The present study investigated differences between opioids to experimental tonic pain in healthy men. Twenty-one males participated this cross-over-trial. Interventions twice daily were oxycodone (10 mg), tapentadol (50 mg) and placebo for 14 days. Tonic was induced on day 1, 4 by immersing the hand 2 °C water 120 s. Electroencephalography recorded during test at baseline after Spectral analysi...

the involvement of supraspinal alpha-adrenergic receptors in tonic pain was assessed in formalin-induced pain in rats. the alpha2 adrenoceptor agonist clonidine, along with yohimbine and prazosin, α2 and α1 receptor antagonists, were introduced intracerebroventrically (icv) and/or systemically in different doses. the data show that 1) clonidine exerts an alpha adrenergic analgesic effect, in ad...

In this study, the effects of subcutaneous (SC) injection of pilocarpine (a cholinomimetic agent) and atropine (a muscarinic receptors antagonist) were investigated on a tonic model of orofacial pain in rats. The contribution of the endogenous analgesic opioid system was assessed using naloxone (an opioid receptors antagonist). Tonic orofacial pain was induced by SC injection of a diluted forma...

The involvement of supraspinal alpha-adrenergic receptors in tonic pain was assessed in formalin-induced pain in rats. The alpha2 adrenoceptor agonist clonidine, along with yohimbine and prazosin, α2 and α1 receptor antagonists, were introduced intracerebroventrically (icv) and/or systemically in different doses. The data show that 1) clonidine exerts an alpha adrenergic analgesic effect, ...

Under physiological conditions, momentary pain serves vital protective functions. Ongoing pain in chronic pain states, on the other hand, is a pathological condition that causes widespread suffering and whose treatment remains unsatisfactory. The brain mechanisms of ongoing pain are largely unknown. In this study, we applied tonic painful heat stimuli of varying degree to healthy human subjects...

There is substantial evidence that men and women differ in their perception and experience of pain. However, research on sex differences in pain has mainly relied on self-report ratings, whereas little is known about sex differences in facial expression of pain. The aim of the present study was to investigate: 1) whether men and women differ in their facial expressiveness of pain; and 2) whethe...

The relationship between pain and cognitive function is of theoretical and clinical interest, exemplified by observations that attention-demanding activities reduce pain in chronically afflicted patients. Previous studies have concentrated on phasic pain, which bears little correspondence to clinical pain conditions. Indeed, phasic pain is often associated with differential or opposing effects ...

Placebo exhibits beneficial effects on pain perception in human experimental studies. Most of these studies demonstrate that placebo significantly decreased neural activities in pain modulatory brain regions and pain-evoked potentials. This study examined placebo analgesia-related effects on spontaneous brain oscillations. We examined placebo effects on four order-fixed 20-min conditions in two...