Read by QxMD icon Read

Evoked response

Wadood Haq, Johannes Dietter, Sylvia Bolz, Eberhart Zrenner
OBJECTIVE: A feasibility study for a transmitter based subretinal prosthesis, generating visual responses in blind mouse retina is presented. APPROACH: Degenerated rd1 mouse retina were stimulated in subretinal configuration by local glutamate (Glu) or NMDA application via micropipettes (~1.5 μm) and thereby the outer retinal activity was recorded by calcium-imaging or the ganglion cell (GC) activity was recorded by the multi-electrode array system. The network mediated activation of GC via bipolar cells was approved by the administration of Glu receptor blockers...
June 19, 2018: Journal of Neural Engineering
Caoimhin S Griffin, Keith D Thornbury, Mark A Hollywood, Gerard P Sergeant
Acetylcholine contracts the bladder by binding to muscarinic M3 receptors on the detrusor, leading to Ca2+ influx via voltage-gated Ca2+ channels. The cellular mechanisms linking these events are poorly understood, but studies have suggested that activation of TRPC4 channels could be involved. The purpose of this study was to investigate if spontaneous and cholinergic-mediated contractions of the detrusor were impaired in TRPC4 deficient (TRPC4-/- ) mice. Isometric tension recordings were made from strips of wild-type (WT) and TRPC4-/- detrusor...
June 18, 2018: Scientific Reports
Dong Kyu Lee, Young Sil Min, Seong Su Yoo, Hyun Sub Shim, Sun Young Park, Uy Dong Sohn
A comprehensive collection of proteins senses local changes in intracellular Ca2+ concentrations ([Ca2+ ]i ) and transduces these signals into responses to agonists. In the present study, we examined the effect of sphingosine-1-phosphate (S1P) on modulation of intracellular Ca2+ concentrations in cat esophageal smooth muscle cells. To measure [Ca2+ ]i levels in cat esophageal smooth muscle cells, we used a fluorescence microscopy with the Fura-2 loading method. S1P produced a concentration-dependent increase in [Ca2+ ]i in the cells...
June 19, 2018: Biomolecules & Therapeutics
Samuel T Kissinger, Alexandr Pak, Yu Tang, Sotiris C Masmanidis, Alexander A Chubykin
Familiarity of the environment changes the way we perceive and encode incoming information. However, the neural substrates underlying this phenomenon are poorly understood. Here we describe a new form of experience-dependent low frequency oscillations in the primary visual cortex (V1) of awake adult male mice. The oscillations emerged in visually evoked potentials (VEPs) and single-unit activity following repeated visual stimulation. The oscillations were sensitive to the spatial frequency content of a visual stimulus and required the muscarinic acetylcholine receptors (mAChRs) for their induction and expression...
June 18, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Trine Andresen, Dagmar Lunden, Asbjørn M Drewes, Lars Arendt-Nielsen
Introduction and aim Pain sensitivity has been linked to the melanocortin-1 receptor (MC1R) gene. A mutation in MC1R can result in pale skin and red hair in humans and may modulate pain responses in general. Human studies have shown that women with non-functional MC1R's were sensitive to experimental induced cold and heat pain. A study demonstrated that females with red hair required higher dose of anesthesia than females with dark hair to experience analgesia to electrical stimulation. Moreover, women expressing non-functional MC1Rs display greater analgesia from opioid analgesia...
December 29, 2017: Scandinavian Journal of Pain
M Dusch, B Namer, M Strupf, M Schley, R Rukwied, B Hägglöf, M Schmelz, W Koppert
Background Anewexperimental protocol of electrically induced pain and hyperalgesia was established to examine orally administered drugs. In a randomized, double-blind, placebo-controlled cross-over study this experimental protocol was used to assess the effects of paracetamol. Methods Twenty-four subjects were enrolled in this study. The magnitude of pain, axon reflex flare, and areas of pin-prick hyperalgesia and touch-evoked allodynia were assessed in two consecutive sessions; prior to, and 2 h after drug administration...
December 29, 2017: Scandinavian Journal of Pain
F Petzke, K B Jensen, E Kosek, E Choy, S Carville, P Fransson, S C R Williams, H Marcus, Y Mainguy, M Ingvar, R H Gracely
Background In recent years, the prescription of serotonin-noradrenalin reuptake inhibitors (SNRIs) for treatment of fibromyalgia (FM) has increased with reports of their efficacy. The SNRI milnacipran is approved by the U.S. Food and Drug Administration (FDA) for treatment of FM, yet, the mechanisms by which milnacipran reduces FM symptoms are unknown. A large number of neuroimaging studies have demonstrated altered brain function in patients with FM but the effect of milnacipran on central pain processing has not been investigated...
December 29, 2017: Scandinavian Journal of Pain
Lise Gormsen, Flemming W Bach, Raben Rosenberg, Troels S Jensen
Background The definition of neuropathic pain has recently been changed by the International Association for the Study of Pain. This means that conditions such as fibromyalgia cannot, as sometimes discussed, be included in the neuropathic pain conditions. However, fibromyalgia and peripheral neuropathic pain share common clinical features such as spontaneous pain and hypersensitivity to external stimuli. Therefore, it is of interest to directly compare the conditions. Material and methods In this study we directly compared the pain modulation in neuropathic pain versus fibromyalgia by recording responses to a cold pressor test in 30 patients with peripheral neuropathic pain, 28 patients with fibromyalgia, and 26 pain-free age-and gender-matched healthy controls...
December 29, 2017: Scandinavian Journal of Pain
L Bittencourt da Silva, D Kulas, A Karshenas, B E Cairns, F W Bach, L Arendt-Nielsen, P Gazerani
Background/aims Analgesic effects of BoNTA develop within few hours in animal studies and within days in human studies. We have previously shown that BoNTA can block glutamate-induced mechanical sensitization and neurogenic vasodilation in rat temporalis muscle within 3 h. The present translational study was designed to explore the time-course of analgesic effects of BoNTA on pain, sensitization and vasomotor responses in a glutamateevoked human pain model. Methods BoNTA (5U) and saline were injected (30 min interval) into the left and right temporalis muscles of 12 healthy males (24...
December 29, 2017: Scandinavian Journal of Pain
Carina Graversen, Christina Brock, Jens Brøndum Frøkjær, Georg Dimcevski, Dario Farina, Asbjørn Mohr Drewes
Background/aims Electroencephalography (EEG) recorded as evoked brain potentials (EPs) reflects the cortical processing to an external event. This approach is often used to study the altered response to acute pain in chronic pain patients compared to healthy volunteers. However, discrimination of the responses from the study populations is a non-trivial task, which calls for improved objective methods. Methods To develop and validate a new methodology, we analyzed data from 16 type-1 diabetes mellitus patients and 15 age and gender matched volunteers, by means of brain activity recorded from 62 EEG channels...
December 29, 2017: Scandinavian Journal of Pain
Thomas Dahl Nissen, Carina Graversen, Steven Coen, Leif Hultin, Qasim Aziz, Jens Lykkesfeldt, Asbjørn Mohr Drewes, Christina Brock
Background In recent years only few novel drugs targeting visceral pain have been developed. This lack of success may be explained by animal models having poor predictive value. To increase the success of translating results from animals to humans there is a demand for comparable test models. The aim was to establish a comparable and reliable translational model to evoke mechanical rectal pain in rats and humans. Methods Mechanical rectal rapid balloon distension was done on two different days in 12 rats (separated by 24...
December 29, 2017: Scandinavian Journal of Pain
Christina Brock, Carina Graversen, Jens B Frøkjær, Eirik Søfteland, Massimiliano Valeriani, Asbjørn M Drewes
Background/aims Abnormal visceral sensory function in diabetes mellitus (DM) leads to neuronal changes in the enteric, peripheral and/or central nervous system (CNS). To explore the role of diabetic autonomic neuropathy (DAN) in patients with long-standing DM, we investigated psychophysical responses and neuronal activity recorded as evoked brain potentials (EPs) and dipolar source modelling. Methods Fifteen healthy volunteers and 14 type-1 DM patients with DAN were assessed with a symptom score index characterizing upper GI abnormalities...
December 29, 2017: Scandinavian Journal of Pain
Matias Nilsson, Thomas Dahl Nissen, Carina Graversen, Parisa Gazerani, Asbjørn Mohr Drewes, Christina Brock
Background and aims/objectives Offset analgesia (OA) is a newly discovered pain-inhibiting mechanism, defined as a disproportionately large decrease in pain perception in response to a decrease in noxious stimulus intensity. Offset analgesia is usually evoked using heat as noxious stimulus (44-47 °C) and a slight decrease (1 °C) in stimulus intensity causes the volunteers to be pain-free for 5-10 s, despite the presence of a constant noxious stimulus. The aim of the present study was to evaluate whether the OA phenomenon is reproducible within the same day and between different days in order to evaluate whether the phenomenon can be used as a prognostic/diagnostic tool or as a potential therapeutic target in pain treatment...
December 29, 2017: Scandinavian Journal of Pain
C S Madsen, B Johnsen, A Fuglsang-Frederiksen, T S Jensen, N B Finnerup
Background/aims Brief noxious heat stimuli activate Aδ and C fibers, and contact heat evoked potentials (CHEPs) can be recorded from the scalp. Under standard conditions, late responses related to AS fibers can be recorded. This study examines C-fiber responses to contact heat stimuli. Methods A preferential A-fiber blockade by compression to the superficial radial nerve was applied in 22 healthy subjects. Quality and intensity of heat evoked pain (NRS, 0-10), and CHEPs were examined at baseline, during nerve compression, and during further nerve compression with topical capsaicin (5%)...
December 29, 2017: Scandinavian Journal of Pain
Yuka Oono, Hongling Nie, Renata Lima Matos, Kelun Wang, Lars Arendt-Nielsen
Background and purpose Conditioned pain modulation (CPM) is a phenomenon in which pain is inhibited by heterotopic noxious stimulation. It is not known how the experimental condition affects the magnitude of the CPM response and the inter-and intra-individual variations. It is important to get the information of the test-retest reliability and inter-individual variations of CPM to apply CPM as a diagnostic tool or for screening analgesic compounds. This study evaluated (1) the magnitude of CPM, (2) the inter-individual coefficient of variation (inter-CV) and (3) the intra-individual coefficient of variation (intra-CV) to (A) different stimulus modalities to evoke CPM and (B) different assessment sites...
December 29, 2017: Scandinavian Journal of Pain
Per Hartvig Honoré, Anna Basnet, Laila Eljaja, Pernille Kristensen, Lene Munkholm Andersen, Signe Neustrup, Pia Møllgaard, Ole J Bjerrum
Introduction Animal disease models are predictive for signs seen in disease. They may rarely mimic all signs in a specific disease in humans with respect to etiology, cause or development. Several models have been developed for different pain states and the alteration of behavior has been interpreted as a response to external stimulus or expression of pain or discomfort. Considerable attention must be paid not to interpret other effects such as somnolence or motor impairment as a pain response and similarly not to misinterpret the response of analgesics...
December 29, 2017: Scandinavian Journal of Pain
Jens Brøndum Frøkjær, Søren Schou Olesen, Carina Graversen, Trine Andresen, Dina Lelic, Asbjørn Mohr Drewes
During the last decades there has been a tremendous development of non-invasive methods for assessment of brain activity following visceral pain. Improved methods for neurophysiological and brain imaging techniques have vastly increased our understanding of the central processing of gastrointestinal sensation and pain in both healthy volunteers as well as in patients suffering from gastrointestinal disorders. The techniques used are functional magnetic resonance imaging (fMRI), positron emission tomography (PET), electroencephalography (EEG)/evoked brain potentials (EPs), magnetoencephalography (MEG), single photon emission computed tomography (SPECT), and the multimodal combinations of these techniques...
December 29, 2017: Scandinavian Journal of Pain
Thomas Kronborg Larsen, Andreas Egmose, Marianne Enggaard, Rósa Hugosdóttir, Federico Arguissain, José Biurrun Manresa, Carsten Dahl Mørch
Introduction Offset analgesia (OA) is a temporal perceptual mechanism in which subjective pain ratings decrease disproportionally when a noxious heat stimulus is decreased by 1-3 ◦C. Whether OA is a peripheral, spinal or supraspinal mechanism remains unknown. The stimulation of afferent nociceptors in the foot, leads to a spinal nociceptive withdrawal reflex (NWR) which is mediated through the wide dynamic range (WDR) neurons and therefore under descending control. We hypothesized that OA affects the spinal nociceptive neurons resulting in an attenuation of the NWR during OA...
December 29, 2017: Scandinavian Journal of Pain
Caspar Skau Madsen, Nanna Brix Finnerup, Ulf Baumgärtner
Background and purpose Conventional neurophysiological techniques do not assess the function of nociceptive pathways and are inadequate to detect abnormalities in patients with small-fiber damage. This overview aims to give an update on the methods and techniques used to assess small fiber (Aδ- and C-fibers) function using evoked potentials in research and clinical settings. Methods Noxious radiant or contact heat allows the recording of heat-evoked brain potentials commonly referred to as laser evoked potentials (LEPs) and contact heat-evoked potentials (CHEPs)...
December 29, 2017: Scandinavian Journal of Pain
M Saarnilehto, M Pekkanen-Mattila, K Aalto-Setälä, O Silvennoinen, A Koivisto
Aims Aim of the study was to characterize functional ion channel and GPCR responses by using selective pharmacological tools and intracellular calcium imaging from human inducible pluripotent stem cell-derived sensory neurons. Methods Sensory neurons were generated from human keratinocytes that were reprogrammed to inducible pluripotent stem cells by using standard Yamanaka factors. Inducible pluripotent stem cells were differentiated into sensory neurons by using 2 differentiation protocols (small molecule and PA6 co-culture)...
December 29, 2017: Scandinavian Journal of Pain
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"