Influence of B vitamins on binding properties of serotonin receptors in the CNS of rats

How Do Anger and Impulsivity Impact Fast-Food Consumption in Transitional Age Youth?

Introduction

Consumption of fast food has been linked to psychiatric distress, violent behaviors, and impulsivity in adolescents. The relationship between eating fast food, anger, and impulsivity has not been widely investigated. The National Consortium on Alcohol and Neurodevelopment in Adolescence community-based cohort consists of 831 youth, half at elevated risk factors for substance use disorders during adolescence, followed annually.

Methods

Impulsivity using Urgency, Premeditation, Perseverance, and Sensation Seeking Impulsive Behavior scale from annual assessments was examined in relation to self-reported fast-food consumption frequency and mobile application questions of anger. This study tested the hypotheses that youth anger may be predicted by fast-food consumption frequency and impulsivity using multiple regression, in addition to whether adolescent fast-food consumption frequency may be predicted by anger and impulsivity.

Results

Among youth, higher anger levels and impulsivity predicted greater frequency of fast-food consumption, and greater fast-food consumption frequency and impulsivity predicted higher anger levels.

Conclusions

This study's longitudinal findings are consistent with those of other studies that have found fast-food consumption and anger associated with impulsivity and also reveal a bidirectional link between anger and fast-food consumption. These results may point attention to food selection considerations for those at risk of anger and poorer psychiatric outcomes.

A Randomized Control Trial of Dexketoprofen/Vitamin B (Thiamine, Pyridoxine and Cyanocobalamin) Fixed-Dose Combination in Post-Traumatic Grade I-II Cervical Sprains

BACKGROUND

Musculoskeletal disorders are an important cause of work absence. Clinical practice guidelines recommend nonsteroidal anti-inflammatory drugs (NSAIDs) for grade I-II cervical sprains. The combination of thiamine + pyridoxine + cyanocobalamin vitamins has been used, alone and in combination with NSAIDs, for pain and inflammation in musculoskeletal disorders.

OBJECTIVE

The objective of this study was to demonstrate the analgesic synergy of dexketoprofen, and the combination of vitamins thiamine + pyridoxine + cyanocobalamin in a fixed-dose combination (FDC) for the treatment of acute pain caused by grade I-II cervical sprains.

METHODS

We conducted a multicentre, prospective, randomized, double-blind, phase IIIb clinical study comparing two treatment groups: (1) dexketoprofen 25 mg/vitamin B (thiamine 100 mg, pyridoxine 50 mg and cyanocobalamin 0.50 mg) in an FDC (two or more active ingredients combined in a single dosage form) versus (2) dexketoprofen 25 mg monotherapy (single drug to treat a particular disease), one capsule or tablet orally, every 8 h for 7 days. Final mean, average change, and percentage change in pain perception (measured using a visual analogue scale [VAS]) were compared with baseline between groups. A p value < 0.05 was considered statistically significant. Analyses were conducted using SPSS software, v.29.0.

RESULTS

A statistically significant reduction in pain intensity was observed from the third day of treatment with the FDC compared with monotherapy (- 3.1 ± - 1.5 and - 2.6 ± - 1.1 cm, respectively) measured using the VAS (p = 0.011). Regarding the degree of disability, using the Northwick Park Neck Pain Questionnaire (NPQ), statistical difference was observed for the final measurement (7.5%, interquartile range [IQR] 2.5, 10.5; vs. 7.9%, IQR 5.0, 13.8; p = 0.028). A lower proportion of adverse events was reported when using the FDC.

CONCLUSIONS

The FDC of dexketoprofen/thiamine + pyridoxine + cyanocobalamin vitamins demonstrated superior efficacy and a better safety profile compared with dexketoprofen monotherapy for pain treatment in patients with grade I-II cervical sprains.

CLINICAL TRIALS REGISTRATION

NCT05001555, registered 29 July 2021 ( https://clinicaltrials.gov/study/NCT05001555 ).

Mechanisms of action of vitamin B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) in pain: a narrative review

Pain is a complex sensory and emotional experience with nociceptive, nociplastic, and neuropathic components. An involvement of neurotropic B vitamins (B1 - thiamine, B6 - pyridoxine, and B12 - cyanocobalamin) as modulators of inflammation and pain has been long discussed. New evidence suggests their therapeutic potential in different pain conditions. In this review, we discuss the main role of neurotropic B vitamins on different nociceptive pathways in the nervous system and to describe their analgesic action mechanisms. The performed literature review showed that, through different mechanisms, these vitamins regulate several inflammatory and neural mediators in nociceptive and neuropathic pain. Some of these processes include aiming the activation of the descending pain modulatory system and in specific intracellular pathways, anti-inflammatory, antioxidative and nerve regenerative effects. Moreover, recent data shows the antinociceptive, antiallodynic, and anti-hyperalgesic effects of the combination of these vitamins, as well as their synergistic effects with known analgesics. Understanding how vitamins B1, B6, and B12 affect several nociceptive mechanisms can therefore be of significance in the treatment of various pain conditions.

A Latin American consensus meeting on the essentials of mixed pain

OBJECTIVES

The term "mixed pain" has been established when a mixture of different pain components (e.g. nociceptive, neuropathic, and nociplastic) are present. It has gained more and more acceptance amongst pain experts worldwide, but many questions around the concept of mixed pain are still unsolved. The sensation of pain is very personal. Cultural, social, personal experiences, idiomatic, and taxonomic differences should be taken into account during pain assessment. Therefore, a Latin American consensus committee was formed to further elaborate the essentials of mixed pain, focusing on the specific characteristics of the Latin American population.

METHODS

The current approach was based on a systematic literature search and review carried out in Medline. Eight topics about the definition, diagnosis, and treatment of mixed pain were discussed and voted for by a Latin American consensus committee and recommendations were expressed.

RESULTS

At the end of the meeting a total of 14 voting sheets were collected. The full consensus was obtained for 21 of 25 recommendations (15 strong agreement and 6 unanimous agreement) formulated for the above described 8 topics (7 of the 8 topics had for all questions at least a strong agreement - 1 topic had no agreement for all 4 questions).

CONCLUSION

In a subject as complex as mixed pain, a consensus has been reached among Latin American specialists on points related to the definition and essence of this pain, its diagnosis and treatment. Recommendations for diagnosis and treatment of mixed pain in Latin America were raised.

Possible involvement of NO-sGC-cGMP signaling in the antidepressant like effect of pyridoxine in mice

The present study was designed to determine the antidepressant like effect of pyridoxine in mice. Pyridoxine (12.5, 25 and 50 mg/kg, i.p.) was administered to the mice and depression related behavioral and neurochemical alterations were determined. It was observed that pyridoxine (50 mg/kg, i.p.) treatment decreased the immobility period in tail suspension test (TST) and forced swim test (FST) significantly as compared to control. Pyridoxine (50 mg/kg, i.p.) treatment increased the level of serotonin (5-HT) and decreased the level of nitrite in the brain of mice significantly as compared to control. Pyridoxine thus confer antidepressant like effect by increasing the level of 5-HT and by decreasing the level of nitrite in the brain of mice. Further the influence of nitric oxide (NO)/ soluble guanylate cyclase (sGC)/ cyclic guanosine monophosphate (cGMP) in antidepressant-like effect of pyridoxine was studied. It was observed that the pretreatment of NO donor (i.e. L-Arginine) and cGMP modulator (i.e. sildenafil) counteracted while the pretreatment of NO/sGC inhibitor (i.e. methylene blue) potentiated the effect of pyridoxine in TST and FST. Pretreatment of NO donor did not influence, pretreatment of NO/sGC inhibitor decreased while the pretreatment of cGMP modulator increased the level of brain nitrite in pyridoxine treated mice. Further the pretreatment of NO donor and cGMP modulator decreased while the pretreatment of NO/sGC inhibitor increased the level of brain serotonin in pyridoxine treated mice. Pyridoxine thus exerted antidepressant like effect and NO-sGC-cGMP signaling modulated the antidepressant like effect of pyridoxine in mice.

[Role of B vitamins, thiamine, pyridoxine, and cyanocobalamin in back pain and other musculoskeletal conditions: a narrative review]

Low back pain, as well as other musculoskeletal disorders (neck pain, osteoarthritis, etc.), are a very frequent cause of consultation both in primary care and in other hospital specialties and are usually associated with high functional and work disability. Acute low back pain can present different nociceptive, neuropathic and nonciplastic components, which leads to consider it as a mixed type pain. The importance of the concept of mixed pain is due to the fact that the symptomatic relief of these pathologies requires a multimodal therapeutic approach to various pharmacological targets. The antinociceptive role of the B vitamin complex has been recognized for several decades, specifically the combination of Thiamine, Pyridoxine and Cyanocobalamin (TPC). Likewise, there is accumulated evidence that indicates an adjuvant analgesic action in low back pain. The aim of the present review is to present the existing evidence and the latest findings on the therapeutic effects of the TPC combination in low back pain. Likewise, some of the most relevant mechanisms of action involved that can explain these effects are analyzed. The reviewed evidence indicates that the combined use of PCT has an adjuvant analgesic effect in mixed pain, specifically in low back pain and other musculoskeletal disorders with nociceptive and neuropathic components. This effect can be explained by an anti-inflammatory, antinociceptive, neuroprotective and neuromodulatory action of the TPC combination on the descending pain system.

The Microbiome-Gut-Brain Axis and Resilience to Developing Anxiety or Depression under Stress

Episodes of depression and anxiety commonly follow the experience of stress, however not everyone who experiences stress develops a mood disorder. Individuals who are able to experience stress without a negative emotional effect are considered stress resilient. Stress-resilience (and its counterpart stress-susceptibility) are influenced by several psychological and biological factors, including the microbiome-gut-brain axis. Emerging research shows that the gut microbiota can influence mood, and that stress is an important variable in this relationship. Stress alters the gut microbiota and plausibly this could contribute to stress-related changes in mood. Most of the reported research has been conducted using animal models and demonstrates a relationship between gut microbiome and mood. The translational evidence from human clinical studies however is rather limited. In this review we examine the microbiome-gut-brain axis research in relation to stress resilience.

Synergistic interaction between B vitamins and statins to counter nociception in rats

Evidence suggests that the antinociceptive activity of various drugs can be increased when administered in combination with B vitamins (BVs). The aim of this study was to examine the potential interaction between statins and BVs to counter nociception, the latter measured by the formalin test. Rats were orally administered atorvastatin (1, 3, 10 and 30 mg/kg), pravastatin (1, 3, 10 and 30 mg/kg), rosuvastatin (1, 3, 10 and 30 mg/kg), BVs (31, 56, 100 and 180 mg/kg) or calculated combinations of BVs with each drug. The effective dose 30 (ED₃₀ ) was calculated for each statin and BVs and subjected to isobolographic analysis, thus finding the ED₃₀ of the combinations. The antinociceptive experimental ED₃₀ values for BVs administered with atorvastatin, pravastatin or rosuvastatin were 1.53 ± 0.38, 6.74 ± 0.04 and 4.26 ± 0.39, respectively, being lower (p < .05) than the corresponding theoretical ED₃₀ : 28.02 ± 2.20, 28.17 ± 2.20 and 29.86 ± 2.21. Since BVs likely boost the antinociceptive effect of statins, these combinations could possibly be advantageous in pain management.

The Role of the Gut Microbiota in Dietary Interventions for Depression and Anxiety

There is emerging evidence that an unhealthy dietary pattern may increase the risk of developing depression or anxiety, whereas a healthy dietary pattern may decrease it. This nascent research suggests that dietary interventions could help prevent, or be an alternative or adjunct therapy for, depression and anxiety. The relation, however, is complex, affected by many confounding variables, and is also likely to be bidirectional, with dietary choices being affected by stress and depression. This complexity is reflected in the data, with sometimes conflicting results among studies. As the research evolves, all characteristics of the relation need to be considered to ensure that we obtain a full understanding, which can potentially be translated into clinical practice. A parallel and fast-growing body of research shows that the gut microbiota is linked with the brain in a bidirectional relation, commonly termed the microbiome-gut-brain axis. Preclinical evidence suggests that this axis plays a key role in the regulation of brain function and behavior. In this review we discuss possible reasons for the conflicting results in diet-mood research, and present examples of areas of the diet-mood relation in which the gut microbiota is likely to be involved, potentially explaining some of the conflicting results from diet and depression studies. We argue that because diet is one of the most significant factors that affects human gut microbiota structure and function, nutritional intervention studies need to consider the gut microbiota as an essential piece of the puzzle.

Associations between Dietary Pattern and Depression in Korean Adolescent Girls

STUDY OBJECTIVE

Dietary patterns are important for the physical and psychological development of adolescent girls. The purpose of the present study was to evaluate the relationship between dietary patterns and depression in this population.

DESIGN, SETTING, AND POPULATION

We conducted a case-control study in a tertiary university hospital of 849 girls aged 12 to 18 years.

METHODS

The study was conducted from April 2011 to December 2012. Participants were identified as having depression if they had scores greater than 16 on the Korean version of the Beck Depression Inventory. Data were obtained using validated Korean-language questionnaires.

MAIN OUTCOME MEASURES

The subjects' usual dietary patterns during the past 12 months were assessed using the Food Frequency Questionnaire published by the Korean Health and Nutrition Examination Survey.

RESULTS

Among the 849 enrolled volunteers, 116 were identified as having depressive symptoms. The mean age of the participants was 15.0 ± 1.5 years. The prevalence of girls diagnosed with depression was 13.6%. Multivariate adjusted regression analysis demonstrated that the risk of depression was significantly positively associated with the consumption of instant and processed foods and negatively associated with the intake of green vegetables and 1 to 3 servings/day of fruits, after adjusting for energy intake and menstrual regularity. Additionally, depression was negatively associated with intake of fiber, β-carotene, vitamin B6, vitamin E, vitamin C, potassium, zinc, folate, iron, and copper after adjusting for confounding variables.

CONCLUSION

Consumption of fast foods including ramen noodles, hamburger, pizza, fried food, and other processed foods was associated with increased risk of depression in adolescent girls. Thus, caution is required regarding dietary choices in this population.

Synergistic interactions between the antinociceptive effect of Rhodiola rosea extract and B vitamins in the mouse formalin test

AIM

In this study, the pharmacological interactions between a Rhodiola rosea ethanol extract and B-vitamins such as thiamine (B1), riboflavine (B2), pyridoxine (B6), cyanocobalamin (B12) and a mixture of vitamins B1+B6+B12 was investigated in the mouse formalin test.

METHODS

Individual dose response curves of the Rhodiola rosea ethanol extract, as well as B-vitamins alone or in a mixture were evaluated in mice in which nociception was induced with 2% formalin intraplantarly. The antinociceptive mechanisms of the Rhodiola rosea were investigated by exploring the role of the opioid and serotonin receptors and the nitric oxide pathway. Isobolographic analysis was used to evaluate the pharmacological interactions between the Rhodiola rosea ethanol extract and each B-vitamin individually or the mixture of vitamins B1+B6+B12 by using the ED30 and a fixed 1:1 ratio combination.

RESULTS

Administration of the Rhodiola rosea extract alone or in combination with all of the vitamins produced a significant and dose-dependent antinociceptive response. The antinociceptive effect of the Rhodiola rosea extract (ED50=81 mg/kg, p.o.) was significant and reverted in the presence of antagonists of the 5-HT1A, GABA/BDZs and opioid receptors and by blocking mediators of the nitric oxide/cGMP/K(+) channels pathway. Isobolograms demonstrate that all of the combinations investigated in this study produced a synergistic interaction experimental ED30 values were significantly smaller than those calculated theoretically.

CONCLUSIONS

These results provide evidence that a Rhodiola rosea ethanol extract in combination with B-vitamins produces a significant diminution in the nociceptive response in a synergistic manner, which is controlled by various mechanisms. These findings could aid in the design of clinical studies and suggest that these combinations could be applied for pain therapy.

Early infant exposure to excess multivitamin: a risk factor for autism?

Autism, a neurodevelopmental disorder that affects boys more than girls, is often associated with altered levels of monoamines (serotonin and catecholamines), especially elevated serotonin levels. The monoamines act as both neurotransmitters and signaling molecules in the gastrointestinal and immune systems. The evidence related to monoamine metabolism may be summarized as follows: (i) monoamine neurotransmitters are enzymatically degraded/inactivated by three mechanisms: oxidative deamination, methylation, and sulfation. The latter two are limited by the supply of methyl groups and sulfate, respectively. (ii) A decrease in methylation- and sulfation-mediated monoamine inactivation can be compensated by an increase in the oxidative deamination catalyzed by monoamine oxidase, an X-linked enzyme exhibiting higher activity in females than in males. (iii) Vitamins can, on one hand, facilitate the synthesis of monoamine neurotransmitters and, on the other hand, inhibit their inactivation by competing for methylation and sulfation. Therefore, we postulate that excess multivitamin feeding in early infancy, which has become very popular over the past few decades, may be a potential risk factor for disturbed monoamine metabolism. In this paper, we will focus on the relationship between excess multivitamin exposure and the inactivation/degradation of monoamine neurotransmitters and its possible role in the development of autism.

Effect of diet on serotonergic neurotransmission in depression

Depression is characterized by sadness, purposelessness, irritability, and impaired body functions. Depression causes severe symptoms for several weeks, and dysthymia, which may cause chronic, low-grade symptoms. Treatment of depression involves psychotherapy, medications, or phototherapy. Clinical and experimental evidence indicates that an appropriate diet can reduce symptoms of depression. The neurotransmitter, serotonin (5-HT), synthesized in the brain, plays an important role in mood alleviation, satiety, and sleep regulation. Although certain fruits and vegetables are rich in 5-HT, it is not easily accessible to the CNS due to blood brain barrier. However the serotonin precursor, tryptophan, can readily pass through the blood brain barrier. Tryptophan is converted to 5-HT by tryptophan hydroxylase and 5-HTP decarboxylase, respectively, in the presence of pyridoxal phosphate, derived from vitamin B(6). Hence diets poor in tryptophan may induce depression as this essential amino acid is not naturally abundant even in protein-rich foods. Tryptophan-rich diet is important in patients susceptible to depression such as certain females during pre and postmenstrual phase, post-traumatic stress disorder, chronic pain, cancer, epilepsy, Parkinson's disease, Alzheimer's disease, schizophrenia, and drug addiction. Carbohydrate-rich diet triggers insulin response to enhance the bioavailability of tryptophan in the CNS which is responsible for increased craving of carbohydrate diets. Although serotonin reuptake inhibitors (SSRIs) are prescribed to obese patients with depressive symptoms, these agents are incapable of precisely regulating the CNS serotonin and may cause life-threatening adverse effects in the presence of monoamine oxidase inhibitors. However, CNS serotonin synthesis can be controlled by proper intake of tryptophan-rich diet. This report highlights the clinical significance of tryptophan-rich diet and vitamin B(6) to boost serotonergic neurotransmission in depression observed in various neurodegenerative diseases. However pharmacological interventions to modulate serotonergic neurotransmission in depression, remains clinically significant. Depression may involve several other molecular mechanisms as discussed briefly in this report.

Effect of diclofenac with B vitamins on the treatment of acute pain originated by lower-limb fracture and surgery

The aim of this study was to compare the efficacy of diclofenac, for the treatment of acute pain originated by lower-limb fracture and surgery, with that of diclofenac plus B vitamins. This was a single-center, prospective, randomized, and double-blinded clinical trial. Patients with lower-limb closed fractures rated their pain on a 10 cm visual analog scale (VAS). Patients were then randomized to receive diclofenac or diclofenac plus B vitamins (thiamine, pyridoxine, and cyanocobalamin) intramuscularly twice daily. Patient evaluations of pain intensity were recorded throughout two periods: twenty-four hours presurgery and twenty-four hours postsurgical. One hundred twenty-two patients completed the study. The subjects' assessments of limb pain on the VAS showed a significant reduction from baseline values regardless of the treatment group. Diclofenac plus B vitamins combination was more effective to reduce the pain than diclofenac alone. The results showed that the addition of B vitamins to diclofenac increased its analgesic effect. The novelty of this paper consists in that diclofenac and diclofenac plus B vitamins were useful for treatment of acute pain originated by lower-limb fracture and surgery.

Vitamins and neural and cognitive developmental outcomes in children

The role of vitamin status in the development of the brain and the subsequent functioning of the brain was considered. There are data with a range of vitamins, from animal studies and human studies in developing countries, suggesting that a clinical deficiency during the critical period when the brain is developing causes permanent damage. To date there is, however, with the exception of cases of clinical deficiency such as those that might be associated with a vegan diet, little evidence that variations in the diet of those living in industrialised countries have a lasting developmental influence. Similarly, later in life clinical deficiencies of various vitamins disrupt cognition although there is to date limited evidence that variations in the intake of single vitamins in industrialised societies influence functioning. It may well be, however, unreasonable to expect that vitamins examined in isolation will be associated with differences in cognitive functioning. The output of the brain reflects millions of metabolic processes, each potentially susceptible to any of a range of vitamins. A diet poor in one respect is likely to be poor in other respects as well. As such, the preliminary reports in double-blind placebo-controlled trials that aspects of cognition and behaviour respond to supplementation with multi-micronutrients may indicate the way forward.

Alterations in hippocampal serotonergic and INSR function in streptozotocin induced diabetic rats exposed to stress: neuroprotective role of pyridoxine and Aegle marmelose

Diabetes and stress stimulate hippocampal 5-HT synthesis, metabolism and release. The present study was carried out to find the effects of insulin, Aegle marmelose alone and in combination with pyridoxine on the hippocampal 5-HT, 5-HT_2A receptor subtype, gene expression studies on 5-HT_2A, 5-HTT, INSR, immunohistochemical studies and elevated plus maze in streptozotocin induced diabetic rats. 5-HT content showed a significant decrease (p < 0.001) and a significant increase (p < 0.001) in 5-HIAA in hippocampus of diabetic rats compared to control. 5-HT receptor binding parameters B_max and K_d showed a significant decrease (p < 0.001) whereas 5-HT_2A receptor binding parameters B_max showed a significant decrease (p < 0.001) with a significant increase (p < 0.05) in K_d in hippocampus of diabetic rats compared to control. Gene expression studies of 5-HT_2A, 5-HTT and INSR in hippocampus showed a significant down regulation (p < 0.001) in diabetic rats compared to control. Pyridoxine treated in combination with insulin and A. marmelose to diabetic rats reversed the 5-HT content, B_max , K_d of 5-HT, 5-HT_2A and gene expression of 5-HT_2A, 5-HTT and INSR in hippocampus to near control. The gene expression of 5-HT_2A and 5-HTT were confirmed by immunohistochemical studies. Behavioural studies using elevated plus maze showed that serotonin through its transporter significantly increased (p < 0.001) anxiety-related traits in diabetic rats which were corrected by combination therapy. Our results suggest that pyridoxine treated in combination with insulin and A. marmelose has a role in the regulation of insulin synthesis and release, normalising diabetic related stress and anxiety through hippocampal serotonergic function. This has clinical significance in the management of diabetes.

Transient protective effect of B-vitamins in experimental epilepsy in the mouse brain

The regulation of programmed cell death in the nervous system of vertebrates is a complex mechanism aimed to remove superfluous or damaged cells. Epileptic seizures can lead to an activation of pathways resulting in neuronal cell death. B-vitamins might have a neuroprotective potential reducing cell death following appropriate stimulation. Here, the role of the B-vitamins B(1) (thiamine), B(6) (pyridoxine), and B(12) (cobalamine) was investigated in a mouse model of experimental epilepsy induced by kainate. B-vitamin pre-treated animals showed a significantly reduced epileptic score during the first 15 min after kainate injection. The molecular response to kainate showed a bi-phased time course with early induction of Bcl-2 expression within 12 h and a second induction after 7 days of kainate exposure. B-vitamin pre-treatment resulted in significant higher Bcl-2 expression in control animals (no kainate) and at 12 h within the early phase. Bcl-2 expression was not affected by B-vitamins within the second phase. BAX expression was not significantly influenced during the whole experiment. Three days after kainate stimulation, the number of TdT-mediated dUTP-biotin nick end labeling-positive cells in the hippocampal region was lower in B-vitamin-treated animals. Therefore, B-vitamin pre-treatment may attenuate the response to epileptic stimulation.

The impact of diet on anti-social, violent and criminal behaviour

The role of diet in anti-social behaviour was considered, paying particular attention to double-blind placebo-controlled trials. Meta-analysis of five well-designed studies found that elimination diets reduced hyperactivity-related symptoms, producing a summary standardized mean difference (SSMD) of 0.80 (95% CI 0.41-1.19). The picture was of children potentially responding to a wide range of food items although the pattern was individual to the child. Supplementation with poly-unsaturated fatty acids decreased violence (SSMD -0.61, 95% CI -0.83 to -0.39) although there was no evidence of an influence on hyperactivity. Three well-designed studies have reported that vitamin/mineral supplementation reduced anti-social behaviour. There are also findings of an association between a tendency to develop low blood glucose and aggression. Many responses to diet were idiosyncratic and involved a wide range of foods interacting with individual differences in physiology. Reactions were not observed in all members of groups chosen because they share a common behavioural designation or diagnosis.

Thiamine and Cyanocobalamin Relieve Neuropathic Pain in Rats: Synergy with Dexamethasone

Treatment of neuropathic pain is an area of largely unmet medical need. Therefore, this pain may require the development of novel drug entities. In the search for alternatives, B vitamins have been found to be a clinically useful pharmacological tool for patients with neuropathic pain. However, preclinical studies supporting this use are lacking. In this study, we assessed the possible antiallodynic effects of thiamine, pyridoxine, and cyanocobalamin as well as dexamethasone and their combination on spinal nerve ligation induced allodynia. Sub cutaneous administration of thiamine (75-600 mg/kg), pyridoxine (75-600 mg/kg), cyanocobalamin(0.75-6 mg/kg), and dexamethasone (4-32 mg/kg) significantly reduced tactile allodynia in rats. Maximal antiallodynic effects were reached with 600 mg/kg of thiamine (approximately 58%), 600 mg/kg of pyridoxine (approximately 22%), 6 mg/kg of cyanocobalamin (approximately 73%), and 32 mg/kg of dexamethasone (approximately 68%). Since a small antiallodynic effect was observed with pyridoxine, this drug was not further analyzed in the combinations. Coadministration of thiamine or cyanocobalamin and dexamethasone remarkably reduced spinal nerve ligation induced allodynia (approximately 90%), showing a synergistic interaction between either thiamine or cyanocobalamin and dexamethasone. Our data indicate that thiamine and pyridoxine as well as the combination of B vitamins and dexamethasone are able to reduce tactile allodynia in rats and suggest the possible clinical use of these drugs in the treatment of neuropathic pain in human beings.

Elevated sympathetic activity may promote insulin resistance syndrome by activating alpha-1 adrenergic receptors on adipocytes

An excess of free intracellular calcium can reduce the efficiency of insulin-mediated glucose transport by blocking the dephosphorylation of GLUT-4. Classical isoforms of protein kinase C (PKC) can interfere with insulin signalling via serine phosphorylation of IRS-1 and the insulin receptor. Parathyroid hormone (PTH), by activating phospholipase C-beta in adipocytes, can promote a sustained increase in intracellular free calcium in these cells, while also activating classical PKCs. This may rationalize the fact that insulin resistance is a typical feature of hyperparathyroidism, as well as epidemiological evidence that regular ingestion of dairy products or of ethanol--which down-regulates PTH secretion--reduces risk for insulin resistance syndrome and diabetes. Alpha-1 adrenergic receptors of adipocytes--like PTH receptors--also activate phospholipase C-beta, and thus have an effect analogous to PTH on intracellular free calcium and PKC activity in adipocytes. This suggests that, via activation of alpha-1 adrenergic receptors, increased sympathetic activity in adipose tissue may promote insulin resistance syndrome. In fact, measures which provoke increased sympathetic output--such as diuretic use and severe salt restriction--are known to compromise insulin sensitivity, whereas alpha-1 antagonist drugs, as well as drugs that act centrally to suppress sympathetic activity, typically have a favorable effect on insulin function. When insulin resistance syndrome is associated with elevated sympathetic activity--for example, in hypertensives who are obese or on diuretic therapy--measures which down-regulate sympathetic activity, or, more specifically, alpha-1 adrenergic activity, may be warranted. These include centrally acting imidazoline analogs (moxonidine, rilmenidine) and alpha-1 antagonists (doxazosin, prazosin). Taurine and high-dose pyridoxine may represent practical nutritional strategies for moderating elevated sympathetic activity, and exercise training and low-insulin-response diets may be useful in this regard as well.

Pyridoxine, regardless of serotonin levels, increases production of 5-hydroxytryptophan in rat brain

BACKGROUND

The aim of this study was to evaluate effects of pyridoxine and butylated hydroxytoluene (BHT) on lipid peroxidation and on levels of 5-hydroxytryptophan and serotonin.

METHODS

Thirty rats (30 days of age) were used in the survey, measuring levels of lipid peroxidation (TBARS), hemoglobin, 5-hydroxytryptophan (5-HTP), and serotonin (5-HT) after intraperitoneal (i.p.) injections of 4 and 10 mg/kg/day of pyridoxine HCl during 20 days and a single dose of 2 microM/kg (440 microg) of BHT.

RESULTS

Levels of TBARS and 5-HTP increased considerably (p <0.05) in all vitamin- and/or BHT-treated groups, and 5-HT increased partially (p <0.05) only in B(6) with or without BHT-treated groups compared with control group.

CONCLUSIONS

Results suggest that pyridoxine plays a role in tryptophan metabolism, increasing production of 5-HTP.

Micro-nutrient supplementation and the intelligence of children

A growing number of double-blind placebo-controlled studies have considered the influence of micro-nutrient supplementation on the intelligence of children. Earlier studies prevented the drawing of conclusions as they did not systematically approach the topic. However, over the last 10 years, a series of studies have compared the impact of supplementation on either verbal or non-verbal measures of intelligence. In 10 out of 13 studies a positive response has been reported, always with non-verbal measures, in at least a sub-section of the experimental sample. A selective response to non-verbal tests was predicted as they reflect basic biologically functioning that could be expected to be influenced by diet. The evidence is that not all children respond to supplementation, rather there is a minority who benefit, whose diet offers low amounts of micro-nutrients. Such observations are consistent with dietary surveys that typically report a sub-set of children with a low intake. The topic is at a very early stage and needs the clarification gained from a series of large-scale studies that consider children of a wide range of ages, dietary styles and social backgrounds.

High-dose pyridoxine as an 'anti-stress' strategy

Pyridoxine nutritional status has a significant and selective modulatory impact on central production of both serotonin and GABA - neurotransmitters which control depression, pain perception, and anxiety - owing to the fact that the decarboxylases which produce these neurotransmitters have a relatively low affinity for pyridoxal phosphate (PLP). Pyridoxine deficiency leads to increased sympathetic outflow and hypertension in rodents, possibly reflecting decreased central production of these neurotransmitters; conversely, supplemental pyridoxine lowers blood pressure in many animal models of hypertension, and there is preliminary evidence for antihypertensive activity in humans as well. Additionally, physiological levels of PLP interact with glucocorticoid receptors to down-regulate their activity. Thus, high-dose pyridoxine, by amplifying tissue levels of PLP, may be expected to have a favorable impact on certain dysphoric mental states, while diminishing sympathetic output and acting peripherally to blunt the physiological impact of corticosteroids. In light of growing evidence that chronic dysphoria, particularly when accompanied by hopelessness or cynicism, has a major negative impact on morbidity and mortality from a wide range of disorders, high intakes of pyridoxine may have the potential to improve prognosis in many individuals. With respect to cardiovascular health, reduction of homocysteine levels should contribute to this benefit. These predictions are consistent with recent epidemiology correlating plasma PLP levels with risk for vascular events and overall survival.

Dietary excess of vitamin B-6 affects the concentrations of amino acids in the caudate nucleus and serum and the binding properties of serotonin receptors in the brain cortex of rats

Vitamin B-6 is a cofactor in many reactions of nitrogen metabolism. Deficiency alters tissue amino acid concentrations but effects of excess vitamin B-6 have not been well described. We fed female rats (218 g, 7 per group) 1 (control), 10, 100, 175 or 250x) the National Research Council recommended level of pyridoxine HCl (7 mg/kg) for 10 wk and measured serum amino acids, amino acids and neurotransmitters in brain regions and the binding properties of serotonin receptors in the cerebral cortex using a ketanserin binding assay. Rats were decapitated, and unheparinized blood was obtained. In the caudate nucleus, concentrations of glutamate, threonine, taurine, methionine, gamma-amino-butyric acid and the sum of the essential amino acids in groups 10X and 100X were approximately 130 to 180% of control levels (P < 0.05); groups 1X, 175X and 250X were not different. A similar pattern was seen in the serum for serine, glycine, aspartate and ornithine; the latter two amino acids increased to over 200% of control in group 100X. In the ketanserin binding assay, both the antagonist binding affinity and the maximal number of binding sites were higher for group 100X than for 1X, 175X and 250X, and were higher for 10X than for 1X. Norepinephrine in the raphe nucleus followed a similar biphasic pattern. Excess dietary pyridoxine affected brain and serum concentrations of some amino acids and binding properties of cortical serotonin receptors in a biphasic pattern over the range of concentrations fed in this study.

Acute effects of vitamin B6 and fixed combinations of vitamin B1, B6 and B12 on nociceptive activity evoked in the rat thalamus: dose-response relationship and combinations with morphine and paracetamol

Nociceptive activity was elicited in neurones of the thalamus by supramaximal electrical stimulation of afferent C fibres in the sural nerve of rats under urethane anesthesia. The fixed combination of vitamin B1, B6, and B12 (Neurobion) as well as of vitamin B6 administered by i.p. injection dose-dependently reduced the evoked nociceptive activity. The ED50 of Neurobion is 4.6 ml/kg (at 100 min after injection) and that of vitamin B6 is 189 mg/kg (at 90 min after injection). The minimum effective doses of Neurobion and vitamin B6 are 0.5 ml/kg and 40 mg/kg, respectively. When Neurobion or vitamin B6 were given at their minimum effective doses, and the minimum effective doses of morphine (0.025 mg/kg) or paracetamol (5 mg/kg) were injected i.v. 80 min later, i.e., when the maximum effect of higher doses of Neurobion or vitamin B6 was about to develop, no supraadditive effect developed. It is concluded that the antinociceptive effect caused by a single injection of Neurobion is largely due to vitamin B6. Vitamin B12 may contribute to this effect, whereas vitamin B1 alone exhibited only a slight effect on nociception. Moreover, it appears that Neurobion produces its antinociceptive effect after a single injection and after repeated administration during several days by different mechanisms so that the effect of analgesic agents is not enhanced following a single injection of Neurobion but may be enhanced after repeated administration of the compound.