Dimenhydrinate effect on cerebral oxygen status and salivary chromogranin-A during cognitive tasks

Erken dönem civciv embriyo modelinde dimenhidrinatın nöral tüp gelişimi üzerine etkisi

Amaç: Bu çalışmada dimenhidrinat’ın erken dönem civciv embriyo modelinde nöral tüp gelişimi üzerindeki etkilerinin araştırılması amaçlanmıştır. Gereç ve Yöntem: Çalışmada 32 fertil, spesifik patojen olmayan yumurta kullanıldı. Tüm yumurtalar her bir grupta 8 adet olacak şekilde dört gruba ayrıldı. İnkübasyonun 28. saatinde deney gruplarına üç farklı dozda (0,7, 1,4, 2,1 mg/kg) dimenhidrinat ve kontrol grubuna serum fizyolojik enjekte edildi. İnkübasyonun 48. saatinde tüm embriyolar diseke edildi ve ışık mikroskobu altında histolojik olarak değerlendirildi. Bulgular: Kontrol, düşük, orta ve yüksek doz grubu embriyoları morfolojik olarak değerlendirildiğinde, kraniokaudal uzunluk ortalamaları sırasıyla; 8493,73±1342,90 µm, 5743,61±770,3 µm, 5572,62±315,32 µm, 5306,55±1135,99 µm, somit sayıları ortalamaları sırasıyla; 15,91±1,62, 15,38±1,19, 15,13±0,83, 10,63±5,15‘dir. Dimenhidrinat dozundaki artışa bağlı olarak kraniokaudal uzunluklarının ve somit sayılarının azaldığı tespit edildi. Dimenhidrinat doz artışına bağlı olarak nöral tüp açıklığının arttığı belirlendi . Sonuç: Bu çalışmada, erken dönem civciv embriyo modelinde dimenhidrinat uygulanan gruplarda doz artışına bağlı olarak nörogenezisin ve morfolojik gelişimin olumsuz etkilendiği görüldü.

Misuse and dependence of dimenhydrinate: A mixed studies systematic review

BACKGROUND

Dimenhydrinate (DMH) is an antihistamine used to treat nausea and vomiting. Although widely available in pharmacies as an over the counter medication, there have been reports of potential DMH tolerance and dependence and a possible euphoric potential accompanying heavy use (>100 mg/day). Despite the potential for misuse, there is a gap in the literature concerning patterns, characteristics, and potential mechanisms of DMH misuse.

AIMS

This review aimed to synthesize evidence on the pharmacology, clinical effects, and management of DMH misuse and dependence to inform clinical decision making and relevant drug policy.

METHODS

We conducted a systematic review in accordance with the PRISMA guidelines and using Cochrane collaboration methods. We searched seven databases from their inception through July 2019. To be included in the review, studies needed to measure or focus on one or more dimensions of morbidity or mortality related to the misuse of DMH. Quantitative, qualitative and mixed-method studies were included in order to capture the breadth of possible studies. Studies were excluded if they did not fit into the conceptual framework of the study of if they focused primarily on the misuse of other substances. A narrative synthesis of study findings was pursued given the limited capacity for a quantitative meta-analysis.

FINDINGS

We identified 24 studies, which described a range of neuropsychiatric sequelae related to DMH consumption, including seizures, psychosis, depression, intoxication (resembling anticholinergic syndrome) and withdrawal. The sedative and euphoric properties, readily available nature, and low cost of DMH appear to facilitate DMH dependence, which were more commonly reported among individuals who had concurrent psychiatric disorders, displaying symptoms such as low motivation, poor concentration, and delirium. The overall quality of studies identified by this review was low-largely because the majority of studies were case reports or review articles, with few intervention or cohort studies.

CONCLUSIONS

There is some evidence to suggest the existence of DMH-related syndromes involving intoxication, withdrawal, and dependence, more commonly among long-term, heavy DMH consumers. However, higher quality studies are needed to confirm preliminary findings that there may be a biological basis for such syndromes.

Acute ingestion of rosemary water: Evidence of cognitive and cerebrovascular effects in healthy adults

BACKGROUND

The use of herbal extracts and supplements to enhance health and wellbeing is increasing in western society.

AIMS

This study investigated the impact of the acute ingestion of a commercially available water containing an extract and hydrolat of rosemary ( Rosmarinus officinalis L. syn. Salvia rosmarinus Schleid.). Aspects of cognitive functioning, mood and cerebrovascular response measured by near-infrared spectroscopy provided the dependent variables.

METHODS

Eighty healthy adults were randomly allocated to consume either 250 mL of rosemary water or plain mineral water. They then completed a series of computerised cognitive tasks, followed by subjective measures of alertness and fatigue. Near-infrared spectroscopy monitored levels of total, oxygenated and deoxygenated haemoglobin at baseline and throughout the cognitive testing procedure.

RESULTS

Analysis of the data revealed a number of statistically significant, small, beneficial effects of rosemary water on cognition, consistent with those found previously for the inhalation of the aroma of rosemary essential oil. Of particular interest here are the cerebrovascular effects noted for deoxygenated haemoglobin levels during cognitive task performance that were significantly higher in the rosemary water condition. This represents a novel finding in this area, and may indicate a facilitation of oxygen extraction at times of cognitive demand.

CONCLUSION

Taken together the data suggest potential beneficial properties of acute consumption of rosemary water. The findings are discussed in terms of putative metabolic and cholinergic mechanisms.

Dietary nitrate modulates cerebral blood flow parameters and cognitive performance in humans: A double-blind, placebo-controlled, crossover investigation

Nitrate derived from vegetables is consumed as part of a normal diet and is reduced endogenously via nitrite to nitric oxide. It has been shown to improve endothelial function, reduce blood pressure and the oxygen cost of sub-maximal exercise, and increase regional perfusion in the brain. The current study assessed the effects of dietary nitrate on cognitive performance and prefrontal cortex cerebral blood-flow (CBF) parameters in healthy adults. In this randomised, double-blind, placebo-controlled, parallel-groups study, 40 healthy adults received either placebo or 450 ml beetroot juice (~5.5 mmol nitrate). Following a 90 minute drink/absorption period, participants performed a selection of cognitive tasks that activate the frontal cortex for 54 min. Near-Infrared Spectroscopy (NIRS) was used to monitor CBF and hemodynamics, as indexed by concentration changes in oxygenated and deoxygenated-haemoglobin, in the frontal cortex throughout. The bioconversion of nitrate to nitrite was confirmed in plasma by ozone-based chemi-luminescence. Dietary nitrate modulated the hemodynamic response to task performance, with an initial increase in CBF at the start of the task period, followed by consistent reductions during the least demanding of the three tasks utilised. Cognitive performance was improved on the serial 3s subtraction task. These results show that single doses of dietary nitrate can modulate the CBF response to task performance and potentially improve cognitive performance, and suggest one possible mechanism by which vegetable consumption may have beneficial effects on brain function.

Latrepirdine for Alzheimer's disease

BACKGROUND

Current treatments for Alzheimer's disease (AD) provide modest symptomatic relief but do not slow the progression of the disease. Latrepirdine may modulate several targets involved in AD pathology, including lipid peroxidation, mitochondrial permeability, voltage-gated calcium ion channels as well as neurotransmitter receptor activity, and thus potentially represents both a symptomatic and disease-modifying intervention. Several randomized, placebo-controlled trials have sought to evaluate the effect of latrepirdine on cognition, function and behaviour in patients with AD.

OBJECTIVES

To evaluate the efficacy and safety of latrepirdine for the treatment of AD.

SEARCH METHODS

We searched the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 4 June 2014 using the terms: latrepirdine OR dimebon OR dimebolin OR 2,3,4,5-tetrahydro-2,8-dimethyl-5- (2-(6-methyl-3-pyridyl)ethyl)-1H-pyrido(4,3-b)indole.

SELECTION CRITERIA

We included all randomized, double-blind, placebo-controlled trials where latrepirdine was administered to patients with mild, moderate or severe AD.

DATA COLLECTION AND ANALYSIS

We assessed the quality of studies and two authors extracted data. We calculated mean difference (MD), risk ratio (RR) and 95% confidence interval (CI) on an intention-to-treat (ITT) basis for all relevant outcome measures.

MAIN RESULTS

Seven trials involving a total of 1697 participants were found and six were included in the quantitative analyses. No data were available from the seventh trial. Three trials involving 1243 patients were included in analyses of efficacy outcomes, and four trials involving 1034 patients were included in analyses of safety and tolerability outcomes. We judged five trials to be at high risk of bias due to selective outcome reporting and three to be at high risk of attrition bias. There was low quality evidence favouring latrepirdine on the Clinician's Interview - Based Impression of Change Plus Caregiver Input after 26 weeks (CIBIC-Plus) (MD -0.60, 95% CI -0.89 to -0.31, 1 study, P < 0.001). Due to imprecision in the results, it was not possible to determine whether latrepirdine had any effect on cognition measured with the Alzheimer's Disease Assessment Scale cognitive subscale (ADAS-Cog) (MD -1.49, 95% CI -3.47 to 0.49, 3 studies, P = 0.14) or the Mini-Mental State Examination (MMSE) (MD 0.59, 95% CI -0.94 to 2.11, 3 studies, P = 0.45), or on function measured with the Alzheimer's Disease Co-operative Study - Activities of Daily Living scale (ADCS-ADL) (MD 1.00, 95% CI -1.15 to 3.15, 3 studies, P = 0.36) at study endpoint (26 or 52 weeks). We considered the evidence provided on these outcomes to be of overall low quality. However, there was some high quality evidence showing a very small benefit of latrepirdine on the Neuropsychiatric Inventory (NPI) (MD -1.77, 95% CI -3.09 to -0.45, 3 studies, P = 0.009) at study endpoint (26 or 52 weeks). Additionally, moderate quality evidence suggested that latrepirdine and placebo were comparable in adverse events (RR 1.03, 95% CI 0.93 to 1.14, P = 0.51), serious adverse events (RR 0.86, 95% CI 0.55 to 1.35, P = 0.52), dropouts (RR 0.91, 95% CI 0.65 to 1.27, P = 0.57) and dropouts due to adverse events (RR 0.98, 95% CI 0.57 to 1.67, P = 0.93).

AUTHORS' CONCLUSIONS

Our meta-analysis is limited by the small number of studies, imprecision, inconsistencies between studies and likelihood of bias. Nevertheless, the evidence to date suggests that while not associated with an increased risk of adverse events compared with placebo, there is no effect of latrepirdine on cognition and function in mild-to-moderate AD patients, though there appears to be a modest benefit for behaviour. Further studies should investigate the potential benefit of latrepirdine on neuropsychiatric symptoms in AD.

Effects of olfactory stimulation from the fragrance of the Japanese citrus fruit yuzu (Citrus junos Sieb. ex Tanaka) on mood states and salivary chromogranin A as an endocrinologic stress marker

OBJECTIVE

This study investigated the soothing effects of fragrance from yuzu, a Japanese citrus fruit (Citrus junos Sieb. ex Tanaka), with salivary chromogranin A (CgA) used as an endocrinologic stress marker reflecting sympathetic nervous system activity.

METHODS

Twenty healthy women (mean age, 20.5 ± 0.1 years) participated in a randomized, controlled, crossover study. Participants were examined on two separate occasions-once using the yuzu scent and once using unscented water as a control-in the follicular phase. This experiment measured salivary CgA and the Profile of Mood States (POMS) as a psychological index before and after the aromatic stimulation.

RESULTS

Ten-minute inhalation of the yuzu scent significantly decreased salivary CgA. At 30 minutes after the inhalation period, the salivary CgA level further decreased. In addition, POMS revealed that inhalation of the aromatic yuzu oil significantly decreased total mood disturbance, a global measure of affective state, as well as four subscores of emotional symptoms (tension-anxiety, depression-dejection, anger-hostility, and confusion), as long as 30 minutes after the olfactory stimulation.

CONCLUSIONS

Yuzu's aromatic effects may alleviate negative emotional stress, which, at least in part, would contribute to the suppression of sympathetic nervous system activity.

Increased salivary chromogranin A in women with severe negative mood states in the premenstrual phase

The present study investigated whether salivary chromogranin A (CgA), a psychological stress marker associated with sympathetic nervous system activity, changes during the menstrual cycle in women with different degrees of premenstrual psychoemotional symptoms. Forty-five women (28.6 ± 1.3 years) with regular menstrual cycles participated in this study. Salivary CgA and cortisol were measured during the follicular and late-luteal phases. The authors used the Profile of Mood State (POMS) to assess current mood states of subjects in each menstrual phase and divided the subjects into three groups depending on increase of total mood disturbance (TMD), a global measure of affective states of POMS from the follicular to the late-luteal phase: Low (4.1 ± 0.7%), Middle (18.7 ± 1.2%) and High (51.7 ± 7.4%). Results showed no intramenstrual cycle differences in salivary CgA in the Low and Middle groups. Women in the High group, in contrast, had a significantly higher level of salivary CgA in the late-luteal phase compared to that of the follicular phase. Additionally, salivary CgA level significantly and positively correlated with TMD and four emotional subscales: tension-anxiety, depression-dejection, anger-hostility and confusion in the late-luteal phase. No intergroup or menstrual-cycle difference occurred in the salivary cortisol. This study indicates a significant late-luteal increase in salivary CgA, reflecting an increase of sympathetic nerve activity in women who experience a substantial increase (>30%) in a cluster of negative psychoemotional symptoms premenstrually. Furthermore, salivary CgA, as opposed to salivary cortisol, could serve as a reliable noninvasive biomarker to more sensitively evaluate neuropsychophysiological fluctuations during the menstrual cycle.

Epigallocatechin gallate, cerebral blood flow parameters, cognitive performance and mood in healthy humans: a double-blind, placebo-controlled, crossover investigation

OBJECTIVE

The aim of the study was to assess the effects of oral ingestion of the 'green tea' polyphenol epigallocatechin gallate (EGCG) on cognitive performance, mood and localised cerebral blood flow (CBF) parameters in healthy human adults.

METHOD

In this double-blind, placebo-controlled, crossover study, 27 healthy adults received placebo and two doses (135 and 270 mg) of EGCG in counterbalanced order on separate days. Following a 45-min resting absorption period, participants performed a selection of computerised cognitive tasks that activate the frontal cortex for a further 42 min. CBF and haemodynamics, as indexed by concentration changes in oxygenated and deoxygenated haemoglobin, were assessed in the frontal cortex throughout the post-treatment period using Near-infrared spectroscopy (NIRS).

RESULTS

During the post-dose task performance period, the administration of 135 mg EGCG resulted in reduced CBF in the frontal cortex, as indexed by significantly lower concentrations of both oxygenated and total haemoglobin, in comparison with placebo. Heart rate was significantly reduced from pre dose to post dose across all treatments. No significant differences were observed for the level of deoxygenated haemoglobin or on any of the cognitive performance/mood measures.

CONCLUSIONS

These results demonstrate that a single dose of orally administered EGCG can modulate CBF parameters in healthy humans but that this is not associated with changes in cognitive performance or mood.

DHA-rich oil modulates the cerebral haemodynamic response to cognitive tasks in healthy young adults: a near IR spectroscopy pilot study

The impact of dietary n-3 PUFA on behavioural outcomes has been widely researched; however, very little attention has been given to their impact on brain functioning in physiological terms. A total of twenty-two healthy adults took part in this double-blind, placebo-controlled study, wherein the cerebral haemodynamic effects of 12 weeks of daily dietary supplementation with either 1 g DHA-rich or 1 g EPA-rich fish oil (FO) or placebo (1 g olive oil) were assessed. Relative changes in the concentration of oxygenated Hb (oxy-Hb) and deoxygenated Hb were assessed in the prefrontal cortex using near IR spectroscopy (NIRS) during the performance of four computerised cognitive tasks. Supplementation with DHA-rich FO, in comparison with placebo, resulted in a significant increase in the concentrations of oxy-Hb and total levels of Hb, indicative of increased cerebral blood flow (CBF), during the cognitive tasks. In comparison, no effect on CBF was observed following supplementation with EPA-rich FO, where concentration changes in the chromophores followed the same pattern as placebo. These encouraging pilot data warrant further application of NIRS in this area.

Cognitive domains affected by histamine H(1)-antagonism in humans: a literature review

The neurotransmitter histamine has been suggested to be involved in cognitive functioning. Generally, studies in animals have shown a decrease in performance after decreasing histamine neurotransmission and improved performance after increasing histamine neurotransmission. It is unclear, however, what role histamine plays in cognition in humans. Up until now, most data are derived from studies and reviews that aimed to assess the sedative potential of H(1)-antagonists and not the effects on cognition in particular. The objective of this paper is specifically to review which cognitive domains are affected by H(1)-antagonists. Taken together, 90 experimental studies on the performance effects of sedative H(1)-antagonists published between 1973 and 2009 were reviewed. Results showed that psychomotor skills and attention are most frequently impaired and memory the least. Tasks assessing memory that were affected usually required rapid responses. It was concluded that both the complexity of the task as well as the demand for information processing speed determines the sensitivity to the effects of central H(1)-antagonism. The importance of the sensitive cognitive domains to histaminergic dysfunction, as well as the relation between histamine related decrease in arousal and task performance deserve further research.

Effects of resveratrol on cerebral blood flow variables and cognitive performance in humans: a double-blind, placebo-controlled, crossover investigation

BACKGROUND

The many putative beneficial effects of the polyphenol resveratrol include an ability to bolster endogenous antioxidant defenses, modulate nitric oxide synthesis, and promote vasodilation, which thereby improves blood flow. Resveratrol may therefore modulate aspects of brain function in humans.

OBJECTIVE

The current study assessed the effects of oral resveratrol on cognitive performance and localized cerebral blood flow variables in healthy human adults.

DESIGN

In this randomized, double-blind, placebo-controlled, crossover study, 22 healthy adults received placebo and 2 doses (250 and 500 mg) of trans-resveratrol in counterbalanced order on separate days. After a 45-min resting absorption period, the participants performed a selection of cognitive tasks that activate the frontal cortex for an additional 36 min. Cerebral blood flow and hemodynamics, as indexed by concentration changes in oxygenated and deoxygenated hemoglobin, were assessed in the frontal cortex throughout the posttreatment period with the use of near-infrared spectroscopy. The presence of resveratrol and its conjugates in plasma was confirmed by HPLC after the same doses in a separate cohort (n = 9).

RESULTS

Resveratrol administration resulted in dose-dependent increases in cerebral blood flow during task performance, as indexed by total concentrations of hemoglobin. There was also an increase in deoxyhemoglobin after both doses of resveratrol, which suggested enhanced oxygen extraction, that became apparent toward the end of the 45-min absorption phase and was sustained throughout task performance. Cognitive function was not affected. Resveratrol metabolites were present in plasma throughout the cognitive task period.

CONCLUSION

These results showed that single doses of orally administered resveratrol can modulate cerebral blood flow variables.

A new evaluation method for +Gz tolerance with loratadine by using a near-infrared spectroscopy

BACKGROUND

Loratadine (Claritin), an over-the-counter antihistamine in U.S. and UK, is acceptable for use without adverse side effects by aircrew with mild or moderate allergic or other situations requiring an antihistamine. Although +Gz (head to foot direction) tolerance testing for aircrew with loratadine has not been documented in the published literature, it is commonly accepted that loratadine dose not effect +Gz tolerance. The purpose of this study was to offer and validate a new evaluation method for +Gz tolerance testing with loratadine by using a near-infrared spectroscopy (NIRS).

METHODS

A double-blind, placebo-controlled, randomized, crossover protocol was used to administer 10 mg of loratadine or placebo in nine healthy subjects. The subjects didn't wear anti-G suit. The +Gz exposure profiles consisted of, in series, a gradual onset ran (0.1 G.sec-1) to the subject's visual end-point (peripheral light loss) or loss of consciousness (GLOC), and rapid onset run (1.0 G.sec-1) to the subject's same end-point. In this study, G-level tolerance was defined as the +Gz level at visual end-point and/or at GLOC. As a subject's G-duration tolerance, we measured the total time (seconds) during rapid onset run. Otherwise, to confirm the effect of loratadine on +Gz tolerance, we measured the cerebral NIRS variables (hemoglobin concentration changes and tissue oxygenation index) as a new quantitative method for +Gz tolerance during a centrifuge experiments.

RESULTS

No significant differences were observed in +Gz tolerance (+Gz level, duration time and NIRS variables) between subjects taking loratadine and placebo.

CONCLUSION

Our results demonstrate that loratadine has no detectable effect on +Gz tolerance by using a new method with cerebral NIRS variables and the traditional method with +Gz level and duration time. This study represents the first use of a quantitative parameter such as cerebral NIRS variables to assess the effects of a drug on acceleration tolerance.