Search results for "Hyperalgesia"

Hyperalgesia and opioid switching

2005

Opioids, intended to abolish pain, can unexpectedly produce hyperalgesia, particularly during rapid opioid escalation. Opioid switching could be a therapeutic option in a condition of opioid-induced tolerance or hyperalgesia, but conversion ratios between opioids are difficult to apply in this context and require strict surveillance and expertise. This situation is challenging, because the rapid escalation of opioid doses, possibly due to the development of opioid-induced tolerance, can cause hyperalgesia. To avoid this adverse effect, clinicians need to refine their assessment of pain treatment and consider opioid switching. The authors present a case report in which switching from fentan…

Peripheral Acute Pain Mechanisms

1995

Many studies in several species, including humans, have identified a subset of primary afferent nerve fibres that are activated by potential or actual tissue-damaging stimuli. Discharge patterns of these nociceptive afferents faithfully reproduce some aspects of the applied stimuli (e.g. shape of the stimulus-response function) but not others (e.g. time-course of a sustained stimulus). Since primary nociceptive afferents provide the input to the central nervous system, their encoding properties have to be considered when studying central processing. On the other hand, pain perception correlates with some aspects of nociceptor discharges (e.g. fatigue with repetition of brief heat pulses), b…

Pain elicited by blunt pressure: neurobiological basis and clinical relevance.

2002

A new pyrazolo pyrimidine derivative inhibitor of cyclooxygenase-2 with anti-angiogenic activity

2003

In a previous study, we reported a new pyrazolo pyrimidine derivative, N(4)-benzyl-N(6),N(6)-dimethyl-1-1(tert-butyl)-1H-pyrazolo[3,4-d]pyrimidine-6,4-diamine (DPP), which inhibited potently cyclooxygenase-2 activity in intact cell assays with minor activity against cyclooxygenase-1 (IC(50)=0.9 nM for cyclooxygenase-2 versus IC(50)=59.6 nM for cyclooxygenase-1). In the present work, this behaviour was confirmed in vivo by using the 24-h zymosan-injected mouse air pouch model (ID(50)=1.36 nM/pouch for prostaglandin E(2) level). We also studied the possible beneficial effect of DPP in the angiogenesis-dependent murine air pouch granuloma and rat paw carrageenan-induced hyperalgesia models. DP…

TAFA4 relieves injury-induced mechanical hypersensitivity through LDL receptors and modulation of spinal A-type K+ current

2021

Pain, whether acute or persistent, is a serious medical problem worldwide. However, its management remains unsatisfactory, and new analgesic molecules are required. We show here that TAFA4 reverses inflammatory, postoperative, and spared nerve injury (SNI)-induced mechanical hypersensitivity in male and female mice. TAFA4 requires functional low-density lipoprotein receptor-related proteins (LRPs) because their inhibition by RAP (receptor-associated protein) dose-dependently abolishes its antihypersensitive actions. SNI selectively decreases A-type K+ current (IA) in spinal lamina II outer excitatory interneurons (L-IIo ExINs) and induces a concomitant increase in IA and decrease in hyperpo…

Chapter 35 Complex regional pain syndrome

2006

Publisher Summary This chapter describes complex regional pain syndrome (CRPS) as changes of muscles and bones distant from the primary tissue damage. It causes both acute pain and excitation of the sympathetic nervous system. The chapter classifies CRPS into two clinical types: the “primarily warm” type, which usually develops post-traumatically and in which skin temperature is increased on the affected side; and CRPS cases, which manifest with a cold skin from the beginning. This “primarily cold” type more often develops after minor trauma or even spontaneously. The chapter reviews that “primary cold” CRPS is harder to treat and tends to become chronic. Symptoms of CRPS are not stable; th…

Opioid Poorly-Responsive Cancer Pain. Part 2

2001

Basic research in experimental pain models may illuminate the phenomenon of cancer pain that is poorly responsive to opioid drugs. Research findings can be valuable in formulating new strategies in clinical practice. This review evaluated experimental observations in terms of the events that occur in cancer patients receiving opioid therapy for pain.

Manejo perioperatorio del dolor en el paciente en tratamiento crónico con opiáceos

2011

Pain is one of the most common reasons for seeking medical care and the frequency of prescription of opioid analgesics by both primary care physicians and specialists has increased. It is therefore unsurprising that many patients with chronic pain who must undergo scheduled or emergency surgery will be on long-term medication, including opioids. Managing postoperative pain, even with high doses of drugs, seems to be more difficult in regular users of such analgesics, possibly because of an apparent association of opioid use with increased tolerance and hyperalgesia. Postoperative pain relief should be carefully tailored in these cases by means of a management plan worked out along with the …

Human surrogate models of neuropathic pain.

2005

Neuropathic pain is defined as pain initiated or caused by a primary lesion or dysfunction in the nervous system (Merskey and Bogduk, 1994). Current efforts to refine this definition focus on the terms ‘dysfunction’ and ‘nervous system’ with the intention to clarify that there has to be an identifiable lesion or disease process affecting the somatosensory system. Experimental models of neuropathic pain according to either one of these definitions are expected to imitate mechanisms of nerve damage within the peripheral or central parts of the somatosensory system and the ensuing processes of degeneration and regeneration. Whereas this approach to model the etiology and pathophysiology of the…

The Underestimated Significance of Conditioning in Placebo Hypoalgesia and Nocebo Hyperalgesia

2018

Placebo and nocebo effects are intriguing phenomena in pain perception with important implications for clinical research and practice because they can alleviate or increase pain. According to current theoretical accounts, these effects can be shaped by verbal suggestions, social observational learning, and classical conditioning and are necessarily mediated by explicit expectation. In this review, we focus on the contribution of conditioning in the induction of placebo hypoalgesia and nocebo hyperalgesia and present accumulating evidence that conditioning independent from explicit expectation can cause these effects. Especially studies using subliminal stimulus presentation and implicit con…