The Effects of Adding a Gel-Alike Curcuma longa L. Suspension as Color Agent on Some Quality and Sensory Properties of Yogurt.

Color is an important characteristic of food products. This characteristic is related to consumer acceptability. To use the entire rhizome of Curcuma longa (CL) as a food colorant, a novel gel alike stable suspension (CLS) was previously developed using cellulose nanofibers (CNFs). Therefore, the present study was conducted to evaluate the CLS as a color additive on a stirred yogurt. Three concentrations of CLS were studied (0.1, 0.125, and 0.15 wt. %) and compared to yogurt without CLS. The obtained yogurts were characterized through the determination of pH, titratable acidity, syneresis, color and curcumin content after 1, 7, 14, and 21 days of storage. Additionally, rheological and sensory measurements were performed on the samples after one day of storage. Results show that the addition of CLS does not affect the pH and titratable acidity of the samples, but all the yogurts showed an increase in their syneresis during the storage time, showing a breakdown of the gel structure. Furthermore, the CLS suspension has the ability to impart a yellow color to yogurts, a characteristic that was stable during storage. Finally, the addition of 1 wt. % or 1.25 wt. % of CLS allows the development of a yogurt with adequate sensory perception.

Acquisition and expression of fat conditioned flavor preferences following dopamine D1, opioid and NMDA receptor antagonism in C57BL/6 mice.

Objectives: Inbred mouse strains differ in the pharmacology mediating sugar and fat intake and conditioned flavor preferences (CFP). C57BL/6, BALB/c and SWR inbred mice are differentially sensitive to dopamine (DA) D1, opioid and muscarinic receptor antagonism of sucrose, saccharin or fat intake, and to DA, opioid, muscarinic and N-methyl-D-aspartate (NMDA) receptor antagonism of acquisition of sucrose-CFP. DA D1, opioid and NMDA receptor antagonists differentially alter fat (Intralipid)-CFP in BALB/c and SWR mice. The present study examined whether naltrexone, SCH23390 or MK-801 altered acquisition and expression of Intralipid-CFP in C57BL/6 mice.Methods: In acquisition, groups of male food-restricted C57BL/6 mice received vehicle, naltrexone (1, 5 mg/kg), SCH23390 (50, 200 nmol/kg) or MK-801 (100, 200 µg/kg) before 10 training sessions in which mice alternately consumed two novel-flavored 5% (CS+) and 0.5% (CS-) Intralipid solutions. Six two-bottle CS choice tests followed with both flavors mixed in 0.5% Intralipid without injections. In expression, C57BL/6 mice underwent the 10 training sessions without injections followed by two-bottle CS choice tests 30 min following vehicle, naltrexone (1, 5 mg/kg), SCH23390 (200, 800 nmol/kg) or MK-801 (100, 200 µg/kg).Results: Fat-CFP acquisition in C57BL/6 mice was significantly though marginally reduced following naltrexone, SCH23390 and MK-801. Fat-CFP expression was similarly reduced by naltrexone, SCH23390 and MK-801 in C57BL/6 mice. Discussion: C57BL/6 mice were more sensitive to DA D1, opioid and NMDA antagonists in the expression of fat-CFP relative to sugar-CFP, but were less sensitive to DA D1 and NMDA antagonists in the acquisition of fat-CFP relative to sugar-CFP.

Vacuum impregnation of chitosan coating combined with water-soluble polyphenol extracts on sensory, physical state, microbiota composition and quality of refrigerated grass carp slices.

Herein, the effects of chitosan (CH) coating with different water-soluble polyphenol extracts (pomegranate peel (PPE), grape seed (GSE) and green tea (GTE)) through vacuum impregnation on the quality retention and microflora of refrigerated grass carp fillets were studied. Generally, the quality degradation of carp fillets was remarkably alleviated using coatings when compared to the control. As suggested by microbial enumeration and high-throughput sequencing, protective coatings were conductive to inhibit bacteria growth, especially spoilage bacteria of Pseudomonas. As a result, the indicator related to bacteria such as total volatile basic nitrogen (TVB-N) and K value had lower levels in coating groups than that in control. In addition, coating also slowed down the deterioration of physical properties of color, texture and water holding capacity in fillets, giving fillets a better edible quality. By contrast, the fillets treated by composite coatings had better quality during storage when compared to chitosan coating alone, and a relatively good synergistic antibacterial effect between chitosan and extracts was also observed, especially for CH-GTE. Overall, the best performance to inhibit quality deterioration was recorded in CH-GTE, with the lowest values of TVB-N, TBARS, K-value and water loss, and highest values of shear force and sensory preference among groups.

Dietary Supplementation with Monosodium Glutamate Suppresses Chemotherapy-Induced Downregulation of the T1R3 Taste Receptor Subunit in Head and Neck Cancer Patients.

(Background) We investigated the effect of dietary supplementation with monosodium glutamate (MSG) on chemotherapy-induced downregulation of the T1R3 taste receptor subunit expression in the tongue of patients with advanced head and neck cancer. (Methods) Patients undergoing two rounds of chemoradiotherapy were randomly allocated to a control or intervention group (dietary supplementation with MSG at 2.7 g/day during the second round of chemotherapy). The relative expression of T1R3, a subunit of both umami and sweet taste receptors, in the tongue was assessed by quantitative polymerase chain reaction analysis. Dysgeusia was assessed with a visual analog scale and daily energy intake was evaluated. (Results) T1R3 expression levels in the tongue, taste sensitivity, and daily energy intake were significantly reduced after the first round of chemotherapy compared with before treatment. Furthermore, these parameters significantly decreased after the second round of chemotherapy, but the extent of decrease was significantly attenuated in the MSG group compared with the control group. (Conclusions) MSG supplementation suppresses chemotherapy-induced dysgeusia, possibly due to the inhibition of the T1R3-containing taste receptor downregulation in the tongue, thereby increasing energy intake in patients with advanced head and neck cancer.

Amoxicillin chewable tablets intended for pediatric use: formulation development, stability evaluation and taste assessment.

To cover the unpleasant taste of amoxicillin (250 mg), maize starch (baby food) and milk chocolate were co-formulated. The raw materials and the final formulations were characterized by means of Dynamic Light Scattering (DLS), Differential Scanning Calorimetry (DSC) and Fourier-Transform Infrared (FT-IR) spectroscopy. To evaluate the taste masking two different groups of volunteers were used, according to the Ethical Research Committee of the Aristotle University of Thessaloniki. The optimization of excipients' content in the tablet was determined by experimental design methodology (crossed D-optimal). Due to the matrix complexity, amoxicillin was extracted using liquid extraction and analyzed isocratically by HPLC. The developed chromatographic method was validated (%Recovery 98.7-101.3, %RSD = 1.3, LOD and LOQ 0.15 and 0.45 µg mL-1 respectively) according to the International Conference on Harmonization (ICH) guidelines. The physicochemical properties of the tablets were also examined demonstrating satisfactory quality characteristics (diameter: 15 mm, thickness: 6 mm, hardness <98 Newton, loss of mass <1.0%, disintegration time ∼25min). Additionally, dissolution (%Recovery >90) and in vitro digestion tests (%Recovery >95) were carried out. Stability experiments indicated that amoxicillin is stable in the prepared formulations for at least one year (%Recovery <91).

Assessment of Concentrated Liquid Coffee Acceptance during Storage: Sensory and Physicochemical Perspective.

Concentrated liquid coffees (CLCs) refer to stored extracts stable at environmental temperature, used as ingredients in the retail market. Their low chemical stability affects the sensory profile. This study was performed in two CLCs, one without additives (BIB) and another with a mix of sodium benzoate and potassium sorbate additives (SD), stored at 25 °C for one year. Quantitative-Descriptive (QDA) and discriminant analyses permitted identifying the critical sensory attributes and their evolution over time. The concentrate without additives presented an acceptance limit of 196 days (evaluated at a 50% acceptance ratio), while the additives increased the shelf life up to 226 days (38.9% improvement). The rejection was related to a decreased aroma, increased acidity, and reduced bitterness. A bootstrapped feature selection version of Partial Least Square analysis further demonstrated that reactions of 5-caffeoylquinic acid (5CQA) and 3,5-dicaffeoylquinic acid (3,5diCQA) could cause changes in the aroma at the first degradation stage. In the following stages, changes in fructose and stearic acid contents, a key indicator of acceptance for both extracts possibly related to non-enzymatic reactions involving fructose and other compounds, might affect the bitterness and acidity. These results provided valuable information to understand flavor degradation in CLCs.

Fatty acid composition, oxidative stability, and sensory evaluation of the sausages produced from the meat of pigs fed a diet enriched with 8% of fish oil.

The objective of the present study was to increase by dietary means the long-chain polyunsaturated fatty acid (LC-PUFA) n-3 content in selected meat products. Fatty acid (FA) composition, texture, sensory characteristics, and oxidative stability were determined in the Vienna sausages (V-sausages) and Bologna-type salami (B-salami) produced from the meat of six pigs fed a standard feed (control, C) and six pigs fed a standard feed enriched with 8% of fish oil (F), respectively. The saturated FA content in the unheated FV and FB products was decreased (p < 0.05) by 24% and 39%, PUFA n-6/n-3 ratio improved (p < 0.001) from 13.9 to 2.8 and from 13.5 to 2.6, respectively. LC-PUFA n-3 content in the VF and BF products was 360 and 214 mg/100 g, which corresponds to 80% and 48% of the recommended daily intake. Interestingly, dietary fish oil decreased (p < 0.01) instrumentally the measured core hardness of the V-sausages, but increased (p < 0.001) this texture characteristic in the B-salami. Malondialdehyde content in the VF and BF products increased (p < 0.05) on average by 23% and the flavor of the heated FV sausages scored lower (p < 0.05) in comparison with the C-counterparts.

Effect of the food matrix on the capacity of flavor enhancers in intensifying salty taste.

The effect of the flavor enhancers monoammonium glutamate (MAG), monosodium glutamate (MSG), disodium guanylate (GMP), and disodium inosinate (IMP) on intensifying salty taste in food matrices (shoestring potatoes, requeijão cheese, and beef burgers) with a reduction in the amount of sodium chloride (NaCl) present was evaluated. Experiments were conducted using a central composite rotational design with two variables: the concentrations of flavor enhancer and NaCl added in the food matrix. The effect of IMP was not significant (P > 0.05) on the intensity of salty taste in any of the matrices analyzed. GMP presented lower performance compared to MAG and MSG in intensifying the salty taste of the treatments, regardless of the reduction of NaCl. Compared to MSG and GMP, MAG showed greater efficiency in intensifying the salty taste in requeijão cheese and beef burger with a reduction of 25%, 50%, 75%, and 100% of NaCl. MSG presented higher efficiency compared to MAG and GMP when applied in shoestring potatoes for all reductions of NaCl tested (25%, 50%, and 75%). The ability of flavor enhancers to improve the salty taste depends on the effect of the flavor enhancer, the complexity of the food matrix, and the reduction of NaCl in foods. PRACTICAL APPLICATIONS: The complexity of the food matrix plays a significant role in the perception of salty taste in sodium-reduced products. In these products, sodium reduction may affect the taste enhancer's effect of enhancing salty taste. Therefore, this study broadens the knowledge of the effects of flavor enhancers on different foods, as well as the ability to enhance salty taste in food matrices with NaCl reduction. Moreover, it provides information on how to reduce the sodium content in these matrices while maintaining the same perception of salty taste as a conventional matrix.

Taste Function in Adults Undergoing Cancer Radiotherapy or Chemotherapy, and Implications for Nutrition Management: A Systematic Review.

BACKGROUND: Taste changes are commonly reported by people with cancer undergoing radio- or chemotherapy. Taste changes may compromise dietary intake and nutritional status. OBJECTIVE: To understand whether or not taste change is associated with cancer diagnosis or treatment modality in adults. METHODS: A systematic literature search up to December 31, 2019, was conducted using PubMed, Embase, and PsycInfo (International Prospective Register of Systematic Reviews protocol no. CRD42019134005). Studies in adults with cancer objectively assessing the effect of a cancer diagnosis or chemotherapy and/or radiotherapy treatment on taste function compared with healthy controls or within participant changes were included. Additional outcomes were food liking, appetite, dietary intake, nutritional status, and body composition. Reference lists of relevant articles were searched to identify additional articles. Quality was assessed using the Academy of Nutrition and Dietetics quality criteria checklist. RESULTS: A total of 24 articles were included, one of which consisted of two studies that reported the effects of radiotherapy and chemotherapy separately. From the total 25 studies reported in 24 published articles, 14 studies examined effects of radiotherapy, and remaining 11 studies examined chemotherapy. There is limited evidence of a cancer diagnosis per se contributing to taste dysfunction. Impaired taste function was reported in almost all radiotherapy studies, occurring as early as Week 3 of treatment and lasting for 3 to 24 months posttreatment. During chemotherapy, impairment of taste function was less consistently reported, occurring as early as the first few days of chemotherapy, and persisting up to 6 months posttreatment. Taxane-based chemotherapy was reported to affect taste function more than other treatments. Several studies reported reduced liking for food, appetite, and dietary intake. Only one study reported nutritional status of participants, finding no association between taste function and nutritional status. No studies examined associations between taste changes and body composition. CONCLUSIONS: This review highlights the importance of considering treatment modality in practice. Research is required to identify factors contributing to taste alteration and to inform evidence-based interventions.

Identification of two bitter components in Zanthoxylum bungeanum Maxim. and exploration of their bitter taste mechanism through receptor hTAS2R14.

Bitterness is an inherent organoleptic characteristic affecting the flavor of Zanthoxylum bungeanum Maxim. In this study, the vital bitter components of Z. bungeanum were concentrated through solvent extraction, sensory analysis, silica gel chromatography, and thin-layer chromatographic techniques and subsequently identified by UPLC-Q-TOF-MS. Two components with the highest bitterness intensities (BIs), such as 7-methoxycoumarin and 8-prenylkaempferol were selected. The bitter taste perceived thresholds of 7-methoxycoumarin and 8-prenylkaempferol were 0.062 mmol/L and 0.022 mmol/L, respectively. Moreover, the correlation between the contents of the two bitter components and the BIs of Z. bungeanum were proved. The results of siRNA and flow cytometry showed that 7-methoxycoumarin and 8-prenylkaempferol could activate the bitter receptor hTAS2R14. The results concluded that 7-methoxycoumarin and 8-prenylkaempferol contribute to the bitter taste of Z. bungeanum.

Identification and Comparison of Peptides from Chickpea Protein Hydrolysates Using Either Bromelain or Gastrointestinal Enzymes and Their Relationship with Markers of Type 2 Diabetes and Bitterness.

The chickpea (Cicer arietinum L.) is one of the most important pulses worldwide. The objective was to identify, compare and evaluate peptides from chickpea hydrolysates produced by two enzymatic treatments. The antidiabetic potential and bitterness of the peptides and induction of bitter receptors were identified in silico. Proteins were isolated from the Kabuli variety. Peptides were produced from the proteins using a simulated digestive system (pepsin/pancreatin, 1:50 Enzyme/Protein, E/P), and these peptides were compared with those produced via bromelain hydrolysis (1:50 E/P). The protein profiles, sequences and characteristics of the peptides were evaluated. The biochemical inhibition and molecular docking of dipeptidyl peptidase-IV (DPP-IV), α-amylase and α-glucosidase were also studied. The molecular docking identified peptides from enzymatic hydrolysis as inhibitors of DPP-IV. The high hydrophobicity of the peptides indicated the potential for bitterness. There was no correlation between peptide length and DPP-IV binding. Peptides sequenced from the pepsin/pancreatin hydrolysates, PHPATSGGGL and YVDGSGTPLT, had greater affinity for the DPP-IV catalytic site than the peptides from the bromelain hydrolysates. These results are in agreement with their biochemical inhibition, when considering the inhibition of sitagliptin (54.3 µg/mL) as a standard. The bitter receptors hTAS2R38, hTAS2R5, hTAS2R7 and hTAS2R14 were stimulated by most sequences, which could be beneficial in the treatment of type 2 diabetes. Chickpea hydrolysates could be utilized as functional ingredients to be included in the diet for the prevention of diabetes.

Suppression of Oral Sweet Sensations during Consumption of Sweet Food in Humans: Effects on Gastric Emptying Rate, Glycemic Response, Appetite, Food Satisfaction and Desire for Basic Tastes.

Suppression of oral sweet sensation (OSS) acutely reduces intake of sweet-tasting food due to lower liking. However, little is known about other physiological responses during both the prandial and postprandial phase. Here, we explored the effects of Gymnema sylvestre (GS)-based suppression of OSS of several types of sweet-tasting food (muffin, sweet yogurt, banana) on gastric emptying, blood glucose (BG), plasma insulin (PI), appetite indices (hunger, fullness and prospective consumption), satisfaction and desire for tastes. Fifteen healthy subjects (22 ± 3 years, 9 women) took part in the study. Subjects rinsed their mouth with either GS solution or distilled water before eating the sweet-tasting food. Subjects felt decreased sweet taste intensity and reduced taste liking associated with GS rinsing after consuming each food, compared with rinsing with distilled water (p < 0.05). Gastric emptying, BG, PI and appetite indices during and after the prandial phase did not significantly change with GS rinsing compared to rinsing with distilled water (p > 0.05). Higher desire for sweet taste as well as lower satisfaction (p < 0.05) in the postprandial phase were observed with GS rinsing. These results suggest that the suppression of OSS does not affect gastric emptying, glycemic response and appetite during and after consumption of sweet-tasting food.

Discovery and Development of S6821 and S7958 as Potent TAS2R8 Antagonists.

In humans, bitter taste is mediated by 25 TAS2Rs. Many compounds, including certain active pharmaceutical ingredients, excipients, and nutraceuticals, impart their bitter taste (or in part) through TAS2R8 activation. However, effective TAS2R8 blockers that can either suppress or reduce the bitterness of these compounds have not been described. We are hereby reporting a series of novel 3-(pyrazol-4-yl) imidazolidine-2,4-diones as potent and selective TAS2R8 antagonists. In human sensory tests, S6821 and S7958, two of the most potent analogues from the series, demonstrated efficacy in blocking TAS2R8-mediated bitterness and were selected for development. Following data evaluation by expert panels of a number of national and multinational regulatory bodies, including the US, the EU, and Japan, S6821 and S7958 were approved as safe under conditions of intended use as bitter taste blockers.

Taste masking of water-soluble drug by solid lipid microspheres: a child-friendly system established by reversed lipid-based nanoparticle technique.

OBJECTIVES: A child-friendly taste-masking strategy using solid lipid microsphere (SLM) has been proposed to obscure the undesirable taste of some water-soluble drugs. In this study, the reversed lipid-based nanoparticle (RLBN) technique was used to encapsulate a water-soluble drug to facilitate the preparation of SLM. METHODS: The model drug used was atomoxetine hydrochloride (ATX), and a three-step method was used to prepare ATX-RLBN. Taste-masking microsphere (ATX-RLBN-SLM) was prepared by the spray chilling method. The drug release mechanism was studied by high-performance liquid chromatography and scanning electron microscopy. Moreover, in vitro taste evaluation method was established and ATX bioavailability was investigated employing pharmacokinetic studies. KEY FINDINGS: The obtained ATX-RLBN-SLM had smooth spherical particles with a size of about 80 µm. The drug encapsulation and loading efficiencies were 98.28% ± 0.59% and 0.89% ± 0.04%, respectively. In vitro drug release studies showed that nearly 96% drug was retained in the microspheres within 10 min at pH 6.8 and a complete release was triggered by lipase, accompanied by variation in the morphology. Taste assessment revealed that ATX-RLBN-SLM could efficiently mask the bitter taste and improved the bioavailability of ATX. CONCLUSIONS: Atomoxetine hydrochloride-reversed lipid-based nanoparticle-solid lipid microsphere exhibited excellent taste-masking effect with negligible leakage in the oral cavity environment and thorough collapse upon lipase stimulation, simultaneously enhancing the bioavailability of ATX. The study paves a new way to efficiently mask the undesirable taste of some water-soluble drugs.

Efficacy of Long-Term Feeding of α-Glycerophosphocholine for Aging-Related Phenomena in Old Mice.

α-Glycerophosphocholine (GPC) is a natural source of choline. It reportedly prevents aging-related decline in cognitive function, but the underlying mechanism remains unclear. Although it is understood that aging influences taste sensitivity and energy regulation, whether GPC exerts antiaging effects on such phenomena requires further elucidation. Here, we used old C57BL/6J mice that were fed a GPC-containing diet, to investigate the molecular mechanisms underlying the prevention of a decline in cognitive function associated with aging and examine the beneficial effects of GPC intake on aging-related phenomena, such as taste sensitivity and energy regulation. We confirmed that GPC intake reduces the aging-related decline in the expression levels of genes related to long-term potentiation. Although we did not observe an improvement in aging-related decline in taste sensitivity, there was a notable improvement in the expression levels of ß-oxidation-associated genes in old mice. Our results suggest that the prevention of aging-related decline in cognitive function by GPC intake may be associated with the improvement of gene expression levels of long-term potentiation. Furthermore, GPC intake may positively influence lipid metabolism.

Is rat a good model for assessment of particulate-based taste-masked formulations?

Recently there has been an increased interest to develop specialised dosage forms that are better suited to specific patient populations, such as paediatrics and geriatrics. In these patient populations the acceptability of the oral dosage form can be paramount to the products success. However, many Active Pharmaceutical Ingredients (APIs) are known to cause an aversive taste response. One way to increase the acceptability and to enhance the palatability of the formulation is to design coated taste-masked particulate-based dosage forms. The masking of poorly tasting drugs with physical barriers such as polymer coatings can be utilised to prevent the release of drug within the oral cavity, thus preventing a taste response. However, currently, there are few assessment tools and models available to test the efficiency of these particulate-based taste-masked formulations. The rat brief access taste aversion model has been shown to be useful in assessment of taste for liquid dosage forms. However, the applicability of the rat model for particulate-based taste masked formulations is yet to be assessed. It is not understood whether dissolution, solubility and thus exposure of the drug to taste receptors would be the same in rat and human. Therefore, rat saliva must be compared to human saliva to determine the likelihood that drug release would be similar within the oral cavity for both species. In this study rat saliva was characterised for parameters known to be important for drug dissolution, such as pH, buffer capacity, surface tension, and viscosity. Subsequently dissolution of model bitter tasting compounds, sildenafil citrate and efavirenz, in rat saliva was compared to dissolution in human saliva. For all parameters characterised and for the dissolution of both drugs in rat saliva, a substantial difference was observed when compared to human saliva. This discrepancy in saliva parameters and dissolution of model drugs suggests that preclinical taste evaluation of particulate-based taste-masked formulations suggests rat is not a good model for predicting taste of solid dosage forms or undissolved drug where dissolution is required. Alternative preclinical in vivo models in other species, or improved biorelevant in vitro models should be considered instead.

[Influence of diagnostic pathway on clinical and non-conventional therapies use in women with breast cancer of the cohort DAMA]. / Influencia de la vía diagnóstica en la clínica y el uso de terapias no convencionales en mujeres con cáncer de mama de la cohorte DAMA.

OBJECTIVE: To describe and analyze the characteristics of breast cancer tumours according to the diagnostic pathway. We analyse the adverse effects of the treatments and the use of unconventional therapies in order to alleviate them. METHOD: Descriptive design nested in a mixed cohort (Cohort DAMA). The dependent variable was the route to diagnosis of breast cancer. The independent variables were age, body mass index, social class, disposable family income, type of tumour, histological degree, tumour stage, recurrences, treatment, adverse effects derived from treatments and unconventional therapies. Bivariate descriptive analyses were performed and univariate and multivariate regression models were adjusted; and graphic representations of the unconventional therapies. RESULTS: There are differences in the characteristics of the tumours, and the impact of the adverse effects derived from the treatments. The patients diagnosed by screening were older, from a high social class, had a higher percentage of tumours of grade I differentiation, initial stages, fewer recurrences and fewer adverse effects due to treatment, although this was not different in the screening group compared to the rest. There was also less use of unconventional therapies. CONCLUSIONS: The results indicate that the implementation of screening programmes increases the possibility of detecting tumours in initial stages and with therapies with fewer adverse effects. As a result, there is less need to resort to unconventional therapies.

Microinjection of urotensin II into the pedunculopontine tegmentum leads to an increase in the consumption of sweet tastants.

The pedunculopontine tegmentum (PPTg) plays a role in processing multiple sensory inputs and innervates brain regions associated with reward-related behaviors. The urotensin II receptor, activated by the urotensin II peptide (UII), is selectively expressed by the cholinergic neurons of the PPTg. Although the exact function of cholinergic neurons of the PPTg is unknown, they are thought to contribute to the perception of reward magnitude or salience detection. We hypothesized that the activation of PPTg cholinergic neurons would alter sensory processing across multiple modalities (ex. taste and hearing). Here we had three aims: first, determine if cholinergic activation is involved in consumption behavior of palatable solutions (sucrose). Second, if so, distinguish the impact of the caloric value by using saccharin, a zero calorie sweetener. Lastly, we tested the UII-mediated effects on perception of acoustic stimuli by measuring acoustic startle reflex (ASR). Male Sprague-Dawley rats were bilaterally cannulated into the PPTg, then placed under food restriction lasting the entire consumption experiment (water ad lib.). Treatment consisted of a microinjection of either 1 µL of aCSF or 1 µL of 10 µM UII into the PPTg, and the rats were immediately given access to either sucrose or saccharin. For the remaining five days, rats were allowed one hour access per day to the same sweet solution without any further treatments. During the saccharin experiment rats were tested in a contact lickometer which recorded each individual lick to give insight into the microstructure of the consumption behavior. ASR testing consisted of a baseline (no treatment), treatment day, and two additional days (no treatment). Immediately following the microinjection of UII, consumption of both saccharin and sucrose increased compared to controls. This significant increase persisted for days after the single administration of UII, but there was no generalized arousal or increase in water consumption between testing sessions. The effects on ASR were not significant. Activating cholinergic PPTg neurons may lead to a miscalculation of the salience of external stimuli, implicating the importance of cholinergic input in modulating a variety of behaviors. The long-lasting effects seen after UII treatment support further research into the role of sensory processing on reward related-behaviors at the level of the PPTg cholinergic neurons.

Conditioned taste avoidance induced by the combination of heroin and cocaine: Implications for the use of speedball.

Speedball (heroin + cocaine) is a prevalent drug combination among intravenous drug users. Although its use is generally discussed to be a function of changes in the rewarding effects of either or both drugs, changes in the aversive effects of either drug may also be impacted (weakened) by the combination. To address this latter possibility and its potential role in the use of speedball, the present studies examined the interaction of cocaine and heroin in taste avoidance conditioning. In Experiment 1, male Sprague-Dawley rats were given access to a novel saccharin solution and then injected with either vehicle or heroin (3.2 mg/kg, IP) followed immediately by various doses of cocaine (10, 18 or 32 mg/kg, SC). At the two lowest doses of cocaine, only animals injected with the drug combination (H + C) displayed a taste avoidance relative to control subjects (taste avoidance was induced with both the combination and the high dose of cocaine). At no dose did animals injected with the combination of heroin and cocaine drink more than animals injected with cocaine alone. In Experiment 2, male Sprague-Dawley rats were similarly treated but injected with vehicle or cocaine (10 mg/kg) followed by injections of various doses of heroin (1.8, 3.2, 5.6 or 10 mg/kg). At the three highest doses of heroin, only animals injected with the drug combination (C + H) displayed significant avoidance relative to control subjects (no avoidance was evident with the combination of cocaine and the low dose of heroin). At no dose did animals injected with the combination of cocaine and heroin drink more than animals injected with heroin alone. Together, these results suggest that the aversive effects of heroin and cocaine are not attenuated by co-administration by cocaine and heroin, respectively. The importance of this for the use of speedball was discussed.

Strain differences in muscarinic cholinergic receptor antagonism of fat intake and acquisition and expression of fat-conditioned flavor preferences in male BALB/c, C57BL/6 and SWR mice.

Murine strain differences occur for both intakes of and preferences for sugars and fats. Previous studies demonstrated that the muscarinic cholinergic receptor antagonist, scopolamine (SCOP) more potently reduced sucrose and saccharin intakes in inbred C57BL/6 and BALB/c than SWR mice, sucrose-conditioned flavor preferences (CFP) expression in BALB/c, but not C57BL/6 or SWR mice, and sucrose-CFP acquisition in BALB/c relative to SWR and C57BL/6 mice. Although fat intake and fat-CFP are observed in all three strains, strain-specific effects were previously observed following dopamine D1, opiate and NMDA receptor antagonism of sweet and fat intake and CFP. The present study investigated whether muscarinic receptor antagonism differentially affected fat (Intralipid) intake and preferences in these strains by examining whether SCOP altered fat (Intralipid) intake and fat-CFP expression and acquisition in BALB/c, C57BL/6 and SWR mice. SCOP (0.1-10 mg/kg) significantly reduced Intralipid (5%) intake in all three strains across 2 h. In fat-CFP expression experiments, food-restricted mice consumed one flavored (conditioned stimulus (CS)+, 5 sessions) Intralipid (5%) solution and a differently-flavored (CS-, 5 sessions) Intralipid (0.5%) solution. Two-bottle CS choice tests with the two flavors mixed in 0.5% Intralipid occurred following vehicle and two SCOP doses (1, 5 mg/kg). SCOP elicited small, but significant reductions in fat-CFP expression in BALB/c and C57BL/6, but not SWR mice. In fat-CFP acquisition experiments, separate groups of BALB/c, C57BL/6 and SWR mice were treated prior to the ten acquisition training sessions with vehicle or two SCOP (2.5, 5 mg/kg) doses followed by six two-bottle choice tests without injections. SCOP eliminated fat-CFP acquisition in all three strains. Thus, muscarinic receptor signaling mediates learning, and to a lesser degree maintenance of fat-CFP while maximally inhibiting fat intake in the three strains.