Short-Term Modulation of Extracellular Signal-Regulated Kinase 1/2 and Stress-Activated Protein Kinase/c-Jun NH2-Terminal Kinase in Pancreatic Islets by Glucose and Palmitate Possible Involvement of Ceramide

Objectives: The effect of glucose and palmitate on the phosphorylation of proteins associated with cell growth and survival (extracellular signal-regulated kinase 1/2 [ERK1/2] and stress-activated protein kinase/c-Jun NH2-terminal kinase [SAPK/JNK]) and on the expression of immediate early genes was investigated. Methods: Groups of freshly isolated rat pancreatic islets were incubated in 10-mmol/L glucose with palmitate, LY294002, or fumonisin B1 for the measurement of the phosphorylation and the content of ERK1/2, JNK/SAPK, and v-akt murine thymoma viral oncongene (AKT) (serine 473) by immunoblotting. The expressions of the immediate early genes, c-fos and c-jun, were evaluated by reverse transcription-polymerase chain reaction. Results: Glucose at 10 mmol/L induced ERK1/2 and AKT phosphorylations and decreased SAPK/JNK phosphorylation. Palmitate (0.1 mmol/L) abolished the glucose effect on ERK1/2, AKT, and SAPK/JNK phosphorylations. LY294002 caused a similar effect. The inhibitory effect of palmitate on glucose-induced ERK1/2 and AKT phosphorylation changes was not observed in the presence of fumonisin B1. Glucose increased c-fos and decreased c-jun expressions. Palmitate and LY294002 abolished these latter glucose effects. The presence of fumonisin B1 abolished the effect induced by palmitate on c-jun expression. Conclusions: Our results suggest that short-term changes of mitogen-activated protein kinase and AKT signaling pathways and c-fos and c-jun expressions caused by glucose are abolished by palmitate through phosphatidylinositol 3-kinase inhibition via ceramide synthesis.

Dissecting the brain`s fear system reveals the hypothalamus is critical for responding in subordinate conspecific intruders

Effective defense against natural threats in the environment is essential for the survival of individual animals. Thus, instinctive behavioral responses accompanied by fear have evolved to protect individuals from predators and from opponents of the same species (dominant conspecifics). While it has been suggested that all perceived environmental threats trigger the same set of innately determined defensive responses, we tested the alternate hypothesis that different stimuli may evoke differentiable behaviors supported by distinct neural circuitry. The results of behavioral, neuronal immediate early gene activation, lesion, and neuroanatomical experiments indicate that the hypothalamus is necessary for full expression of defensive behavioral responses in a subordinate conspecific, that lesions of the dorsal premammillary nucleus drastically reduce behavioral measures of fear in these animals, and that essentially separate hypothalamic circuitry supports defensive responses to a predator or a dominant conspecific. It is now clear that differentiable neural circuitry underlies defensive responses to fear conditioning associated with painful stimuli, predators, and dominant conspecifics and that the hypothalamus is an essential component of the circuitry for the latter two stimuli.

Transdural motor cortex stimulation reverses neuropathic pain in rats: A profile of neuronal activation

Motor cortex stimulation (MCS) has been used to treat patients with neuropathic pain resistant to other therapeutic approaches; however, the mechanisms of pain control by MCS are still not clearly understood. We have demonstrated that MCS increases the nociceptive threshold of naive conscious rats, with opioid participation. In the present study, the effect of transdural MCS on neuropathic pain in rats subjected to chronic constriction injury of the sciatic nerve was investigated. In addition, the pattern of neuronal activation, evaluated by Fos and Zif268 immunolabel, was performed in the spinal cord and brain sites associated with the modulation of persistent pain. MCS reversed the mechanical hyperalgesia and allodynia induced by peripheral neuropathy. After stimulation, Fos immunoreactivity (Fos-IR) decreased in the dorsal horn of the spinal cord and in the ventral posterior lateral and medial nuclei of the thalamus, when compared to animals with neuropathic pain. Furthermore, the MCS increased the Fos-IR in the periaqueductal gray, the anterior cingulate cortex and the central and basolateral amygdaloid nuclei. Zif268 results were similar to those obtained for Fos, although no changes were observed for Zif268 in the anterior cingulate cortex and the central amygdaloid nucleus after MCS. The present findings suggest that MCS reverts neuropathic pain phenomena in rats, mimicking the effect observed in humans, through activation of the limbic and descending pain inhibitory systems. Further investigation of the mechanisms involved in this effect may contribute to the improvement of the clinical treatment of persistent pain. (c) 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.

THE ROLE OF THE SUPERIOR COLLICULUS IN PREDATORY HUNTING

Combining the results of behavioral, neuronal immediate early gene activation, lesion and neuroanatomical experiments, we have presently investigated the role of the superior colliculus (SC) in predatory hunting. First, we have shown that insect hunting is associated with a characteristic large increase in Fos expression in the lateral part of the intermediate gray layer of the SC (Wig). Next, we have shown that animals with bilateral NMDA lesions of the lateral parts of the SC presented a significant delay in starting to chase the prey and longer periods engaged in other activities than predatory hunting. They also showed a clear deficit to orient themselves toward the moving prey and lost the stereotyped sequence of actions seen for capturing, holding and killing the prey. Our Phaseolus vulgaris-leucoagglutinin analysis revealed that the lateral SCig, besides providing the well-documented descending crossed pathway to premotor sites in brainstem and spinal cord, projects to a number of midbrain and diencephalic sites likely to influence key functions in the context of the predatory behavior, such as general levels of arousal, motivational level to hunt or forage, behavioral planning, appropriate selection of the basal ganglia motor plan to hunt, and motor output of the primary motor cortex. In contrast to the lateral SC lesions, medial SC lesions produced a small deficit in predatory hunting, and compared to what we have seen for the lateral SCig, the medial SCig has a very limited set of projections to thalamic sites related to the control of motor planning or motor output, and provides conspicuous inputs to brainstem sites involved in organizing a wide range of anti-predatory defensive responses. Overall, the present results served to clarify how the different functional domains in the SC may mediate the decision to pursue and hunt a prey or escape from a predator. (C) 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Environmental modulation of ethanol-induced locomotor activity: Correlation with neuronal activity in distinct brain regions of adolescent and adult Swiss mice

Drug abuse is a concerning health problem in adults and has been recognized as a major problem in adolescents. induction of immediate-early genes (IEG), such as c-Fos or Egr-1, is used to identify brain areas that become activated in response to various stimuli, including addictive drugs. It is known that the environment can alter the response to drugs of abuse. Accordingly, environmental cues may trigger drug-seeking behavior when the drug is repeatedly administered in a given environment. The goal of this study was first to examine for age differences in context-dependent sensitization and then evaluate IEG expression in different brain regions. For this, groups of mice received i.p. ethanol (2.0 g/kg) or saline in the test apparatus, while other groups received the solutions in the home cage, for 15 days. One week after this treatment phase, mice were challenged with ethanol injection. Acutely, ethanol increased both locomotor activity and IEG expression in different brain regions, indistinctly, in adolescent and adult mice. However, adults exhibited a typical context-dependent behavioral sensitization following repeated ethanol treatment, while adolescent mice presented gradually smaller locomotion across treatment, when ethanol was administered in a paired regimen with environment. Conversely, ethanol-treated adolescents expressed context-independent behavioral sensitization. Overall, repeated ethanol administration desensitized IEG expression in both adolescent and adult mice, but this effect was greatest in the nucleus accumbens and prefrontal cortex of adolescents treated in the context-dependent paradigm. These results suggest developmental differences in the sensitivity to the conditioned and unconditioned locomotor effects of ethanol. (C) 2008 Elsevier B.V. All rights reserved.

Development of an adenoviral vector with robust expression driven by p53

Here we introduce a new adenoviral vector where transgene expression is driven by p53. We first developed a synthetic promoter, referred to as PGTx beta containing a p53-responsive element, a minimal promoter and the first intron of the rabbit P-globin gene. Initial assays using plasmid-based vectors indicated that expression was tightly controlled by p53 and was 5-fold stronger than the constitutive CMV immediate early promoter/enhancer. The adenoviral vector, AdPG, was also shown to offer p53-responsive expression in prostate carcinoma cells LNCaP (wt p53), DU-145 (temperature sensitive mutant of p53) and PC3 (p53-null, but engineered to express temperature-sensitive p53 mutants). AdPG served as a sensor of p53 activity in LNCaP cells treated with chemotherapeutic agents. Since p53 can be induced by radiotherapy and chemotherapy, this new vector could be further developed for use in combination with conventional therapies to bring about cooperation between the genetic and pharmacologic treatment modalities. (c) 2007 Elsevier Inc. All rights reserved.

Immediate reconstruction following breast-conserving surgery: Management of the positive surgical margins and influence on secondary reconstruction

The efficacy of breast-conserving Surgery for the local control of early breast cancer has been repeatedly evidenced. Although immediate reconstruction following breast-conserving Surgery has been described, little information is available regarding surgical management in reoperative settings due to positive margins. We studied the influence of intraoperatively assessed and postoperatively controlled Surgical margin status on the type of breast-conserving Surgery and report our results regarding complications in a reoperative breast reconstruction scenario. All patients were seen by a multidisciplinary team who recommended breast-conserving surgery. According to the breast volume, ptosis and tumor size/location, the patients were also evaluated by a plastic Surgeon, who recommended reconstruction with the appropriate technique. Intraoperative assessment Of Surgical margins was determined by histological examination of frozen sections. The mean follow-up time was 48 months. Two hundred and eighteen patients (88.5%) underwent breast-conserving Surgery and immediate reconstruction. Twelve (5.5%) patients had a positive tumor margin after review of the permanent section. All patients underwent re-exploration. In 1.3%, a second reconstructive technique was indicated and in 2.2% a skin-sparing mastectomy with total reconstruction was performed. Our findings support the important role of the intraoperative assessment of surgical margins and its interference in the selection of reconstruction techniques and negative margins: however, it will not guarantee complete excision of the tumor. Success depends on coordinated planning with the oncologic Surgeon and careful intraoperative management, (C) 2008 Elsevier Ltd. All rights reserved.