BACKGROUND: Quantitative sensory testing (QST) assesses the functional integrity of small and large nerve fibre afferents and central somatosensory pathways; QST was assumed to provide insight into the mechanisms of neuropathy. We analysed QST profiles and phenotypes in patients with diabetes mellitus to study whether these could differentiate patients with and without pain and neuropathy. METHODS: A standardized QST protocol was performed and 'loss and gain of function' abnormalities were analysed in four groups of subjects: diabetic patients with painful (pDSPN; n = 220) and non-painful distal symmetric polyneuropathy (nDSPN; n = 219), diabetic patients without neuropathy (DM; n = 23) and healthy non-diabetic subjects (n = 37). Based on the QST findings, diabetic subjects were further stratified into four predefined prototypic phenotypes: sensory loss (SL), thermal hyperalgesia (TH), mechanical hyperalgesia (MH) and healthy individuals. RESULTS: Patients in the pDSPN group showed the greatest hyposensitivity ('loss of function'), and DM patients showed the lowest, with statistically significant increases in thermal, thermal pain, mechanical and mechanical pain sensory thresholds. Accordingly, the frequency of the SL phenotype was significantly higher in the pDSPN subgroup (41.8%), than expected (p < 0.0042). The proportion of 'gain of function' abnormalities was low in both pDSPN and nDSPN patients without significant differences. CONCLUSIONS: There is a continuum in the sensory profiles of diabetic patients, with a more pronounced sensory loss in pDSPN group probably reflecting somatosensory nerve fibre degeneration. An analysis of 'gain of function' abnormalities (allodynia, hyperalgesia) did not offer a key to understanding the pathophysiology of spontaneous diabetic peripheral neuropathic pain. SIGNIFICANCE: This article, using quantitative sensory testing profiles in large cohorts of diabetic patients with and without polyneuropathy and pain, presents a continuum in the sensory profiles of diabetic patients, with more pronounced 'loss of function' abnormalities in painful polyneuropathy patients. Painful diabetic polyneuropathy probably represents a 'more progressed' type of neuropathy with more pronounced somatosensory nerve fibre degeneration. The proportion of 'gain of function' sensory abnormalities was low, and these offer limited understanding of pathophysiological mechanisms of spontaneous neuropathic pain.
Hypersensitive pain response is observed in patients with Parkinson's disease (PD). However, the signal pathways leading to hyperalgesia still need to be clarified. Chronic oxidative stress is one of the hallmarks of PD pathophysiology. Since the midbrain periaqueductal gray (PAG) is an important component of the descending inhibitory pathway controlling on central pain transmission, we examined the role NADPH oxidase (NOX) of the PAG in regulating exaggerated pain evoked by PD. PD was induced by central microinjection of 6-hydroxydopamine to lesion the left medial forebrain bundle of rats. Then, Western Blot analysis and ELISA were used to determine NOXs and products of oxidative stress (i.e., 8-isoprostaglandin F2alpha and 8-hydroxy-2'-deoxyguanosine). Pain responses to mechanical and thermal stimulation were further examined in control rats and PD rats. In results, among the NOXs, protein expression of NOX4 in the PAG of PD rats was significantly upregulated, thereby the products of oxidative stress were increased. Blocking NOX4 pathway in the PAG attenuated mechanical and thermal pain responses in PD rats and this was accompanied with decreasing production of oxidative stress. In addition, inhibition of NOX4 largely restored the impaired GABA within the PAG. Stimulation of GABA receptors in the PAG of PD rats also blunted pain responses. In conclusions, NOX4 activation of oxidative stress in the PAG of PD rats is likely to impair the descending inhibitory GABAergic pathways in regulating pain transmission and thereby plays a role in the development of pain hypersensitivity in PD. Inhibition of NOX4 has beneficial effects on the exaggerated pain evoked by PD.
- MeSH
- bolest farmakoterapie etiologie metabolismus patologie MeSH
- fasciculus telencephali medialis účinky léků metabolismus MeSH
- GABA metabolismus MeSH
- krysa rodu rattus MeSH
- modely nemocí na zvířatech MeSH
- NADPH-oxidasa 4 antagonisté a inhibitory MeSH
- Parkinsonova nemoc enzymologie metabolismus patologie MeSH
- potkani Sprague-Dawley MeSH
- práh bolesti účinky léků fyziologie MeSH
- pyrazolony farmakologie MeSH
- pyridony farmakologie MeSH
- signální transdukce účinky léků MeSH
- substantia grisea centralis účinky léků metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
In recent years, epidemiological data has shown an increasing number of young people who deliberately self-injure. There have also been parallel increases in the number of people with tattoos and those who voluntarily undergo painful procedures associated with piercing, scarification, and tattooing. People with self-injury behaviors often say that they do not feel the pain. However, there is no information regarding pain perception in those that visit tattoo parlors and piercing studios compared to those who don't. The aim of this study was to compare nociceptive sensitivity in four groups of subjects (n=105, mean age 26 years, 48 women and 57 men) with different motivations to experience pain (i.e., with and without multiple body modifications) in two different situations; (1) in controlled, emotionally neutral conditions, and (2) at a "Hell Party" (HP), an event organized by a piercing and tattoo parlor, with a main event featuring a public demonstration of painful techniques (burn scars, hanging on hooks, etc.). Pain thresholds of the fingers of the hand were measured using a thermal stimulator and mechanical algometer. In HP participants, information about alcohol intake, self-harming behavior, and psychiatric history were used in the analysis as intervening variables. Individuals with body modifications as well as without body modifications had higher thermal pain thresholds at Hell Party, compared to thresholds measured at control neutral conditions. No such differences were found relative to mechanical pain thresholds. Increased pain threshold in all HP participants, irrespectively of body modification, cannot be simply explained by a decrease in the sensory component of pain; instead, we found that the environment significantly influenced the cognitive and affective component of pain.
- MeSH
- dospělí MeSH
- lidé MeSH
- měření bolesti metody psychologie MeSH
- mladiství MeSH
- mladý dospělý MeSH
- piercing psychologie MeSH
- práh bolesti fyziologie psychologie MeSH
- tetování psychologie MeSH
- vysoká teplota škodlivé účinky MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Behavioural synchronization has been shown to facilitate social bonding and cooperation but the mechanisms through which such effects are attained are poorly understood. In the current study, participants interacted with a pre-recorded confederate who exhibited different rates of synchrony, and we investigated three mechanisms for the effects of synchrony on likeability and trusting behaviour: self-other overlap, perceived cooperation, and opioid system activation measured via pain threshold. We show that engaging in highly synchronous behaviour activates all three mechanisms, and that these mechanisms mediate the effects of synchrony on liking and investment in a Trust Game. Specifically, self-other overlap and perceived cooperation mediated the effects of synchrony on interpersonal liking, while behavioural trust was mediated only by change in pain threshold. These results suggest that there are multiple compatible pathways through which synchrony influences social attitudes, but endogenous opioid system activation, such as β-endorphin release, might be important in facilitating economic cooperation.
- MeSH
- dospělí MeSH
- důvěra * MeSH
- endorfiny fyziologie MeSH
- interpersonální vztahy MeSH
- kooperační chování * MeSH
- lidé MeSH
- mladý dospělý MeSH
- postoj MeSH
- práh bolesti fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Úvod: Dynamické metody kvantitativního testování senzitivity (Quantitative Sensory Testing; QST) jsou relativně novou nadstavbovou aplikací QST umožňující objektivizovat funkci centrálních modulačních mechanizmů algické percepce, jejichž individuální nastavení může přispívat k rozvoji chronických bolestivých stavů. Testování těchto mechanizmů umožňuje např. predikci rozvoje pooperační bolesti. K nejčastěji hodnoceným dynamickým QST metodám patří tzv. podmíněná modulace bolesti (Conditioned Pain Modulation; CPM) a časová sumace percepce bolestivých podnětů (Temporal Summation; TS). Soubor a metodika: Vyšetření dQST (dynamic methods of Quantitative Sensory Testing) metod s využitím termoalgických podnětů a modulace bolestivým chladem bylo provedeno u 77 zdravých dobrovolníků (47 žen testovaných v ovulační fázi menstruačního cyklu, 30 mužů, věk 19–73 let). Hodnocen byl také vliv věku a pohlaví na výsledky obou dQST testů. Výsledky: Uspokojivá funkce podmíněné modulace bolesti byla prokázána u 84 % testovaných dobrovolníků. Časová sumace bolestivých podnětů byla zachycena u 92, resp. 98 % jedinců v závislosti na použité teplotě podnětů. Nefunkčnost mechanizmů u zbylé části souboru byla ve většině případů podmíněna nesprávně nastavenými technickými parametry testu. U žen testovaných v ovulační fázi menstruačního cyklu jsme prokázali signifikantně vyšší efektivitu CPM mechanizmu ve srovnání s muži. Funkce TS se mezi oběma pohlavími významně nelišila. Významný vliv věku na efektivitu CPM ani TS mechanizmu nebyl ve sledovaném souboru prokázán. Závěr: Provedená studie ověřila použitelnost zvolených algoritmů dynamického testování senzitivity a prokázala antinociceptivní nastavení žen v ovulační fázi menstruačního cyklu ve srovnání s muži, zatímco významný vliv věku na funkci centrálních modulačních mechanizmů algické percepce nebyl zachycen.
Background: So called “dynamic quantitative sensory methods” (dQST) represent relatively new QST application which enables to objectify certain mechanisms of pain processing, e.g. central integration or descending control. Their dysfunction may contribute to the development of chronic painful conditions. dQST methods proved the potential to predict the development of chronic postoperative pain. Conditioned pain modulation (CPM) and temporal summation (TS) are the most commonly used dQST tests. Patients and methods: The CPM and TS testing was performed in a group of 77 healthy volunteers (47 women tested in the ovulatory phase of the menstrual cycle, 30 men, age range 19–73) using thermal pain stimuli. Efficiency of CPM and TS mechanism including age and gender influence was evaluated. Results: Efficient CPM was found in 84% of healthy volunteers. In remaining 16%, the inefficiency was mainly due to low intensity of testing or modulatory stimuli. Based on the temperature used, efficient TS mechanism was found in 92% or 98% of healthy individuals. Women in the ovulatory phase of the menstrual cycle showed significantly more efficient CPM comparing to men. No sex differences of TS testing were found. Age had no significant effect on the CPM or TS mechanism in our group of healthy voluteers. Conclusions: Our study has verified the applicability of CPM and TS algorithms used. Women in ovulatory phase of the menstrual cycle show increased anti-nociceptive setting comparing to men. No significant effect of age on central modulation of pain perception has been found in pain-free healthy individuals. Key words: pain perception – nociceptive pain – neuropathic pain – temporal summation – conditioned pain modulation – pain measurement – sex factors – age factors The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE “uniform requirements” for biomedical papers.
- MeSH
- algoritmy MeSH
- bolest * klasifikace MeSH
- časové faktory MeSH
- diagnostické techniky neurologické * MeSH
- dospělí MeSH
- fyzikální stimulace metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- ovulace MeSH
- percepce bolesti fyziologie klasifikace MeSH
- práh bolesti fyziologie klasifikace MeSH
- prediktivní hodnota testů MeSH
- reprodukovatelnost výsledků MeSH
- senioři MeSH
- senzorické prahy * fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
BACKGROUND: Nociception in rats is frequently measured in terms of latency of withdrawal reaction to radiant heat (thermal nociceptive threshold). The aim of this study was to determine how much housing acclimatization and ambient temperature affect the results of thermal pain threshold testing. METHODS: All experiments used adult male Wistar rats. Thermal pain thresholds were tested using the radiant heat withdrawal reaction at three different body sites: forepaws, hind paws and tail. Skin temperature was measured using an Infrared thermometer and ambient temperature was set at 18, 20, 24 or 26 °C. RESULTS: The results demonstrate that (1) thermal pain threshold was inversely related to both ambient and skin temperature; (2) housing acclimatization and repeated testing had no effect on nociceptive thresholds at any of the three body sites; (3) a resting, cranio-caudal distribution, of nociceptive sensitivity was observed; (4) hind paws and tail were more sensitive to changes of skin and ambient temperature than forepaws. CONCLUSION: These findings show the importance of recording laboratory conditions in experiments and their influence on results.
- MeSH
- aklimatizace fyziologie MeSH
- bolest patofyziologie MeSH
- fyzikální stimulace MeSH
- krysa rodu rattus MeSH
- měření bolesti MeSH
- potkani Wistar MeSH
- práh bolesti fyziologie MeSH
- reakční čas fyziologie MeSH
- teplota kůže MeSH
- teplota * MeSH
- vysoká teplota MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- bolest etiologie farmakoterapie klasifikace komplikace MeSH
- chronická nemoc farmakoterapie terapie MeSH
- diabetické neuropatie farmakoterapie komplikace MeSH
- kapsaicin farmakokinetika farmakologie terapeutické užití MeSH
- kationtové kanály TRPV účinky léků MeSH
- lidé MeSH
- mechanoreceptory * fyziologie účinky léků MeSH
- mononeuropatie farmakoterapie komplikace MeSH
- nádory komplikace MeSH
- nedostatek vitaminu D komplikace metabolismus MeSH
- nervové receptory fyziologie účinky léků MeSH
- patologie metody trendy MeSH
- práh bolesti fyziologie účinky léků MeSH
- vrozené, dědičné a novorozenecké nemoci a abnormality farmakoterapie komplikace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- Klíčová slova
- tenzní typ bolesti hlavy a jeho léčba, palpační citlivost, prahy bolesti, periferní a centrální mechanismy,
- MeSH
- akutní bolest etiologie patofyziologie terapie MeSH
- analgetika aplikace a dávkování klasifikace terapeutické užití MeSH
- antirevmatika aplikace a dávkování klasifikace terapeutické užití MeSH
- chronická bolest etiologie patofyziologie terapie MeSH
- klinické zkoušky jako téma MeSH
- lidé MeSH
- nervus trigeminus patologie MeSH
- neurologické manifestace MeSH
- oxid dusnatý antagonisté a inhibitory sekrece MeSH
- práh bolesti fyziologie klasifikace psychologie MeSH
- psychický stres patologie prevence a kontrola MeSH
- tenzní bolesti hlavy * diagnóza etiologie klasifikace patofyziologie prevence a kontrola terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
OBJECTIVES: Anorexia nervosa (AN) patients represent a natural model of relationship between changed hormonal level and pain perception due to lower level of sex hormones and consistently described increased pain threshold. As the adrenal stress steroid hormones (cortisol and DHEA) are known to be also changed in AN (and share a common precursor), our study was aimed to analyze the association between these hormones and pain perception in AN patients and control healthy women. METHODS: The pain threshold latencies to radiant heat stimuli were measured in 20 DSM-IV diagnosed patients with AN and in 21 healthy women. Blood samples were collected in the morning hours and analyses of the plasma levels of dehydroepiandrosterone (DHEA), its conjugated sulfate ester (DHEA-S) and cortisol were implemented. RESULTS: Thermal pain threshold was higher in AN than in healthy women and correlated negatively with the level of DHEA and positively with cortisol/DHEA(S) ratio. No significant correlation between thermal pain and hormones was found in healthy women. If both groups were pooled together, the rest pain threshold correlated negatively with DHEA-S (r=-0.42, p=0.008). CONCLUSION: We showed for the first time that sensitivity to thermal pain in women is dependent on DHEA-S and on cortisol/DHEA(S) ratio in patients with AN.
- MeSH
- analýza párové shody MeSH
- dehydroepiandrosteron krev MeSH
- dehydroepiandrosteronsulfát krev MeSH
- dospělí MeSH
- hydrokortison krev MeSH
- lidé MeSH
- mentální anorexie krev patofyziologie MeSH
- mladý dospělý MeSH
- neparametrická statistika MeSH
- nocicepce fyziologie MeSH
- práh bolesti fyziologie MeSH
- referenční hodnoty MeSH
- studie případů a kontrol MeSH
- vysoká teplota MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
