiple CNS nicotinic receptors mediate L-dopa-induced dyskinesias: studies with parkinsonian nicotinic receptor knockout mice

Accumulating evidence supports the idea that drugs acting at nicotinic acetylcholine receptors (nAChRs) may be beneficial for Parkinson's disease, a neurodegenerative movement disorder characterized by a loss of nigrostriatal dopaminergic neurons. Nicotine administration to parkinsonian animals protects against nigrostriatal damage. In addition, nicotine and nAChR drugs improve L-dopa-induced dyskinesias, a debilitating side effect of L-dopa therapy which remains the gold-standard treatment for Parkinson's disease. Nicotine exerts its antidyskinetic effect by interacting with multiple nAChRs. One approach to identify the subtypes specifically involved in L-dopa-induced dyskinesias is through the use of nAChR subunit null mutant mice. Previous work with β2 and α6 nAChR knockout mice has shown that α6β2* nAChRs were necessary for the development/maintenance of L-dopa-induced abnormal involuntary movements (AIMs). The present results in parkinsonian α4 nAChR knockout mice indicate that α4β2* nAChRs also play an essential role since nicotine did not reduce L-dopa-induced AIMs in such mice. Combined analyses of the data from α4 and α6 knockout mice suggest that the α6α4β2β3 subtype may be critical. In contrast to the studies with α4 and α6 knockout mice, nicotine treatment did reduce L-dopa-induced AIMs in parkinsonian α7 nAChR knockout mice. However, α7 nAChR subunit deletion alone increased baseline AIMs, suggesting that α7 receptors exert an inhibitory influence on L-dopa-induced AIMs. In conclusion, α6β2*, α4β2* and α7 nAChRs all modulate L-dopa-induced AIMs, although their mode of regulation varies. Thus drugs targeting one or multiple nAChRs may be optimal for reducing L-dopa-induced dyskinesias in Parkinson's disease.

Evaluation of nasal mucociliary activity in iatrogenic hypothyroidism

Our aim was to evaluate the effects of iatrogenic, acute and deep hypothyroidism on nasal mucociliary clearance. A total of 46 patients undergoing total or near total thyroidectomy for differentiated thyroid cancer between March and June 2012, and scheduled to undergo radioactive iodine (I-131) ablation therapy followed with an induced hypothyroidism for routine screening were included in the study. Mucociliary clearance test was made during hypothyroid and euthyroid periods in all the patients included in the study. Of the 46 patients included in the study, 37 (%80.4) were females, 9 (%19.6) were males, and the average mucociliary clearance times were 16.78 and 9.58 min during hypothyroid and euthyroid periods, respectively. When the results were compared statistically, mucociliary clearance time measured during hypothyroidism period was found to be significantly longer than the one measured during euthyroid period. Mucociliary clearance time was found to be long during iatrogenic acute and deep hypothyroid periods. During these periods, patients should be followed closely for lower and upper respiratory tract infections.

Stimulation of the dorsal periaqueductal gray enhances spontaneous recovery of a conditioned taste aversion

Due to its relevance to clinical practice, extinction of learned fears has been a major focus of recent research. However, less is known about the means by which conditioned fears re-emerge (i.e., spontaneously recover) as time passes or contexts change following extinction. The periaqueductal gray represents the final common pathway mediating defensive reactions to fear and we have reported previously that the dorsolateral PAG (dlPAG) exhibits a small but reliable increase in neural activity (as measured by c-fos protein immunoreactivity) when spontaneous recovery (SR) of a conditioned taste aversion (CTA) is reduced. Here we extend these correlational studies to determine if inducing dlPAG c-fos expression through electrical brain stimulation could cause a reduction in SR of a CTA. Male Sprague-Dawley rats acquired a strong aversion to saccharin (conditioned stimulus; CS) and then underwent CTA extinction through multiple non-reinforced exposures to the CS. Following a 30-day latency period after asymptotic extinction was achieved; rats either received stimulation of the dorsal PAG (dPAG) or stimulation of closely adjacent structures. Sixty minutes following the stimulation, rats were again presented with the saccharin solution as we tested for SR of the CTA. The brain stimulation evoked c-fos expression around the tip of the electrodes. However, stimulation of the dPAG failed to reduce SR of the previously extinguished CTA. In fact, dPAG stimulation caused rats to significantly suppress their saccharin drinking (relative to controls) - indicating an enhanced SR. These data refute a cause-and-effect relationship between enhanced dPAG c-fos expression and a reduction in SR. However, they highlight a role for the dPAG in modulating SR of extinguished CTAs.

Amygdala-gustatory insular cortex connections and taste neophobia

To examine whether communication between the amygdala and gustatory insular cortex (GC) is required for normal performance of taste neophobia, three experiments were conducted. In Experiment 1, rats with asymmetric unilateral lesions of the basolateral amygdala (BLA) and the GC displayed elevated intake of a novel saccharin solution relative to control subjects. However, an attenuation of neophobia was not found following asymmetric unilateral lesions of the GC and medial amygdala (MeA; Experiment 2) or of the MeA and BLA (Experiment 3). This pattern of results indicates that the BLA and GC functionally interact during expression of taste neophobia and that the MeA functionally interacts with neither the BLA nor the GC. Research is needed to further characterize the nature of the involvement of the MeA in taste neophobia and to determine the function of the BLA-GC interaction during exposure to a new taste.

Effects of chronic nicotine on food intake and anxiety-like behaviour in CB(1) knockout mice

We have evaluated the effects of chronic nicotine administration and withdrawal in food intake and preference, metabolic parameters and anxiety-like behaviour in CB(1) knockout mice and wild-type littermates. Mutant mice showed lower levels of glucose, insulin and cholesterol after two weeks of high fat diet and reduced preference for saccharin solution when compared with wild-type mice. Nicotine reduced body weight and induced anxiogenic-like effects in wild-type, but not in CB(1) knockout mice. Our results suggest a modulatory role of the endocannabinoid system on the effects induced by nicotine on metabolic parameters and anxiety-like responses.

[Saccharin test for the study of mucociliary clearance: reference values for a Spanish population]

OBJECTIVE

Mucociliary transport is an important defense mechanism for the airways. The aim of this study was to establish reference values for nasal mucociliary clearance time (MCT) by means of the saccharin test.

SUBJECTS AND METHODS

A cross-sectional, descriptive, observational study was performed. The variables studied were nasal MCT, age, and sex. We included 249 healthy nonsmokers (134 male and 115 female subjects) aged over 10 years and stratified the sample by age. To establish reference values, percentiles were calculated and lower and upper limits of normal were established at percentiles 2.5 and 97.5, respectively. The association between nasal MCT and the main study variables was then investigated along with the reproducibility of the test.

RESULTS

The following values for nasal MCT were obtained for the sample as a whole: mean (SD), 17.17 (8.43) minutes; median (interquartile range), 16 minutes (12-20 minutes), indicating that the central 50% of the sample fell within this 8-minute range; and maximum and minimum values of 4 to 54 minutes (range, 50 minutes). The upper and lower limits of normal were 6 and 36 minutes, respectively. In addition, it is noteworthy that only 6 subjects had a nasal MCT longer than 36 minutes. No significant differences between male and female subjects were found. Nasal MCT showed a positive correlation with age (rho=0.324; P=.0001). No significant differences were observed in the reproducibility test (P=.208).

CONCLUSIONS

In addition to facilitating reliable data on mucociliary function, the saccharin test is easy to do, inexpensive, and reproducible. The data obtained from this study should allow the results of this test to be correctly interpreted for a given subject's age and so facilitate its use in clinical practice.