Sensitive and simultaneous quantification of 16 neurotransmitters and metabolites in murine microdialysate by fast liquid chromatography-tandem mass spectrometry.

The sensitive and simultaneous measurement of multiple neurotransmitters in microdialysate (MD) of freely moving mice is a prerequisite to study neurochemical imbalances in specific brain regions. The quantitative analysis of 16 neurotransmitters and metabolites, including serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), melatonin (ME), dopamine (DA), levodopa (l-DOPA), 3-methoxytyramine (3-MT), norepinephrine (NE), epinephrine (EP), homovanillinic acid (HVA), acetylcholine (ACh), deoxy carnitine (iso-ACh), choline (Ch), and É£-aminobutyric acid (GABA), adenosine (ADE), glutamine (Gln), and glutamic acid (Glu) was achieved within a chromatographic separation time of 6.5 min by the application of a biphenyl column coupled to an API-QTrap 5500 (AB SCIEX) mass spectrometer. Optimized chromatographic separation as well as high sensitivity allow the simultaneous analysis and precise quantification of 16 neurotransmitters and metabolites in artificial cerebrospinal fluid (CSF). Sample preparation procedure consisted of simply adding isotopically labeled internal standard solution to the microdialysis sample. The limits of detection in aCSF ranged from 0.025 pg (Ch) to 9.75 pg (Gln) and 85.5 pg (HVA) on column. Recoveries were between 83 and 111% for neurotransmitter concentrations from 0.6 to 45 ng/ml or 200 ng/ml with a mean intra-day and inter-day coefficient of variation of 7.6% and 11.2%, respectively. Basal extracellular concentrations of the following analytes: 5-HT, 5-HIAA, ME, DA, 3-MT, HVA, ACh, iso-ACh, Ch, GABA, ADE, Gln, and Glu were determined in the striatum of mice with a MD flow rate of 0.5 µl/min. This LC-MS/MS method leads to an accurate quantification of ACh and its isobaric structure iso-ACh, which were detected in the MD samples at ratios of 1:8.6. The main advantage of the high sensitivity is the miniaturization of the MD protocol with short sample collection times and volumes down to 5 µl, which makes this method suitable for pharmacological intervention and optogenetic studies to detect neurochemical changes in vivo.

Optogenetic augmentation of the hypercholinergic endophenotype in DYT1 knock-in mice induced erratic hyperactive movements but not dystonia.

BACKGROUND: The most prevalent inherited form of generalized dystonia is caused by a mutation in torsinA (DYT1, ∆GAG) with incomplete penetrance. Rodent models with mutated torsinA do not develop dystonic symptoms, but previous ex vivo studies indicated abnormal excitation of cholinergic interneurons (ChI) and increased striatal acetylcholine. METHODS: We used in vivo optogenetics to exacerbate this endophenotype in order to determine its capacity to trigger dystonic symptoms in freely behaving mice. Tor1a+/Δgag DYT1 mice and wildtype littermates expressing channelrhodopsin2 under the Chat promotor were implanted bilaterally with optical LED cannulae and stimulated with blue light pulses of varied durations. FINDINGS: Six months old DYT1 KI mice but not wildtype controls responded with hyperactivity to blue light specifically at 25 ms pulse duration, 10 Hz frequency. Neuronal activity (c-Fos) in cholinergic interneurons was increased immediately after light stimulation and persisted only in DYT1 KI over 15 min. Substance P was increased specifically in striosome compartments in naïve DYT1 KI mice compared to wildtype. Under optogenetic stimulation substance P increased in wildtype to match levels in Dyt1 KI, and acetylcholinesterase was elevated in the striatum of stimulated DYT1 KI. No signs of dystonic movements were observed under stimulation of up to one hour in both genotypes and age groups, and the sensorimotor deficit previously observed in 6 months old DYT1 KI mice persisted under stimulation. INTERPRETATION: Overall this supports an endophenotype of dysregulated cholinergic activity in DYT1 dystonia, but depolarizing cholinergic interneurons was not sufficient to induce overt dystonia in DYT1 KI mice.

Neuroanatomy of pain-deficiency and cross-modal activation in calcium channel subunit (CACN) α2δ3 knockout mice.

The phenotype of calcium channel subunit (CACN) α2δ3 knockout (KO) mice includes sensory cross-activation and deficient pain perception. Sensory cross-activation defines the activation of a sensory cortical region by input from another modality due to reorganization in the brain such as after sensory loss. To obtain mechanistic insight into both phenomena, we employed a comprehensive battery of neuroanatomical techniques. While CACNα2δ3 was ubiquitously expressed in wild-type mice, it was absent in α2δ3 KO animals. Immunostaining of α1A, α1B, and α1E revealed upregulation of N-type and R-type, but not P/Q-type Cav2 channels in cortical neurons of CACNα2δ3 KO mice. Compared to wild-type mice, axonal processes in somatosensory cortex were enhanced, and dendritic processes reduced, in CACNα2δ3 KO mice. Immunohistochemical and MRI analyses, investigating morphology, thalamocortical and intra-/intercortical trajectories, revealed a disparity between projection and commissural fibers with reduction of the number of spatial specificity of thalamocortical projections. L1cam staining revealed wide-ranging projections of thalamocortical fibers reaching both somatosensory/motor and visual cortical areas. Activation (c-fos+) of excitatory and inhibitory neurons suggested that deficient pain perception in α2δ3 KO mice is unlikely to result from cortical disinhibition. Collectively, our data demonstrate that knock out of CACN α2δ3 results in some structural abnormalities whose functional implications converge to dedifferentiation of sensory activation.

Towards optimized anesthesia protocols for stereotactic surgery in rats: Analgesic, stress and general health effects of injectable anesthetics. A comparison of a recommended complete reversal anesthesia with traditional chloral hydrate monoanesthesia.

Although injectable anesthetics are still widely used in laboratory rodents, scientific data concerning pain and distress during and after stereotactic surgery are rare. However, optimal anesthesia protocols have a high impact on the quality of the derived data. We therefore investigated the suitability of recommended injectable anesthesia with a traditionally used monoanesthesia for stereotactic surgery in view of optimization and refinement in rats. The influence of the recommended complete reversal anesthesia (MMF; 0.15mg/kg medetomidine, 2mg/kg midazolam, 0.005mg/kg fentanyl; i.m.) with or without reversal and of chloral hydrate (430mg/kg, 3.6%, i.p.) on various physiological, biochemical and behavioral parameters (before, during, after surgery) was analyzed. Isoflurane was also included in stress parameter analysis. In all groups, depth of anesthesia was sufficient for stereotactic surgery with no animal losses. MMF caused transient exophthalmos, myositis at the injection site and increased early postoperative pain scores. Reversal induced agitation, restlessness and hypothermia. Even the low concentrated chloral hydrate led to peritonitis and multifocal liver necrosis, corresponding to increased stress hormone levels and loss in body weight. Increased stress response was also exerted by isoflurane anesthesia. Pronounced systemic toxicity of chloral hydrate strongly questions its further use in rodent anesthesia. In view of undesired effects of MMF and isoflurane, thorough consideration of anesthesia protocols for particular research projects is indispensable. Reversal should be restricted to emergency situations. Our data support further refinement of the current protocols and the importance of sham operated controls.

High frequency stimulation of the entopeduncular nucleus sets the cortico-basal ganglia network to a new functional state in the dystonic hamster.

High frequency stimulation (HFS) of the internal pallidum is effective for the treatment of dystonia. Only few studies have investigated the effects of stimulation on the activity of the cortex-basal ganglia network. We here assess within this network the effect of entopeduncular nucleus (EP) HFS on the expression of c-Fos and cytochrome oxidase subunit I (COI) in the dt(sz)-hamster, a well-characterized model of paroxysmal dystonia. In dt(sz)-hamsters, we identified abnormal activity in motor cortex, basal ganglia and thalamus. These structures have already been linked to the pathophysiology of human dystonia. EP-HFS (i) increased striatal c-Fos expression in controls and dystonic hamsters and (ii) reduced thalamic c-Fos expression in dt(sz)-hamsters. EP-HFS had no effect on COI expression. The present results suggest that EP-HFS induces a new network activity state which may improve information processing and finally reduces the severity of dystonic attacks in dt(sz)-hamsters.

Long-term effects of a shared decision-making intervention on physician-patient interaction and outcome in fibromyalgia. A qualitative and quantitative 1 year follow-up of a randomized controlled trial.

OBJECTIVE: Fibromyalgia syndrome (FMS) patients and their doctors frequently complain on interaction difficulties. We investigated the effects of a shared decision-making (SDM) intervention on physician-patient interaction and health outcome. METHODS: Sixty-seven FMS patients of an outpatient university setting that had been included in a randomized controlled trial were followed up. They were either treated in an SDM group or in an information group. Both groups saw a computer based information tool on FMS, but only the SDM group was treated by doctors which underwent a special SDM communication training. A comparison group of 44 FMS patients receiving treatment as usual was recruited in rheumatological practices. We assessed patients and their doctors using a combined qualitative and quantitative approach. Patients and doctors were followed-up after 3 months (T2) and after 1 year (T3). RESULTS: The significantly best quality of physician-patient interaction was reported by patients and doctors of the SDM group, followed by the information group. Coping had more often improved in the SDM group than in the information group. However directly health related outcome variables had not improved in any of the groups at T3. CONCLUSION: An SDM intervention can lead to an improved physician-patient relationship from the patients' and from the doctors' perspective. PRACTICE IMPLICATIONS: It should be considered to include SDM in standard care for FMS patients.

A computer-based information-tool for chronic pain patients. Computerized information to support the process of shared decision-making.

OBJECTIVE: Assessment of the use of a computerized information-tool in the context of a shared decision-making process with chronic pain patients. METHODS: In the scope of a prospective and randomized study on shared decision-making with Fibromyalgia patients, a total of 75 patients had access to computer-based information about their illness. Fibromyalgia is a condition of chronic wide-spread pain, belonging to rheumatism, which mainly affects mature female patients. The majority of the patients in our study are female (93%) with an average age of 50 years. The computer-based information-tool provided the patients with detailed information about pathogenesis, typical symptoms, treatment options and prognosis. Six evaluative questions were posed to the participants concerning the assessment of the information presented, the handling of the programme, the need for an introduction to the programme, the quality of the layout and the assessment of the length of time spent in front of the computer and the assessment of the usefulness of such a tool in general practitioners' offices. Furthermore, psychological self-assessment questionnaires were filled out by the participants. RESULTS: The patients highly appreciate the possibility of using computer-based information-tools and endorse the implementation of such tools in general practitioners' offices. CONCLUSION: Computerized information leads to a better understanding of the illness and the treatment options on the part of the patient. PRACTICAL IMPLICATIONS: For further practical use it is crucial to provide an introduction to the handling of a computer to unskilled patients.

[The process of shared decision making in chronic pain patients. Evaluation and modification of treatment decisions]. / Der Prozess der partizipativen Entscheidungsfindung bei chronischen Schmerzpatienten. Evaluation und Modifikation von Therapieentscheidungen.

Conditions affecting the musculoskeletal system are the cause of approximately 25% of absenteeism from work. Fibromyalgia syndrome is an exemplary condition of chronic widespread pain which most physicians consider difficult to manage. The physician-patient relationship is burdened with resignation and frustration on both sides. Initial agreement regarding the aims of treatment is rare. The patient's active involvement in the decision making process is expected to improve the physician-patient relationship. One aspect of this shared decision making process is the evaluation and possibly modification of treatment decisions. In the present study 39 consultations of physicians who had undergone special communication training were examined as to whether these physicians actually exercised the option of revising their treatment decisions. In 87.2% of the consultations the therapy decisions were modified within three months after the first encounter. Patients considered to be "difficult" were less likely to modify their decisions. The shared decision making process usually takes more than one consultation.

TorsinA protects against oxidative stress in COS-1 and PC12 cells.

Dystonia is a highly frequent movement disorder, the pathogenesis of which remains unclear. The cloning of TorsinA, the gene responsible for early-onset dystonia, was a major breakthrough. However, the function of this protein remains unclear. By sequence homology, TorsinA belongs to the ATPases associated with diverse cellular activities-family, many of whose members are chaperones and/or proteases. We report here that in an in vitro model for oxidative stress, H2O2 treatment, overexpression of TorsinA was protective against cell death. COS-1 cells overexpressing TorsinA demonstrated drastically reduced terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling-staining following exposure to H2O2. Furthermore, transfection with TorsinA significantly increased survival of PC12 after H2O2 treatment. To our knowledge, this is the first demonstration that TorsinA protects against oxidative stress. We speculate that a loss of this cellular function in mutant TorsinA may be linked to the pathogenesis of early-onset dystonia.