Perinatal undernourishment provokes long-lasting alterations of clusterin and fumarate hydratase expression in the rat nucleus accumbens.

BACKGROUND: Background: Perinatal malnutrition seems to provoke important neurochemical alterations in the brain that lead to higher vulnerability to develop neuropsychiatric disorders in the adulthood. OBJECTIVES: We have examined the persistence and reversibility of the changes induced by perinatal undernourishment on the expression of fumarate hydratase in the rat nucleus accumbens, bearing in mind that this expression has been previously linked with addictive disorders. Clusterin, a multifunctional protein known to be neuroprotective and possibly related to addiction in humans, was studied in parallel. METHODS: Female Wistar rats underwent a severe restriction of food during gestation and lactation. Upon weaning, a subgroup of undernourished animals was switched to normal chow and another one continued under food restriction. Control rats and their mothers were fed on chow along the experiment. Fumarate hydratase and clusterin were quantified by western blot after five months of postnatal life in the three experimental groups. RESULTS: Food restriction along the whole experimental period provoked a marked upregulation of both clusterin and fumarate hydratase in the mitochondrial fraction of the nucleus accumbens. In the case of clusterin, this upregulation was also observed in the cytosolic fraction of the nucleus accumbens. When undernourishment was limited to gestation and lactation the two proteins appeared downregulated with respect to controls. CONCLUSION: The results are consistent with the idea that perinatal malnutrition provokes marked changes in brain neurochemistry that are not fully corrected by the rehabilitation of normal feeding and could be linked to behavioural disturbances in the adulthood, that is, increased vulnerability to addiction.

Plasma midkine levels in patients with cocaine use disorder during abstinence. / Plasma midkine levels in patients with cocaine use disorder during abstinence.

Preclinical evidence suggests that endogenous midkine could play a key modulatory role on the neurotoxic and addictive effects of different kinds of drugs of abuse, including psychostimulants. However, this hypothesis has not yet been explored in humans. As a first approach to progress in this knowledge, we have comparatively studied plasma midkine levels in 75 patients with cocaine use disorder under abstinence and 26 control subjects matched for sex, age and body mass index. Patients were further segmented into early-abstinent (up to one month of abstinence, n = 30) and late-abstinent (more than one month of abstinence, n = 45). Midkine levels were quantified in plasma samples of all the participants by enzyme-linked immunosorbent assays. Early-abstinent patients exhibited a 60% increase of midkine plasma concentration in comparison with the controls. This elevation tended to normalize upon the progression of abstinence. The results obtained demonstrate that peripheral midkine levels are closely related to cocaine use and are consistent with the idea that this cytokine could play a protective role by limiting the biological activity of psychostimulants.

Diversos estudios preclínicos han sugerido que la midkina endógena podría jugar un papel modulador clave sobre los efectos neurotóxicos y adictivos de distintas drogas, incluidos los psicoestimulantes. Esta hipótesis no ha sido aún explorada en humanos. Como primer paso en esta dirección, en el presente trabajo hemos medido los niveles plasmáticos de midkina en 75 pacientes con trastorno por uso de cocaína en abstinencia y 26 controles apareados con los anteriores por sexo, edad e índice de masa corporal. Los pacientes fueron además divididos en un grupo de abstinencia temprana (menos de un mes, n = 30) y otro de abstinencia tardía (más de un mes, n = 45). Se cuantificaron los niveles plasmáticos de midkina de todos los participantes mediante un ensayo por inmunoabsorción ligado a enzimas. Los pacientes en abstinencia temprana mostraron un incremento del 60% en su concentración plasmática de midkina con respecto a los controles que tendió a desaparecer en los pacientes con periodos de abstinencia más prolongados. Los resultados demuestran que los niveles periféricos de midkina están estrechamente relacionados con el uso de cocaína y apoyan la idea de que dicha citoquina podría jugar un papel protector limitando la actividad biológica de los psicoestimulantes.

The Neuroendocrine and Metabolic Outcomes of Bariatric Surgery Depend on Presurgical Control over Eating.

BACKGROUND: The outcomes of bariatric surgery are very irregular and mostly unpredictable. The search for variables of predictive value is encouraged to help preventing therapeutic failures. OBJECTIVE: We aimed to confirm the hypothesis that preexisting eating behaviors could predict neuroendocrine and metabolic outcomes of gastric bypass surgery in morbidly obese subjects. METHODS: Twenty-one morbidly obese patients from the Bariatric Surgery Program of our hospital were selected according to the specific inclusion and exclusion criteria for this study. The subjects filled out a validated questionnaire to quantify the "loss-of-control" (LC) dimension of food craving and provided serum samples at the onset of the study and 1 year after gastric bypass surgery. Hematological, metabolic, and hormonal variables were studied by conventional clinical tests and enzyme immunoassays and checked for correlations with LC both before and after surgery. RESULTS: Those patients that had exhibited worse eating control at the beginning of the study experienced a better metabolic response 1 year after surgery in terms of reduction of serum insulin, HOMA1-IR, HOMA2-IR, and vitamin D1; all these variables were inversely correlated with presurgical LC. Serum brain-derived neurotrophic factor (BDNF) levels showed the same tendency; in fact, BDNF significantly decreased only in those patients with worse eating control. CONCLUSIONS: Problematic eating behaviors may predict a better response of insulin resistance and a specific reduction of serum BDNF in morbidly obese patients after gastric bypass surgery.

Proteomic Identification of Biomarkers Associated with Eating Control and Bariatric Surgery Outcomes in Patients with Morbid Obesity.

BACKGROUND: The current therapeutics of morbid obesity could be significantly improved after the identification of novel biomarkers associated with the food addiction endophenotype of obesity and with bariatric surgery outcomes. METHODS: We applied differential expression proteomics and enzyme-linked immunosorbent confirmatory assays to identify (a) proteins that varied according to loss of control over eating in morbidly obese patients and (b) proteins that varied between normoweight controls and patients before and 1 year after bariatric surgery. RESULTS: Clusterin was the only protein that consistently varied according to eating control in patients. Patients showed increased levels of serum amyloid P protein, apolipoprotein A4, serotransferrin, complement factors B and C3 and haptoglobin with respect to controls; the levels of all these proteins tended to return to control values 1 year after surgery. In contrast, apolipoprotein A1 and transthyretin were initially downregulated in patients and were scarcely changed by surgery. Leucine-rich alpha-2-glycoprotein was markedly increased in patients only after surgery. CONCLUSIONS: Clusterin could be of interest as a putative biomarker for food addiction diagnosis in people with morbid obesity. In addition, postsurgical normalization of the proteins initially dysregulated in obese subjects might help monitor clinical improvements after surgery, while lasting or newly detected alterations (i.e., those affecting transthyretin and leucine-rich alpha-2-glycoprotein) could reflect partial refractoriness and/or contribute to the early prediction of clinical problems.

A high-fat diet combined with food deprivation increases food seeking and the expression of candidate biomarkers of addiction.

A mouse model has been developed to study the effect of dietary fat combined with food deprivation periods on palatable food seeking and on the expression of three potential addiction biomarkers in the nucleus accumbens: fumarate hydratase (FH), ATP synthase subunit alpha (ATP5a1) and transketolase (TKT). Forty C57BL/6 J male mice, four-week old, were fed either with a high-fat (HF) diet or standard diet along the experiment. After 3 weeks of differential feeding, animals underwent a two-week training period of two daily sessions where visual cues were paired either to palatable food (chocolate cereals) or no food at all. This training was prolonged one more week with similar, one daily sessions preceded by 12 hours of food deprivation. A behavioural test was finally conducted where mice were confined for 30 minutes either in food unpaired compartments or in compartments previously paired with cereals, but now with empty food trays. Total activity during this behavioural test and serum corticosterone levels right after it were similar in all experimental groups. Mice tested in food-paired compartments showed a marked preference for the empty food tray that gradually disappeared in standard diet-fed individuals but persisted in HF-fed mice. HF-fed mice also overexpressed FH, ATP5a1 and TKT, which positively correlated with the persistence of preference for the empty food tray. It is suggested that HF diets combined with food deprivation may enhance food seeking behaviours while upregulating FH/ATP5a1/TKT, which are further envisaged as biomarkers of addiction.

Assessing addiction vulnerability with different rat strains and place preference procedures: the role of the cocaine and amphetamine-regulated transcript.

Validated biomarkers of addiction vulnerability are unavailable despite their potential value in diagnostics and therapeutics. As cocaine and amphetamine-regulated transcript (CART) peptides can be considered candidates for such biomarkers, we have studied the acute regulation of CART gene expression in the nucleus accumbens of rats with different drug-seeking behaviors. Two subgroups of Sprague-Dawley rats with different persistences of cocaine-induced and morphine-induced place preference showed a similar regulation of CART mRNA irrespective of their behavioral differences: CART gene expression was unaffected by acute cocaine and downregulated by acute morphine to a similar extent in both subgroups. Fischer 344 and Lewis rats, known to exhibit very different drug-seeking behaviors, showed lower basal expression of CART when compared with Sprague-Dawley rats, being almost undetectable in the case of the Lewis strain. Acute morphine downregulated CART in Fischer 344 rats as it did in Sprague-Dawley rats. The results tend to show that CART mRNA regulation by acute morphine or cocaine in the nucleus accumbens does not seem predictive of addiction vulnerability. However, in the particular case of Lewis rats, the pronounced hypoactivity of the CART system could contribute to the high vulnerability of this strain to develop drug-seeking behaviors.

Clusterin levels in undernourished SH-SY5Y cells.

Food-related disorders are increasingly common in developed societies, and the psychological component of these disorders has been gaining increasing attention. Both overnourishment with high-fat diets and perinatal undernourishment in mice have been linked to a higher motivation toward food, resulting in an alteration in food intake. Clusterin (CLU), a multifaced protein, is overexpressed in the nucleus accumbens (NAc) of over-fed rats, as well as in those that suffered chronic undernutrition. Moreover, an increase of this protein was observed in the plasma of obese patients with food addiction, suggesting the implication of CLU in this eating disorder. To characterize CLU's cellular mechanisms, in vitro experiments of undernutrition were performed using dopaminergic SH-SY5Y cells. To mimic in vivo dietary conditions, cells were treated with different fetal bovine serum (FBS) concentrations, resulting in control (C group) diet (10% FBS), undernourishment (U group) diet (0.5% FBS), and undernourishment diet followed by restoration of control diet (UC group) (0.5 + 10% FBS). Undernourishment compromised cell viability and proliferation, and concomitantly increased CLU secretion as well as the cytosolic pool of the protein, while decreasing the mitochondrial level. The restoration of normal conditions tended to recover cell physiology, and the normal levels and distribution of CLU. This research study is a step forward toward the characterization of clusterin as a potential marker for food addiction and nutritional status.

Clusterin overexpression as a potential neuroprotective response to the pathological effects of high fat dieting on the brain reward system.

High-fat diets (HFDs) can lead to pathological changes in the brain underlying several behavioral disturbances (e.g., reward deficiency). To further increase our knowledge of these associations, we studied the sucrose reward and the brain expression of clusterin, a protein that is overexpressed after several kind of brain damaging conditions. C57BL/6J male mice were differentially fed on an HFD or standard chow for 41 days and underwent 11 sucrose place conditioning sessions followed by 4 extinction sessions to monitor the effects of HFD on sucrose reward by means of free choice tests. We quantified clusterin expression by immunochemistry in the nucleus accumbens, dorsal striatum and cingulate cortex. HFD tended to provoke a transient potentiation in the acquisition of sucrose-conditioned place preference, but this effect was followed by a much more consistent reduction in sucrose preference, which spontaneously disappeared after 31 days of an HFD with no need for extinction learning. The HFD mice showed higher clusterin expression in the nucleus accumbens but not in the other brain areas studied. The results confirm that HFDs strongly influence the rewarding properties of palatable foods and suggest a direct connection with neurotoxic alterations in the brain reward system tagged by clusterin overexpression.

Undernutrition induces major alterations in the lipid droplets of white and brown adipose tissues in wistar rats.

Several studies have shown a relationship between the distribution of fat mass around the organism, metabolic disorders, and an increased risk of morbidity and mortality. It has been demonstrated that in obese animals there is a big rise in the white fat deposits due to hyperplasia and hypertrophy of the adipocytes. Studies related to weight and health have been more popular regarding obesity rather than extreme caquexia or calorico-proteic deficiencies, but these states are interesting from the point of view of the preferential atrophy of certain organs that may help us in the understanding of undernourishment. Moreover, the discovery of beige adipose tissue has instigated thoughts around the roles played by the different cells in the adipose tissue as well as its adaptability in pathological states. In our study we carried out morphometric, morphological, and quantitative measurements of the adipose tissue in an animal model based on a 40-50% diet restriction in comparison to control animals. We have found a decrease in the size of white adipocytes together with a variation in the lipid droplet size of brown adipocytes in undernourished animals, what may be considered as possible transformations between the types of adipose tissues, and that could be caused by an adaptive phenomenon to the undernourished state.

Influence of biomedical education on health and eating habits of university students in Spain.

OBJECTIVE: The aim of this study was to explore the influence of an enrolled degree course on health and eating habits in a population of Spanish university students (17-26 y of age). METHODS: A cross-sectional observational study was carried out with 648 students. Volunteers were stratified into biomedical (medicine and nursing, 48%) and non-biomedical students (other fields of study, 52%). Data were collected using previously self-reported questionnaires focused on anthropometric and sociodemographic profile, lifestyle practices, body image perception, health consciousness, eating habits, physical activity, and food addiction. Mann-Whitney U tests and Pearson's χ2 tests were applied to identify associations between the two groups. RESULTS: Self-reported body mass index was higher for the non-biomedical group (22.1 ± 3.1 versus 23 ± 5 kg/m2; P < 0.05), which also reported less regularity in taking meals (91 versus 95%; P < 0.05), eating fewer colored vegetables and fruits (65 versus 77%; P < 0.001) and a higher alcohol intake (27 versus 20%; P < 0.001). In contrast, the proportion of students that showed more interest in the diet-health duality (92 versus 85%; P < 0.001) and a desire to adopt healthier habits (80 versus 78%; P < 0.05) was larger in the biomedical group. Dietary habits, obtained by means of a food frequency questionnaire, suggested that biomedical students make healthier food choices. Additionally, the group of biomedical students took more walks per week (5.8 ± 1.8 versus 5.5 ± 1.9; P < 0.05). CONCLUSIONS: Healthier lifestyle factors cluster into the biomedical group in various components of the study, except food addiction where no differences were observed. The data presented here suggest the necessity to develop health promotion strategies targeting university students.

The neurotrophic factor pleiotrophin modulates amphetamine-seeking behaviour and amphetamine-induced neurotoxic effects: evidence from pleiotrophin knockout mice.

Pleiotrophin (PTN), a neurotrophic factor with important roles in survival and differentiation of dopaminergic neurons, is up-regulated in the nucleus accumbens after amphetamine administration suggesting that PTN could modulate amphetamine-induced pharmacological or neuroadaptative effects. To test this hypothesis, we have studied the effects of amphetamine administration in PTN genetically deficient (PTN -/-) and wild type (WT, +/+) mice. In conditioning studies, we found that amphetamine induces conditioned place preference in both PTN -/- and WT (+/+) mice. When these mice were re-evaluated after a 5-day period without amphetamine administration, we found that WT (+/+) mice did not exhibit amphetamine-seeking behaviour, whereas, PTN -/- mice still showed a robust drug-seeking behaviour. In immunohystochemistry studies, we found that amphetamine (10 mg/kg, four times, every 2 hours) causes a significant increase of glial fibrillary acidic protein positive cells in the striatum of amphetamine-treated PTN -/- mice compared with WT mice 4 days after last administration of the drug, suggesting an enhanced amphetamine-induced astrocytosis in the absence of endogenous PTN. Interestingly, we found in concomitant in vitro studies that PTN (3 µM) limits amphetamine (1 mM)-induced loss of viability of PC12 cell cultures, effect that could be related to the ability of PTN to induce the phosphorylation of Akt and ERK1/2. To test this possibility, we used specific Akt and ERK1/2 inhibitors uncovering for the first time that PTN-induced protective effects against amphetamine-induced toxicity in PC12 cells are mediated by the ERK1/2 signalling pathway. The data suggest an important role of PTN to limit amphetamine-induced neurotoxic and rewarding effects.

Histamine H3 receptor gene variants associated with drug abuse in patients with cocaine use disorder.

BACKGROUND: Preclinical work revealed significant interactions between ligands of the histamine H3 receptor and different drugs of abuse. In the case of psychostimulants, the results reported are somewhat controversial and human data are still scarce, despite the fact that an inverse agonist of the H3 receptor (pitolisant) has reached the market after approval for the treatment of narcolepsy. AIMS: We have studied associations between histamine H3 receptor gene variants and cocaine use disorder to increase the knowledge of the possible involvement of histamine H3 receptor in drug abuse. METHODS: Seven single nucleotide polymorphisms of the histamine H3 receptor gene were genotyped by using a multiplexing assay in 248 samples of subjects with cocaine use disorder and 500 randomized samples of subjects representative of the Spanish population. RESULTS: The study of the epidemiological information associated to the samples revealed that subjects with cocaine use disorder broadly abused alcohol, tobacco and cannabinoids. Two single nucleotide polymorphisms (rs3787430 and rs74627870) were found significantly associated with the occurrence of addiction and one more (rs13042865) was specifically related to the severity of cocaine dependence within drug abusers. CONCLUSIONS: The associations found in this study further extend the hypothesis that histamine H3 receptor function could be relevant in drug abuse in general and cocaine addiction in particular.

Sciatic Nerve Ligation Downregulates Mitochondrial Clusterin in the Rat Prefrontal Cortex.

The concentration of the multifunctional protein clusterin is reduced in the plasma of subjects with degenerative scoliosis (DS) and carpal tunnel syndrome (CTS) but elevated in the cerebrospinal fluid of neuropathic pain patients successfully treated with spinal cord stimulation. The present work tries to increase the knowledge of pain-associated changes of plasma and brain clusterin by using an animal model of neuropathy. We studied the effects of sciatic nerve ligation on mechanical allodynia (von Frey test), anxiety (elevated plus maze test), plasma clusterin (enzyme-linked immunosorbent assay) and clusterin expression in the nucleus accumbens (NAC) and prefrontal cortex (PFC) of adult male Wistar rats (western blot). The possible modulatory role of high fat (HF) dieting was also studied, bearing in mind that obesity has been also reported to influence nociception, clusterin levels and prefrontal cortex activation. Animals with nerve ligation showed mechanical allodynia, anxiety and a marked downregulation of clusterin in the mitochondrial fraction of the prefrontal cortex. Animals fed on HF also exhibited a slight increase of the sensitivity to mechanical stimuli and anxiety; however, the diet did not potentiate the effects of nerve ligation. The results did not confirm a parallelism between neuropathy, obesity and alterations of plasma levels of clusterin, but strongly suggest that the protein could be involved in the functional reorganization of the prefrontal cortex which has been recently reported in chronic pain conditions.

Pleiotrophin inhibits hippocampal long-term potentiation: a role of pleiotrophin in learning and memory.

Pleiotrophin (PTN) is a growth factor that has been shown to be involved in hippocampal synaptic plasticity and learning. To further understand the involvement of PTN in memory processes, we performed in vitro electrophysiological studies in PTN-stimulated CA1 from rat hippocampal slices combined with the behavioural testing of PTN deficient (PTN - / - ) mice. We found that PTN inhibited hippocampal long-term potentiation (LTP) induced by high-frequency stimulation (HFS) consisted in three trains of 100 Hz separated by 20 s. To test the possibility that PTN might be involved in behavioural memory processes, we tested the learning behaviour of PTN - / - mice using the Y-maze test. We did not observe significant differences in recognition memory between PTN - / - and Wild Type (WT) mice when a 30 min-interval intertrial (ITI) was used in the Y-maze test. However, whereas WT mice showed disruption of recognition memory using a 60 min-ITI, PTN - / - mice maintained the recognition memory. The data demonstrate that PTN inhibits hippocampal LTP in vitro and might play a role in memory processes in vivo.

Targeting the pleiotrophin/receptor protein tyrosine phosphatase beta/zeta signaling pathway to limit neurotoxicity induced by drug abuse.

This review compiles the scientific basis to propose the pleiotrophin/receptor protein tyrosine phosphatase beta/zeta signaling pathway as a new therapeutic target to prevent drug of abuse-induced toxicity. In addition, potential guidelines are provided for the development of new therapeutic compounds derived from that knowledge. This approach may be relevant since efficient therapeutic strategies are currently lacking in this field, even when drug-induced neurotoxicity seems to underlie the neurodegenerative disorders diagnosed in drug addicts.

Antiproliferative and cytotoxic effects of grape pomace and grape seed extracts on colorectal cancer cell lines.

Grape pomace is the source of bioactive compounds (anthocyanins, flavonols, flavan-3-ols, and stilbenes) which exhibit antiproliferative actions on cell cultures. We have investigated the antitumoral effects of grape pomace and grape seed extracts on colon cancer cells (Caco-2, HT-29) and fibroblasts. Crude extracts prepared from white and red pomace, and grape seeds, reduced the viability and proliferation of Caco-2. HT-29 cells were resistant to these actions. Purified extracts were then prepared from the same sources and compared with the LDH test; again, all three extracts were active and purified extract from grape seed was the most potent and specific on Caco-2 cells. HT-29 cells were more sensitive to these purified extracts. The biological activity resided almost exclusively in the flavonol and flavan-3-ols subfractions, rather than the anthocyanin subfraction. Preliminary results on the mechanisms involved in these effects revealed downregulation of Myc gene expression in HT-29 and upregulation of Ptg2 in Caco-2 cells.

Pleiotrophin prevents cocaine-induced toxicity in vitro.

Pleiotrophin is a cytokine involved in differentiation, survival and repair processes in the central nervous system. Pleiotrophin is upregulated in the brain after administration of different drugs of abuse, thus suggesting a protective role of this cytokine on drug-induced toxicity. We have tested this hypothesis in vitro using NG108-15 cells, a line widely used for neurotoxicity studies. It was found that pleiotrophin (3 and 6 microM) significantly prevents cocaine (5 mM)-induced cytotoxicity as measured by the neutral red test. Similar results were obtained in PC12 cells, which were found to endogenously express both pleiotrophin and its main target, receptor protein tyrosine phosphatase (RPTP) beta/zeta. Blockade of pleiotrophin signaling using anti-pleiotrophin antibodies (2 microg/ml) did not potentiate cocaine-induced toxicity; interestingly, incubation of PC12 cells only with anti-pleiotrophin antibodies significantly reduced cellular viability, thus suggesting an important role of endogenous pleiotrophin signaling in cell survival. The data suggest that pleiotrophin overexpression in response to drugs of abuse may be relevant to prevent drug-induced toxicity.

Noradrenergic and opioidergic alterations in neuropathy in different rat strains.

The Fischer 344 (F344) rat strain differs from the Lewis strain in the response to neuropathic pain. Recently, we found that F344 rats totally recover from mechanical allodynia induced by chronic constriction injury (CCI) of the sciatic nerve 28 days after surgery whereas Lewis rats are initiating their recovery at this time point. Thus, the use of this neuropathic pain model in these different rat strains constitutes a good strategy to identify possible target genes involved in the development of neuropathic pain. Since differences between Lewis and F344 rats in their response to pain stimuli in acute pain models have been related to differences in the endogenous opioid and noradrenergic systems, we aimed to determine the levels of expression of key genes of both systems in the spinal cord and dorsal root ganglia (DRG) of both strains 28 days after CCI surgery. Real time RT-PCR revealed minimal changes in gene expression in the spinal cord after CCI despite the strain considered, but marked changes in DRG were observed. A significant upregulation of prodynorphin gene expression occurred only in injured DRG of F344 rats, the most resistant strain to neuropathic pain. In addition, we found a significant downregulation of tyrosine hydroxylase and proenkephalin gene expression levels in both strains whereas delta-opioid receptor was found to be significantly downregulated only in injured DRG of Lewis rats although the same trend was observed in F344 rats. The data strongly suggest that dynorphins could be involved in strain differences concerning CCI resistance.

Comparative study of alpha2-adrenoceptors in Fischer 344 and Lewis rats. Evidence for clonidine-induced place aversion.

Fischer 344 (F344) and Lewis rat strains have been shown to exhibit different vulnerability to development or maintenance of opioid seeking behaviours probably due to differences in the endogenous opioid system. Since opioid and alpha(2)-adrenergic mechanisms closely interact in nociception and substance abuse, strain differences may be expected to affect alpha(2)-adrenoceptor-mediated events. The sensitivity of these two strains to alpha(2)-adrenoceptor-mediated antinociception has been reported to be markedly different. In this work we have further studied the function of alpha(2)-adrenoceptors in F344 and Lewis rats by means of several in vivo and in vitro procedures. Comparative studies of [(3)H]RX821002 and [(35)S]GTPgammaS binding revealed that alpha(2)-adrenoceptors could be slightly more responsive to agonist stimulation in the brain cortex of F344 rats, which is in agreement with previous antinociception studies. However, these differences were modest, not observed in the spinal cord and did not translate into functional differences concerning the effects of clonidine on vas deferens contractility and body temperature. Conditioning experiments showed that a moderate dose of clonidine, which is relevant in antinociceptive and opioid antiwithdrawal studies, induces a robust place aversion which is also equivalent in F344 and Lewis rats. This finding underlies the consistency of the effect and its independency of genetic differences between both rat strains. It seems therefore that the pharmacological properties of alpha(2)-adrenoceptors are similar in F344 and Lewis rats, and thus the previously reported differences in clonidine-induced antinociception could be attributed to other factors such as dissimilar endogenous function of specific noradrenergic pathways.

Cocaine and amphetamine regulated transcript and brain-derived neurotrophic factor in morbid obesity. One-year follow-up after gastric bypass.

BACKGROUND: The identification of biomarkers associated with obesity and response to treatment could represent an important advance to design more effective and personalized therapeutic strategies. The complexity of morbid obesity could be explained as the combination of genetic, biochemical, cultural, and behavioral factors, among others. The study of biomarkers should be considered a determinant factor taken into account in this equation. OBJECTIVES: The aim of this study was to define better biomarker profiles potentially associated to the short-term outcome of bariatric surgery by paying attention to cocaine and amphetamine regulated transcript and brain-derived neurotrophic factor, 2 neuropeptides related to eating behavior. SETTING: University General Hospital of Ciudad Real, Spain. METHODS: Twenty-seven morbidly obese patients and 30 healthy weight individuals matched by age and sex were selected for the study. RESULTS: Patients underwent bariatric surgery by Roux-en-Y gastric bypass and responded adequately in terms of weight loss and normalization of many biochemical parameters 1 year postsurgery. A multivariate analysis showed that the hormonal/neuropeptidic profile explained 82% of the variability of the weight loss response. The evolution of cocaine and amphetamine regulated transcript paralleled that of insulin and leptin, serum levels of this peptide were initially elevated in patients (4.24 ± .47 ng/mL) with respect to controls (2.94 ± .2 ng/mL), but this difference disappeared 1 year after Roux-en-Y gastric bypass (3.14 ± .26 ng/mL). Brain-derived neurotrophic factor levels were also decreased by Roux-en-Y gastric bypass (11.93 ± .96 ng/mL postsurgery versus 15.3 ± 1.02 ng/mL presurgery), even when this peptide was not elevated in patients before surgery (14.23 ± .86 ng/mL in controls). CONCLUSIONS: The results suggest that cocaine and amphetamine regulated transcript and brain-derived neurotrophic factor could be envisaged as new candidate biomarkers of short-term outcome after surgery.