Arthurs OJ, Boniface S. How well do we understand the neural origins of the fMRI BOLD signal? Trends Neurosci 2002;25:27–31. Meyer RA, Treede RD. Mechanisms of secondary hyperalgesia: a role for myelinated nociceptors in punctate hyperalgesia. In: Brune K, Handwerker HO, editors. Hyperalgesia: molecular mechanisms and clinical implications. Seattle: IASP Press; 2004. Serra J, Campero M, Bostock...

Hyperalgesia may be defined as a state of increased intensity of pain sensation induced by either noxious or ordinarily non-noxious stimulation of peripheral tissue. Hyperalgesia occurs in both superficial and deep tissues, in areas with pain thresholds that are normal, lowered or raised (1, 2). As seen at the bedside there are apparently several varieties of hyperalgesia, and few clinical phen...

BACKGROUND Experimental studies and clinical observations suggest a possible role for opioids to induce pain and hyperalgesia on withdrawal. The authors used a new experimental pain model in human skin to determine the time course of analgesic and hyperalgesic effects of the mu-receptor agonist remifentanil alone or in combination with the N-methyl-D-aspartate-receptor antagonist S-ketamine or ...

INTRODUCTION Development of secondary hyperalgesia following a cutaneous injury is a centrally mediated, robust phenomenon. The pathophysiological role of endogenous opioid signalling to the development of hyperalgesia is unclear. Recent animal studies, carried out after the resolution of inflammatory pain, have demonstrated reinstatement of tactile hypersensitivity following administration of ...

BACKGROUND Hyperalgesia and neuroinflammation are associated with glia, which consists of macroglia and microglia. In this study, we used a selective cannabinoid receptor type 2 (CB2) agonist JWH015 to investigate remifentanil-induced postoperative hyperalgesia. METHODS Mechanical allodynia and thermal hyperalgesia after postoperative hyperalgesia and intrathecal injection of JWH015 were asse...

Effects of morphine and ketamine (NMDA receptor antagonist) on temporally summated pain ('wind-up-like pain') and spatial aspects of secondary hyperalgesia were investigated in 12 healthy volunteers. Hyperalgesia was produced by a local 1 degree burn injury covering 12.5 cm2 on the medial surface of the calf. Primary hyperalgesia was determined by measuring heat pain detection threshold (HPDT) ...

background: rheumatoid arthritis is a type of inflammatory pain and is an autoimmune and chronic inflammatory disease which can lead to hyperalgesia, edema and decreased motor activity in affected area. mesenchymal stem cells conditioned medium (msc-cm) has anti-inflammatory mediators which can regulate the immune responses, alleviate inflammatory symptoms and has a paracrine effects too. the a...

BACKGROUND To determine the mechanisms of postoperative pain, the effects of local anesthesia on development and maintenance of surgical incision-induced hyperalgesia were evaluated in a crossover, double-blinded, placebo-controlled human study using 17 subjects. METHODS An experimental 4-mm-long incision through skin, fascia, and muscle was made in the volar forearm of each subject. In exper...

BACKGROUND Discrepancies exist between osteoarthritic joint changes and pain severity before and after total hip (THR) and knee (TKR) replacement. This study investigated whether the interaction between pre-operative widespread hyperalgesia and severity of radiographic osteoarthritis (OA) was associated with pain severity before and after joint replacement. METHODS Data were analysed from 232...

Chronic migraine is a disabling condition that affects hundreds of millions of individuals worldwide. The development of novel migraine treatments has been slow, in part as a result of a lack of predicative animal models. We have developed a new model of chronic migraine involving the use of nitroglycerin (NTG), a known migraine trigger in humans. Chronic intermittent administration of NTG to m...