Ketogenic diet and behavior: insights from experimental studies.

As a journal page for full details. The ketogenic diet (KD) has been established as a treatment for epilepsy, but more recently it has been explored as an alternative or add-on therapy for many other diseases ranging from weight loss to neurological disorders. Animal models are widely used in studies investigating the therapeutic effects of the KD as well as underlying mechanisms. Especially in the context of neurological, psychiatric, and neurodevelopmental disorders essential endpoints are assessed by behavioral and motor tests. Here we summarized research evaluating the influence of the KD on cognition, depressive and anxiety-related behaviors, and social and nutritional behaviors of laboratory rodents. Each section contains a brief description of commonly used behavioral tests highlighting their limitations. Ninety original research articles, written in English, performed on mice or rats, providing measurement of blood beta-hydroxybutyrate (BHB) levels and behavioral evaluation were selected for the review. The majority of research performed in various disease models shows that the KD positively impacts cognition. Almost an equal number of studies report a reduction or no effect of the KD on depressive-related behaviors. For anxiety-related behaviors, the majority of studies show no effect. Despite the increasing use of the KD in weight loss and its appetite-reducing properties the behavioral evaluation of appetite regulation has not been addressed in preclinical studies. This review provides an overview of the behavioral effects of nutritional ketosis addressed to a broad audience of scientists interested in the KD field but not necessarily specializing in behavioral tests.

Cardiac status and atherosclerotic cardiovascular risk of convalescents after COVID-19 in Poland.

INTRODUCTION: The COVID­19 pandemic brought about cardiac complications and unfavorable lifestyle changes that may increase cardiovascular risk. OBJECTIVES: Our aim was to establish the cardiac status of convalescents several months after COVID­19, and the 10­year risk of fatal and nonfatal atherosclerotic cardiovascular disease (ASCVD) events, according to the Systemic Coronary Risk Estimation­2 (SCORE2) and SCORE2­Older Persons (OP) algorithms. PATIENTS AND METHODS: The study included 553 convalescents (mean [SD] age, 63.5 [10.26] years; 316 [57.1%] women), hospitalized at the Cardiac Rehabilitation Department, Ustron Health Resort, Poland. The history of cardiac complications, exercise capacity, blood pressure control, echocardiography, 24­hour Holter electrocardiogram recording, and laboratory workup were assessed. RESULTS: A total of 20.7% of men and 17.7% of women (P = 0.38) had cardiac complications during acute COVID­19, most often heart failure (10.7%), pulmonary embolism (3.7%), and supraventricular arrhythmias (6.3%). On average, 4 months after COVID­19 diagnosis, echocardiographic abnormalities were found in 16.7% of men and 9.7% of women (P = 0.1), and benign arrhythmias in 45.3% of men and 44% of women (P = 0.84). Preexisting ASCVD was reported in 21.8% of men and 6.1% of women (P <0.001). The median risk assessed by SCORE2/SCORE2­OP algorithms in apparently healthy people was high for the participants aged 40-49 years (3%; interquartile range [IQR], 2%-4%) and 50-69 years (8%; IQR, 5.3%-10%), and very high (20%; IQR, 15.5%-37%) for the participants aged 70 years and above. The SCORE2 risk in men aged over 70 years was higher than in women (P <0.001). CONCLUSIONS: Data collected in the convalescents indicate a relatively small number of cardiac problems that could be associated with a history of COVID­19 in either sex, and a high risk of ASCVD, especially in men.

Effect of Whole-Body Vibration Training on Selected Intrinsic Risk Factors in Women Aged 60+ at Fall Risk: A Randomized Controlled Trial.

The aim of the study was to determine whether Whole Body Vibration Training (WBVT) affects intrinsic risk factors for falls in women aged 60+ at fall risk. DESIGN: Randomized controlled clinical trial. Blinding was applied to the persons in charge of evaluating the intervention's clinical results and statistical analysis. METHODS: Forty-two women over 60 years old were randomly assigned to an experimental group (EG-12-week WBVT; n = 22) and a control group (CG-no additional physical activities; n = 20). Fear of falling was measured by the FES-I questionnaire, gait and dynamic balance using the Time-Up and Go test (TUG), aerobic endurance with the 6-Minute Walk Test (6MWT), and the functional strength of the lower body muscles with the 30-s Chair Stand Test (30SCST) at baseline and post-intervention. Additionally assayed were participants' blood concentrations of interleukin-6 (IL-6). RESULTS: The 12-week WBVT improves gait and balance (TUG, p = 0.009), exercise tolerance (6MWT, p = 0.001), and functional strength (30SCST; p = 0.027) but does not reduce the intensity of fear of falling (FES-I, p = 0.655) and the IL-6 serum concentration (p = 0.377). CONCLUSIONS: WBVT affects selected fall risk factors in women aged 60+ at fall risk.

Running from Stress: Neurobiological Mechanisms of Exercise-Induced Stress Resilience.

Chronic stress, even stress of a moderate intensity related to daily life, is widely acknowledged to be a predisposing or precipitating factor in neuropsychiatric diseases. There is a clear relationship between disturbances induced by stressful stimuli, especially long-lasting stimuli, and cognitive deficits in rodent models of affective disorders. Regular physical activity has a positive effect on the central nervous system (CNS) functions, contributes to an improvement in mood and of cognitive abilities (including memory and learning), and is correlated with an increase in the expression of the neurotrophic factors and markers of synaptic plasticity as well as a reduction in the inflammatory factors. Studies published so far show that the energy challenge caused by physical exercise can affect the CNS by improving cellular bioenergetics, stimulating the processes responsible for the removal of damaged organelles and molecules, and attenuating inflammation processes. Regular physical activity brings another important benefit: increased stress robustness. The evidence from animal studies is that a sedentary lifestyle is associated with stress vulnerability, whereas a physically active lifestyle is associated with stress resilience. Here, we have performed a comprehensive PubMed Search Strategy for accomplishing an exhaustive literature review. In this review, we discuss the findings from experimental studies on the molecular and neurobiological mechanisms underlying the impact of exercise on brain resilience. A thorough understanding of the mechanisms underlying the neuroprotective potential of preconditioning exercise and of the role of exercise in stress resilience, among other things, may open further options for prevention and therapy in the treatment of CNS diseases.

Cerebrocortical proteome profile of female rats subjected to the western diet and chronic social stress.

The energy-dense western diet significantly increases the risk of obesity, type 2 diabetes, cardiovascular episodes, stroke, and cancer. Recently more attention has been paid to the contribution of an unhealthy lifestyle on the development of central nervous system disorders. Exposure to long-lasting stress is one of the key lifestyle modifications associated with the increased prevalence of obesity and metabolic diseases. The main goal of the present study was to verify the hypothesis that exposure to chronic stress modifies alterations in the brain proteome induced by the western diet. Female adult rats were fed with the prepared chow reproducing the human western diet and/or subjected to chronic stress induced by social instability for 6 weeks. A control group of lean rats were fed with a standard diet. Being fed with the western diet resulted in an obese phenotype and induced changes in the serum metabolic parameters. The combination of the western diet and chronic stress exposure induced more profound changes in the rat cerebrocortical proteome profile than each of these factors individually. The down-regulation of proteins involved in neurotransmitter secretion (Rph3a, Snap25, Syn1) as well as in learning and memory processes (Map1a, Snap25, Tnr) were identified, while increased expression was detected for 14-3-3 protein gamma (Ywhag) engaged in the modulation of the insulin-signaling cascade in the brain. An analysis of the rat brain proteome reveals important changes that indicate that a combination of the western diet and stress exposure may lead to impairments of neuronal function and signaling.

Effects of Simultaneous Exposure to a Western Diet and Wheel-Running Training on Brain Energy Metabolism in Female Rats.

BACKGROUND: In the pathogenesis of central nervous system disorders (e.g., neurodegenerative), an important role is attributed to an unhealthy lifestyle affecting brain energy metabolism. Physical activity in the prevention and treatment of lifestyle-related diseases is getting increasing attention. METHODS: We performed a series of assessments in adult female Long Evans rats subjected to 6 weeks of Western diet feeding and wheel-running training. A control group of lean rats was fed with a standard diet. In all experimental groups, we measured physiological parameters (animal weights, body composition, serum metabolic parameters). We assessed the impact of simultaneous exposure to a Western diet and wheel-running on the cerebrocortical protein expression (global proteomic profiling), and in the second part of the experiment, we measured the cortical levels of protein related to brain metabolism (Western blot). RESULTS: Western diet led to an obese phenotype and induced changes in the serum metabolic parameters. Wheel-running did not reduce animal weights or fat mass but significantly decreased serum glucose level. The global proteome analysis revealed that the altered proteins were functionally annotated as they were involved mostly in metabolic pathways. Western blot analysis showed the downregulation of the mitochondrial protein-Acyl-CoA dehydrogenase family member 9, hexokinase 1 (HK1)-enzyme involved in principal glucose metabolism pathways and monocarboxylate transporter 2 (MCT2). Wheel-running reversed this decline in the cortical levels of HK1 and MCT2. CONCLUSION: The cerebrocortical proteome is affected by a combination of physical activity and Western diet in female rats. An analysis of the cortical proteins involved in brain energy metabolism provides a valuable basis for the deeper investigation of changes in the brain structure and function induced by simultaneous exposure to a Western diet and physical activity.

Differential Response of Hippocampal and Cerebrocortical Autophagy and Ketone Body Metabolism to the Ketogenic Diet.

Experimental and clinical data support the neuroprotective properties of the ketogenic diet and ketone bodies, but there is still a lot to discover to comprehensively understand the underlying mechanisms. Autophagy is a key mechanism for maintaining cell homeostasis, and therefore its proper function is necessary for preventing accelerated brain aging and neurodegeneration. Due to many potential interconnections, it is possible that the stimulation of autophagy may be one of the mediators of the neuroprotection afforded by the ketogenic diet. Recent studies point to possible interconnections between ketone body metabolism and autophagy. It has been shown that autophagy is essential for hepatic and renal ketogenesis in starvation. On the other hand, exogenous ketone bodies modulate autophagy both in vitro and in vivo. Many regional differences occur between brain structures which concern i.e., metabolic responses and autophagy dynamics. The aim of the present study was to evaluate the influence of the ketogenic diet on autophagic markers and the ketone body utilizing and transporting proteins in the hippocampus and frontal cortex. C57BL/6N male mice were fed with two ketogenic chows composed of fat of either animal or plant origins for 4 weeks. Markers of autophagosome formation as well as proteins associated with ketolysis (BDH1-3-hydroxybutyrate dehydrogenase 1, SCOT/OXCT1-succinyl CoA:3-oxoacid CoA transferase), ketone transport (MCT1-monocarboxylate transporter 1) and ketogenesis (HMGCL, HMGCS2) were measured. The hippocampus showed a robust response to nutritional ketosis in both changes in the markers of autophagy as well as the levels of ketone body utilizing and transporting proteins, which was also accompanied by increased concentrations of ketone bodies in this brain structure, while subtle changes were observed in the frontal cortex. The magnitude of the effects was dependent on the type of ketogenic diet used, suggesting that plant fats may exert a more profound effect on the orchestrated upregulation of autophagy and ketone body metabolism markers. The study provides a foundation for a deeper understanding of the possible interconnections between autophagy and the neuroprotective efficacy of nutritional ketosis.

Inflammaging - contributing mechanisms and cellular signaling pathways / Zapalenie starcze - mechanizmy i szlaki sygnalowe.

Aging is a multifunctional process which is characterized by many changes on molecular, cellular and tissue levels. The chronic, sterile and low-grade inflammation process, that occurs during aging is referred to as 'inflammaging'. Inflammaging is mentioned as a risk factor for the onset and progression of chronic diseases, not only age-related. Inflammaging contributes to increased morbidity and mortality in elderly individuals, and also affects the lifespan and quality of life. Cell senescence and disturbances in the regulation of inflammasome activation, mitochondrial function, autophagy and mitophagy, ubiquitin-proteasome system and the response to DNA damage contribute to the development of inflammaging. The above processes interact with each other and are modulated by signaling pathways involved in the regulation of the inflammatory response, i.e. NF-kB, mTOR, RIG-I, Notch, TGF-b, Ras pathways, and regulation of sirtuin activity. The aim of the study is to present the processes and signaling pathways underlying inflammaging, including clinical and experimental studies.

Upregulation of hepatic autophagy under nutritional ketosis.

Many of the metabolic effects evoked by the ketogenic diet mimic the actions of fasting and the benefits of the ketogenic diet are often attributed to these similarities. Since fasting is a potent autophagy inductor in vivo and in vitro it has been hypothesized that the ketogenic diet may upregulate autophagy. The aim of the present study was to provide a comprehensive evaluation of the influence of the ketogenic diet on the hepatic autophagy. C57BL/6N male mice were fed with two different ketogenic chows composed of fat of either animal or plant origin for 4 weeks. To gain some insight into the time frame for the induction of autophagy on the ketogenic diet, we performed a short-term experiment in which animals were fed with ketogenic diets for only 24 or 48 h. The results showed that autophagy is upregulated in the livers of animals fed with the ketogenic diet. Moreover, the size of the observed effect was likely dependent on the diet composition. Subsequently, the markers of regulatory pathways that may link ketogenic diet action to autophagy were measured, i.e., the activity of mTORC1, activation of AMPK, and the levels of SIRT1, p53, and FOXO3. Overall, observed treatment-specific effects including the upregulation of SIRT1 and downregulation of FOXO3 and p53. Finally, a GC/MS analysis of the fatty acid composition of animals' livers and the chows was performed in order to obtain an idea about the presence of specific compounds that may shape the effects of ketogenic diets on autophagy.

Physical activity reduces anxiety and regulates brain fatty acid synthesis.

Physical activity impacts brain functions, but the direct mechanisms of this effect are not fully recognized or understood. Among multidimensional changes induced by physical activity, brain fatty acids (FA) appear to play an important role; however, the knowledge in this area is particularly scarce. Here we performed global metabolomics profiling of the hippocampus and the frontal cortex (FC) in a model of voluntary running in mice. Examined brain structures responded differentially to physical activity. Specifically, the markers of the tricarboxylic acid (TCA) cycle were downregulated in the FC, whereas glycolysis was enhanced in the hippocampus. Physical activity stimulated production of myristic, palmitic and stearic FA; i.e., the primary end products of de novo lipogenesis in the brain, which was accompanied by increased expression of hippocampal fatty acid synthase (FASN), suggesting stimulation of lipid synthesis. The changes in the brain fatty acid profile were associated with reduced anxiety level in the running mice. Overall, the study examines exercise-related metabolic changes in the brain and links them to behavioral outcomes.

Methamphetamine-associated cognitive decline is attenuated by neutralizing IL-1 signaling.

Methamphetamine (METH) abusers are prone to develop a variety of comorbidities, including cognitive disabilities, and the immunological responses have been recognized as an important component involved in the toxicity of this drug. Cytokines are among the key mediators between systemic inflammatory status and tissue responses. One of these, interleukin 1 (IL-1), has been hypothesized to be involved in cognitive functions and also appears to play a pivotal role among inflammatory molecules. In the present study, we demonstrate that exposure of mice to METH markedly increased the protein level of IL-1ß in hippocampal tissue. Additionally, METH administration induced a decline in spatial learning as determined by the Morris water maze test. We next evaluated the hypothesis that blocking IL-1ß signaling can protect against METH-induced loss of cognitive functioning. The results indicated that METH-induced impaired spatial learning abilities were attenuated by co-administration of mouse IL-1 Trap, a dimeric fusion protein that incorporates the extracellular domains of both of the IL-1 receptor components required for IL-1 signaling (IL-1 receptor type 1 and IL-1 receptor accessory protein), linked to the Fc portion of murine IgG2a. This effect was associated with a decrease in hippocampal IL-1ß level. The current study indicates for the first time that the loss of METH-related cognitive decline can be attenuated by neutralizing IL-1 signaling. Our findings suggest a potential new therapeutic pathway for treatment of altered cognitive abilities that occur in METH abusing individuals.

The effect of endurance training and testosterone supplementation on the expression of blood spinal cord barrier proteins in rats.

The present study aimed to estimate the effect of endurance training, two doses of testosterone, and the combination of these stimuli on the level of the endothelial proteins claudin, occludin, JAM-1, VE-cadherin, ZO-1, ZO-2, and P-glycoprotein in rat spinal cords. Adult male Wistar rats were trained using a motor-driven treadmill for 6 weeks (40-60 min, 5 times per week) and/or were treated for 6 weeks with two doses of testosterone (i.m.; 8 mg/kg or 80 mg/kg body weight). Spinal cords were collected 48 hours after the last training cycle and stored at -80°C. The levels of selected proteins in whole tissue lysates of the spinal cord were measured by western blot. Testosterone-treated trained rats had significantly lower claudin levels than vehicle-treated trained rats. High doses of testosterone resulted in a significant decrease in claudin-5 in untrained rats compared to the control group. Both doses of testosterone significantly reduced occludin levels compared to those in vehicle-treated untrained rats. The JAM-1 level in the spinal cords of both trained and untrained animals receiving testosterone was decreased in a dose-dependent manner. The JAM-1 level in the trained group treated with high doses of testosterone was significantly higher than that in the untrained rats treated with 80 mg/kg of testosterone. VE-cadherin levels were decreased in all groups receiving testosterone regardless of endurance training and were also diminished in the vehicle-treated group compared to the control group. Testosterone treatment did not exert a significant effect on ZO-1 protein levels. Testosterone and/or training had no significant effects on ZO-2 protein levels in the rat spinal cords. Endurance training increased P-glycoprotein levels in the rat spinal cords. The results suggest that an excessive supply of testosterone may adversely impact the expression of endothelial proteins in the central nervous system, which, in turn, may affect the blood-brain barrier function.

The modification of the ketogenic diet mitigates its stunting effects in rodents.

The high-fat and low-carbohydrate ketogenic diet (HFKD) is extensively studied within the fields of numerous diseases, including cancer and neurological disorders. Since most studies incorporate animal models, ensuring the quality of ketogenic rodent diets is important, both in the context of laboratory animal welfare as well as for the accuracy of the obtained results. In this study we implemented a modification to a commonly used ketogenic rodent chow by replacing non-resorbable cellulose with wheat bran. We assessed the effects of month-long treatment with either the unmodified or the modified HFKD on the growth and development of young male rats. Daily body weight, functional performance, and brain morphometric parameters were assessed to evaluate the influence of both applied diets on rodent development. Our results revealed that the unmodified ketogenic chow induced strong side effects that included weakness, emaciation, and brain undergrowth concomitant to growth inhibition. However, application of the ketogenic chow supplemented with wheat bran suppressed these adverse side effects, which was associated with the restoration of insulin-like growth factor 1 and a decrease in corticosterone levels. We have also shown that the advantageous results of the modified HFKD are not species- or sex-specific. Our data indicate that the proposed HFKD modification even allows for its application in young animals, without causing detrimental side effects.

The behavioral and molecular evaluation of effects of social instability stress as a model of stress-related disorders in adult female rats.

The study aimed to test the hypotheses that chronic social instability stress (CSIS) alters behavioral and physiological parameters and expression of selected genes important for stress response and social behaviors. Adult female Sprague-Dawley rats were subjected to the 4-week CSIS procedure, which involves unpredictable rotation between phases of isolation and overcrowding. Behavioral analyses (Experiment 1) were performed on the same rats before and after CSIS (n = 16) and physiological and biochemical measurements (Experiment 2) were made on further control (CON; n = 7) and stressed groups (CSIS; n = 8). Behaviors in the open field test (locomotor and exploratory activities) and elevated-plus maze (anxiety-related behaviors) indicated anxiety after CSIS. CSIS did not alter the physiological parameters measured, i.e. body weight gain, regularity of estrous cycles, and circulating concentrations of stress hormones and sex steroids. QRT-PCR analysis of mRNA expression levels was performed on amygdala, hippocampus, prefrontal cortex (PFC), and hypothalamus. The main finding is that CSIS alters the mRNA levels for the studied genes in a region-specific manner. Hence, expression of POMC (pro-opiomelanocortin), AVPR1a (arginine vasopressin receptor), and OXTR (oxytocin receptor) significantly increased in the amygdala following CSIS, while in PFC and/or hypothalamus, POMC, AVPR1a, AVPR1b, OXTR, and ERß (estrogen receptor beta) expression decreased. CSIS significantly reduced expression of CRH-R1 (corticotropin-releasing hormone receptor type 1) in the hippocampus. The directions of change in gene expression and the genes and regions affected indicate a molecular basis for the behavior changes. In conclusion, CSIS may be valuable for further analyzing the neurobiology of stress-related disorders in females.

The ketogenic diet affects the social behavior of young male rats.

The positive effects of the ketogenic diet (KD) on social behavior have been recently reported in patients and rodent models of autism spectrum disorder (ASD). Given the beneficial effects of the KD on epilepsy, mitochondrial function, carbohydrate metabolism, and inflammation, treatment based on the KD has the potential to reduce some of the ASD-associated symptoms, including abnormal social interactions. It is not known whether the KD influences sociability by reducing the pathological processes underlying ASD or through some independent mechanism. The aim of the present study was to evaluate the influence of the KD on the social behavior of rats. Four-week-old Long-Evans males were treated with the KD for 4 subsequent weeks. Afterwards, behavioral tests were performed in order to evaluate sociability, locomotor activity, working memory, and anxiety-related behaviors. Additionally we performed the social interaction test in animals that were receiving ß-hydroxybutyrate or acetone. We have observed that rats fed with the KD showed increased social exploration in three different experimental settings. We did not observe any changes in the level of social interactions in animals treated with exogenous ketone bodies. The results did not show any difference in mobility or anxiety-related behaviors or working memory between the animals fed with the KD or standard rodent chow. In conclusion, we showed that the KD affects the social behavior of wild-type young adult male rats, which was not associated with other behavioral changes.

The effects of desipramine, fluoxetine, or tianeptine on changes in bulbar BDNF levels induced by chronic social instability stress and inflammation.

BACKGROUND: Stress is a major predisposing factor in the development of psychiatric disorders and potential source of augmented inflammatory processes in the brain. Increasing body of evidence shows an important role of alterations in the olfactory bulbs (OBs) function in stress-related disorders. The aim of the present study was to investigate the impact of antidepressants on the alterations of brain-derived neurotrophic factor (BDNF) induced by lipopolysaccharide (LPS) in female rats subjected to chronic social instability stress (CSIS). METHODS: 9 weeks old female rats were subjected to CSIS and injected ip once daily with desipramine (10mg/kg), fluoxetine (5mg/kg), or tianeptine (10mg/kg) for 4 weeks. On the last day of the experiment, rats being at the estrus phase of cycle were injected ip with LPS (1mg/kg) or saline. RESULTS: The BDNF mRNA and protein levels were evaluated in the olfactory bulbs. and the BDNF protein levels were measured in plasma. A single LPS administration in the stressed rats resulted in significant decrease in the bulbar BDNF mRNA, but not in the protein level. Chronic administration of desipramine, fluoxetine, or tianeptine increased the BDNF mRNA expression and protein levels in the LPS-injected stressed rats. There was no effect of the studied antidepressants on the reduction of the plasma BDNF protein level induced by CSIS and LPS. CONCLUSIONS: These results suggest that studied antidepressants were effective in inhibiting the impact of LPS on BDNF expression in the stressed rats what may be significant for beneficial action of this drugs.

Alterations in VEGF expression induced by antidepressant drugs in female rats under chronic social stress.

Vascular endothelial growth factor (VEGF) is thought to serve a role in neurogenesis and the stress response. Although a definite link between the action of antidepressants and VEGF has not been identified, it is assumed that VEGF, as a neurotrophic factor, serves an important role in the effects of antidepressant treatment. To examine this, the present study subjected adult female rats to four weeks of social instability stress and measured the effect of antidepressant treatment on the expression of VEGF. Firstly, endocrine markers of stress and body weight were measured in parallel with behavioral tests prior to and following subjection to stress. Then, the effect of 28-day daily treatment with desipramine (DMI; 10 mg/kg), fluoxetine (5 mg/kg) or tianeptine (10 mg/kg) on the number of copies of VEGF mRNA in the amygdala, hippocampus and hypothalamus, and on serum VEGF protein levels, of rats subjected to chronic stress was determined. In addition, the weight of the adrenal glands was measured following subjection to stress. Exposure to chronic stress was found to increase the rats' sucrose preference, and diminish their tendency for general exploration and time spent in the open. The relative adrenal weights of the stressed rats were significantly increased compared with the control. Plasma concentrations of corticosterone and adrenocorticotropic hormone were not significantly augmented. In addition, the present study identified that stress elevated VEGF mRNA expression in all studied neural structures. Furthermore, the results identified that the stress-induced increase in VEGF mRNA expression in the amygdala and hypothalamus was attenuated by long-term administration of DMI. Conversely, a decrease in serum VEGF concentration was observed in stressed rats, which was not reversed by treatment with antidepressants. In conclusion, the current study suggests that under conditions of stress, VEGF serves a role in the mechanism of action of DMI, through modulating activity of the norepinephrine system.