Serum Level of miR-1 and miR-155 as Potential Biomarkers of Stress-Resilience of NET-KO and SWR/J Mice.

In the present study, we used three strains of mice with various susceptibility to stress: mice with knock-out of the gene encoding norepinephrine transporter (NET-KO), which are well characterized as displaying a stress-resistant phenotype, as well as two strains of mice displaying two different stress-coping strategies, i.e., C57BL/6J (WT in the present study) and SWR/J. The procedure of restraint stress (RS, 4 h) was applied, and the following behavioral experiments (the forced swim test and sucrose preference test) indicated that NET-KO and SWR/J mice were less sensitive to RS than WT mice. Then, we aimed to find the miRNAs which changed in similar ways in the serum of NET-KO and SWR/J mice subjected to RS, being at the same time different from the miRNAs found in the serum of WT mice. Using Custom TaqMan Array MicroRNA Cards, with primers for majority of miRNAs expressed in the serum (based on a preliminary experiment using the TaqMan Array Rodent MicroRNA A + B Cards Set v3.0, Thermo Fisher Scientific, Waltham, MA, USA) allowed the identification of 21 such miRNAs. Our further analysis focused on miR-1 and miR-155 and their targets-these two miRNAs are involved in the regulation of BDNF expression and can be regarded as biomarkers of stress-resilience.

Cardiovascular stability and unchanged muscle sympathetic activity during xenon anaesthesia: role of norepinephrine uptake inhibition.

BACKGROUND: Intraoperative hypotension is associated with increased risk of perioperative complications. The N-methyl-d-aspartate (NMDA) receptor (NMDA-R) antagonist xenon (Xe) induces general anaesthesia without impairment of cardiac output and vascular resistance. Mechanisms involved in cardiovascular stability have not been identified. METHODS: Muscle sympathetic activity (MSA) (microneurography), sympathetic baroreflex gain, norepinephrine (NE) plasma concentration (high-performance liquid chromatography), anaesthetic depth (Narcotrend(®) EEG monitoring), and vital parameters were analysed in vivo during Xe mono-anaesthesia in human volunteers (n=8). In vitro, NE transporter (NET) expressing HEK293 cells and SH-SY5Y neuroblastoma cells were pre-treated with ketamine, MK-801, NMDA/glycine, or vehicle. Subsequently, cells were incubated with or without Xe (65%). NE uptake was measured by using a fluorescent NET substrate (n=4) or [(3)H]NE (n=6). RESULTS: In vivo, Xe anaesthesia increased mean (standard deviation) arterial pressure from 93 (4) to 107 (6) mm Hg and NE plasma concentration from 156 (55) to 292 (106) pg ml(-1), P<0.01. MSA and baroreflex gain were unaltered. In vitro, ketamine decreased NET activity (P<0.01) in NET-expressing HEK293 cells, while Xe, MK-801, and NMDA/glycine did not. Xe reduced uptake in SH-SY5Y cells expressing NET and NMDA-Rs (P<0.01). MK-801 (P<0.01) and ketamine (P<0.01) also reduced NET activity, but NMDA/glycine blocked the effect of Xe on [(3)H]NE uptake. CONCLUSIONS: In vivo, Xe anaesthesia does not alter sympathetic activity and baroreflex gain, despite increased mean arterial pressure. In vitro, Xe decreases the uptake of NE in neuronal cells by the inhibition of NET. This inhibition might be related to NMDA-R antagonism and explain increased NE concentrations at the synaptic cleft and in plasma, contributing to cardiovascular stability during Xe anaesthesia.

Estimates of serotonin and norepinephrine transporter inhibition in depressed patients treated with paroxetine or venlafaxine.

Paroxetine and venlafaxine are potent serotonin transporter (SERT) antagonists and weaker norepinephrine transporter (NET) antagonists. However, the relative magnitude of effect at each of these sites during treatment is unknown. Using a novel blood assay that estimates CNS transporter occupancy we estimated the relative SERT and NET occupancy of paroxetine and venlafaxine in human subjects to assess the relative magnitude of SERT and NET inhibition. Outpatient subjects (N=86) meeting criteria for major depression were enrolled in a multicenter, 8 week, randomized, double-blind, parallel group, antidepressant treatment study. Subjects were treated by forced-titration of paroxetine CR (12.5-75 mg/day) or venlafaxine XR (75-375 mg/day) over 8 weeks. Blood samples were collected weekly to estimate transporter inhibition. Both medications produced dose-dependent inhibition of the SERT and NET. Maximal SERT inhibition at week 8 for paroxetine and venlafaxine was 90% (SD 7) and 85% (SD 10), respectively. Maximal NET inhibition for paroxetine and venlafaxine at week 8 was 36% (SD 19) and 60% (SD 13), respectively. The adjusted mean change from baseline (mean 28.6) at week 8 LOCF in MADRS total score was -16.7 (SE 8.59) and -17.3 (SE 8.99) for the paroxetine and venlafaxine-treated patients, respectively. The magnitudes of the antidepressant effects were not significantly different from each other (95%CI -3.42, 4.54, p=0.784). The results clearly demonstrate that paroxetine and venlafaxine are potent SERT antagonists and less potent NET antagonists in vivo. NET antagonism has been posited to contribute to the antidepressant effects of these compounds. The clinical significance of the magnitude of NET antagonism by both medications remains unclear at present.

Treatment with risperidone for 4 weeks increased plasma 3-methoxy-4-hydroxypnenylglycol (MHPG) levels, but did not alter plasma brain-derived neurotrophic factor (BDNF) levels in schizophrenic patients.

In the present study, we investigated the effects of risperidone treatment for 4 weeks on plasma levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) and brain-derived neurotrophic factor (BDNF) in 89 schizophrenic patients. We also compared the plasma levels of BDNF and MHPG between the schizophrenic group and 103 sex-and age-matched normal controls. In addition, we investigated the effects of two SNPs of the noradrenaline transporter (NAT) gene on plasma levels of MHPG, BDNF, and clinical improvement. The mean dose of risperidone was 3.8+/-1.4 mg/day. We demonstrated that treatment with risperidone increased plasma MHPG levels, and this increase was associated with an improvement of the negative symptoms of schizophrenia. In contrast, plasma BDNF did not change after 4 weeks of risperidone treatment, and the two SNPs in NAT did not influence the response to risperidone treatment or plasma MHPG and BDNF levels. These results suggest that the enhancement of noradrenergic neurons by risperidone, which occurs independently of the two SNPs of NAT, plays a role in the clinical efficacy of the drug.

Noradrenaline transporter and its turnover rate are decreased in blood lymphocytes of patients with major depression.

Lymphocytes possess transporters of serotonin and dopamine, and also contain monoamines. The objective of this work was to determine the presence of noradrenaline transporters, the turnover rate of noradrenaline and serotonin in lymphocytes of major depression patients, and to correlate the biochemical parameters with the severity of the disorder. Lymphocytes from peripheral blood were isolated by Ficoll/Hypaque, and noradrenaline transporter was studied by binding of [3H]nisoxetine: control group (29, age 31.52+/-1.08, 7 men) and major depression patients (35, age 36.68+/-1.69, 6 men), Hospital Vargas de Caracas. Diagnostic was done by criteria of the American Psychiatric Association and severity by Hamilton Scale for Depression. Levels of noradrenaline, serotonin, 3-methoxy-4-hydroxyphenylglycol and 5-hydroxyindoleacetic acid were determined by HPLC. Turnover rate was evaluated by the ratios of monoamines and metabolites. Correlations were done between the biochemical parameters and the severity of depression. The score of Hamilton for Depression was 22.77+/-0.51. There was a reduction in the number of transporters in lymphocytes of patients, 0.95+/-0.27 versus 4.06+/-1.67 fmol/10(6) cells. Levels of monoamines and metabolites did not significantly differ between patients and controls. However, there was a higher monoamine/metabolite ratio in lymphocytes of patients, indicating a reduction of metabolic turnover rate. Also there was a relative greater concentration of noradrenaline than serotonin in the lymphocytes of the patients, as indicated by the ratio noradrenaline/serotonin. Noradrenergic and serotonergic turnover is decreased in blood peripheral lymphocytes of major depression patients; the reduction in noradrenaline transporter could be related to changes in intracellular levels, and these modifications could result in functional changes of the immune system.