Cannabinoid-Induced Enhanced Interaction and Protein Levels of Serotonin 5-HT2A and Dopamine D2 Receptors in Rat Prefrontal Cortex

Recent evidence suggests that non-selective cannabinoid receptor agonists may regulate serotonin 2A (5-HT2A) receptor neurotransmission in brain. The molecular mechanisms of this regulation are unknown but could involve cannabinoid-induced enhanced interaction between 5-HT2A and dopamine D2 (D2) receptors. Here, we present experimental evidence that Sprague-Dawley rats treated with a non-selective cannabinoid receptor agonist (CP55,940, 50μg/kg, 7days, i.p.) showed enhanced co-immunoprecipitation of 5-HT2A and D2 receptors and enhanced membrane-associated expression of D2 and 5-HT2A receptors in prefrontal cortex (PFCx). Furthermore, 5-HT2A receptor mRNA levels were increased in PFCx suggesting a cannabinoid-induced upregulation of 5-HT2A receptors. To date, two cannabinoids receptors have been found in brain, CB1 and CB2 receptors. We used selective cannabinoid agonists in a neuronal cell line to study mechanisms that could mediate this 5-HT2A receptor upregulation. We found that selective CB2 receptor agonists upregulate 5-HT2A receptors by a mechanism that seems to involve activation of Gαi G-proteins, ERK1/2, and AP-1 transcription factor. We hypothesize that the enhanced cannabinoid-induced interaction between 5-HT2A and D2 receptors and in 5-HT2A and D2 receptors protein levels in the PFCx might provide a molecular mechanism by which activation of cannabinoid receptors might be contribute to the pathophysiology of some cognitive and mood disorders

Cannabinoid-induced upregulation of serotonin 2A receptors in the hypothalamic paraventricular nucleus and anxiety-like behaviors in rats

Recent behavioral reports suggest that repeated exposure to cannabis and synthetic cannabinoid agonists is linked with mental disorders associated with dysfunction of serotonin 2A (5-HT2A) receptor neurotransmission such as anxiety and depression. Here, we studied the effect of a nonselective cannabinoid agonist, CP55940, on the activity of 5-HT2A receptors in hypothalamic paraventricular nucleus (PVN). We detected that repeated exposure to CP55940 enhanced the prolactin and corticosterone neuroendocrine responses mediated by 5-HT2A receptors and increased the membrane-associated levels of 5-HT2A receptors in PVN. Importantly, we also detected increased anxiety-like behaviors in CP55940 treated rats compared to controls. The data presented here suggest that the mechanisms mediating the cannabinoid-induced upregulation of 5-HT2A receptors would be brain-region specific, as we were unable to detect a CP55940-induced upregulation of 5-HT2A mRNA. Our results might provide insight into the molecular mechanism by which repeated exposure to cannabinoids could be associated with the pathophysiology of neuropsychiatric disorders

Light Image Therapy in the Health Care Environment.

Use of positive distraction in the built healthcare environment to assist in alleviating stress in a patient was investigated. A backlit light image was mounted in the ceiling of an examination room to create a positive distraction for patients in the ETSU Pediatric Clinic in Johnson City, TN. Survey instruments were used to collect sample data from patients and physicians in a randomized, balanced controlled study designed to determine if patients experienced less stress in the room with the backlit image as compared to other rooms (treatments). Although a statistical difference was not determined between the room with the backlit image and positive and negative control rooms, patients in rooms containing nature art tended to exhibit less anxiety. Researched based knowledge for creating positive distractions in the built healthcare environment helps designers create environments that benefit the patients, their families and medical staff of healthcare facilities

Decreased Phosphorylation and Increased Methionine Oxidation of α-Synuclein in the Methionine Sulfoxide Reductase A Knockout Mouse

Previously, we have showed that overexpression of methionine-oxidized α-synuclein in methionine sulfoxide reductase A (MsrA) null mutant yeast cells inhibits α-synuclein phosphorylation and increases protein fibrillation. The current studies show that ablation of mouse MsrA gene caused enhanced methionine oxidation of α-synuclein while reducing its own phophorylation levels, especially in the hydrophobic cell-extracted fraction. These data provide supportive evidence that a compromised MsrA function in mammalian brain may cause enhanced pathologies associated with altered α-synuclein oxidation and phosphorylation levels

Cannabinoid 2 Receptor- and Beta Arrestin 2-Dependent Upregulation of Serotonin 2A Receptors

Recent evidence suggests that cannabinoid receptor agonists may regulate serotonin 2A (5-HT2A) receptor neurotransmission in the brain, although no molecular mechanism has been identified. Here, we present experimental evidence that sustained treatment with a non-selective cannabinoid agonist (CP 55,940) or selective CB2 receptor agonists (JWH 133 or GP 1a) upregulate 5-HT2A receptors in a neuronal cell line. Furthermore, this cannabinoid receptor agonist-induced upregulation of 5-HT2A receptors was prevented in cells stably transfected with either CB2 or β-Arrestin 2 shRNA lentiviral particles. Additionally, inhibition of clathrin-mediated endocytosis also prevented the cannabinoid receptor-induced upregulation of 5-HT2A receptors. Our results indicate that cannabinoid agonists might upregulate 5-HT2A receptors by a mechanism that requires CB2 receptors and β-Arrestin 2 in cells that express both CB2 and 5-HT2A receptors. 5-HT2A receptors have been associated with several physiological functions and neuropsychiatric disorders such as stress response, anxiety & depression and schizophrenia. Therefore, these results might provide a molecular mechanism by which activation of cannabinoid receptors might be relevant to some cognitive and mood disorders in humans

Cannabinoid Agonists Increase the Interaction between β-Arrestin 2 and ERK1/2 and Upregulate β-Arrestin 2 and 5-HT2A Receptors

We have recently reported that selective cannabinoid 2 (CB2) receptor agonists upregulate 5-HT2A receptors by enhancing ERK1/2 signaling in prefrontal cortex (PFCx). Increased activity of cortical 5-HT2A receptors has been associated with several neuropsychiatric disorders such as anxiety and schizophrenia. Here we examine the mechanisms involved in this enhanced ERK1/2 activation in rat PFCx and in a neuronal cell model. Sprague-Dawley rats treated with a non-selective cannabinoid agonist (CP55940, 50 μg/kg, 7 days, i.p.) showed enhanced co-immunoprecipitation of β-Arrestin 2 and ERK1/2, enhanced pERK protein levels, and enhanced expression of β-Arrestin 2 mRNA and protein levels in PFCx. In a neuronal cell line, we found that selective CB2 receptor agonists upregulate β-Arrestin 2, an effect that was prevented by selective CB2 receptor antagonist JTE-907 and CB2 shRNA lentiviral particles. Additionally, inhibition of clathrin-mediated endocytosis, ERK1/2, and the AP-1 transcription factor also prevented the cannabinoid receptor-induced upregulation of β-Arrestin 2. Our results suggest that sustained activation of CB2 receptors would enhance β-Arrestin 2 expression possibly contributing to its increased interaction with ERK1/2 thereby driving the upregulation of 5-HT2A receptors. The CB2 receptor-mediated upregulation of β-Arrestin 2 would be mediated, at least in part, by an ERK1/2-dependent activation of AP-1. These data could provide the rationale for some of the adverse effects associated with repeated cannabinoid exposure and shed light on some CB2 receptor agonists that could represent an alternative therapeutic because of their minimal effect on serotonergic neurotransmission

Activation of the JAK-STAT pathway by olanzapine is necessary for desensitization of serotonin2A receptor-stimulated phospholipase C signaling in rat frontal cortex but not serotonin2A receptor-stimulated hormone release

Chronic treatment with olanzapine causes desensitization of serotonin2A receptor signaling. The purpose of the current study is to further understand the mechanisms underlying this desensitization response of serotonin2A receptor signaling in vivo. We now report that desensitization of serotonin2A receptor stimulated-phospholipase C activity in rat frontal cortex induced by olanzapine is dependent on activation of the JAK-STAT pathway. Olanzapine treatment for 7 days significantly increased the levels of the regulator of G protein signaling (RGS7) protein, RGS7 mRNA levels, and activation of JAK2 in rat frontal cortex. Pretreatment with a JAK2 inhibitor AG490, significantly attenuated the olanzapine-induced reductions in serotonin2A receptor-stimulated phospholipase C activity and prevented the olanzapine-induced increases in RGS7 mRNA and protein levels. In contrast, inhibition of the JAK-STAT pathway with AG490 did not reverse the olanzapine-induced desensitization of the serotonin2A receptor pathway in the hypothalamic paraventricular nucleus mediating increases in plasma hormone levels. AG490 dose-dependently inhibited serotonin2A receptor-stimulated oxytocin and corticosterone release. Taken together, these results suggest that the olanzapine-induced increase in RGS7 expression is mediated by activation of JAK-STAT and is necessary for olanzapine-induced desensitization of serotonin2A receptor-stimulated phospholipase C activity in the frontal cortex but not serotonin2A receptor-stimulated hormone release

Estradiol induces partial desensitization of serotonin 1A receptor signaling in the paraventricular nucleus of the hypothalamus and alters expression and interaction of RGSZ1and Gαz

Hyperactivity of hypothalamic-pituitary mediated hormone responses, such as to stimulation with a serotonin 1A (5-HT1A) receptor agonist, are a feature of depression which are normalized with clinical improvement during drug therapy. We previously reported that SSRIs induce desensitization of 5-HT1A receptor signaling in the paraventricular nucleus of the hypothalamus (PVN) while estradiol benzoate (EB) produces a more rapid, partial desensitization. In the current study, time-course and dose-response experiments demonstrated that two once daily doses of EB is the minimum needed to induce the desensitization response as indicated by 5-HT1A receptor-stimulated release of oxytocin and that 10 μg/kg/day EB produces the maximal response, a partial desensitization of approximately 40%. The effects of two once daily injections of 10 μg/kg/day EB on Gαz and RGSZ1 proteins were examined as components of the 5-HT1A receptor signaling system, which mediates the release of oxytocin and adrenocorticotropin hormone. RGSZ1 appears to be a major target for EB-mediated responses in the 5-HT1A receptor signaling system. A 55 kD membrane-associate RGSZ1 protein was greatly increased in the PVN and rest of the hypothalamus and moderately increased in the dorsal hippocampus and amygdala after EB treatment as well as after an acute dose of a 5-HT1A receptor agonist. These results suggest that EB is a candidate for adjuvant therapy with SSRIs to hasten the therapeutic response and that RGSZ1 is a major target of EB therapy which could be explored as a target for novel therapeutic approaches for the treatment of depression

Clasificación secuencial tecno-tipológica de las fíbulas de codo de la Península Ibérica.

Sin resume

Eficacia de la solución de dextrosa al 5% con cloruro de sodio al 20% y bicarbonato de sodio en la reanimación hidroelectrolítica de niños quemados de 0 a 14 años en las primeras 24 horas de atención

Objetivo: Determinar la Eficacia de la Solución de Dextrosa al 5% con Cloruro de Sodio al 20% y Bicarbonato de Sodio (Solución D), en comparación con la Solución de la Fórmula de Parkland (Solución P), en la reanimación hidroelectrolítica de niños quemados en las primeras 24 horas. Materiales v Métodos: Experimental, Ensayo clínico controlado doble ciego. Muestra: Pacientes menores de 14 años, con quemaduras por fuego o líquidos con > 10% de SCQ, que lleguen en las 24 primeras horas luego de la quemadura. Se dividieron 2 grupos al azar: Grupo A: Solución P (n=15); Grupo B: Solución D (n=14). Al ingreso y a las 24h se tomaron muestras sanguíneas para analizarlas. El volumen requerido se calculó de acuerdo al %SCQ; en ambos grupos, 50% del volumen total se administró en las primeras 8 horas, 50% restante en las siguientes 16 horas. Resultados: Ambos grupos presentaron distribución similar en edad, género, peso y %SCQ. Al ingreso, 4 pacientes presentaron Taquisfigmia, 5 Taquipnea, 26 Hiponatremia, 23 Hiperkalemia, 23 Acidosis Metabólica. En el control a las 24h, 1 paciente presentó Hipematremia, 1 Hipercalemia y 2 Acidosis Metabólica (Grupo A); FC y FR se regularon a valores normales, no se encontró diferencias significativas respecto a Glucosa y Hematocrito, 100% tuvo Diuresis> lml/kg/h y BH (+),a pesar de esto, ninguno presentó edemas, no hubo alteración de Urea y Creatinina Mortalidad 0%. Conclusión: La Solución D tiene la misma eficacia que la Solución P en la reanimación hidroelectrolítica del shock por quemadura en niños