Insights into the mechanisms and the emergence of sex-differences in pain.

Recent studies describe sex and gender as critical factors conditioning the experience of pain and the strategies to respond to it. It is now clear that men and women have different physiological and behavioral responses to pain. Some pathological pain states are also highly sex-specific.

Multicomponent interdisciplinary group intervention for self-management of fibromyalgia: a mixed-methods randomized controlled trial.

Background: This study evaluated the efficacy of the PASSAGE Program, a structured multicomponent interdisciplinary group intervention for the self-management of FMS.

Methods: A mixed-methods randomized controlled trial (intervention (INT) vs. waitlist (WL)) was conducted with patients suffering from FMS.

Triggering Descending Pain Inhibition by Observing Ourselves or a Loved-One in Pain.

Objectives: Recent studies demonstrate that empathy-evoked brain responses include the activation of brainstem structures responsible for triggering descending pain inhibition. Unfortunately, direct evidence linking empathy for pain and descending inhibitory controls (conditioned pain modulation) is lacking. This study, therefore, aimed to determine if the observation of ourselves or a loved-one in pain could activate descending pain inhibition without exposure to a noxious stimulation; which is otherwise required.

Altered autonomic nervous system reactivity to pain in trigeminal neuralgia.

Background: In the past two decades, there has been increasing evidence to suggest that trigeminal neuralgia (TN) may be linked to a dysfunction of the autonomic nervous system (ANS). The aim of the present study was to formally test this hypothesis by comparing the reactivity of the ANS to experimental pain in a population of TN patients and healthy controls.

Methods: Twelve patients diagnosed with classical TN and 12 healthy controls participated in the study.

Placebo and nocebo: how to enhance therapies and avoid unintended sabotage to pain treatment.

SUMMARY There is good evidence showing that placebo and nocebo responses do not only reflect a psychological reappraisal of an unchanged nociceptive activity. There are several scientific evidences indicating that placebo or nocebo responses trigger changes in the brain that activate descending modulatory mechanisms, affecting the nociceptive signal early in the CNS. Among the psychological factors that trigger a placebo or nocebo response, conditioning and expectation have been demonstrated to greatly affect the outcomes of pain perception, but also the response to treatment.

Evaluation of the Bonapace Method: a specific educational intervention to reduce pain during childbirth.

Objective: As pain during childbirth is very intense, several educational programs exist to help women prepare for the event. This study evaluates the efficacy of a specific pain management program, the Bonapace Method (BM), to reduce the perception of pain during childbirth. The BM involves the father, or a significant partner, in the use of several pain control techniques based on three neurophysiological pain modulation models: (1) controlling the central nervous system through breathing, relaxation, and cognitive structuring; (2) using non-painful stimuli as described in the Gate Control Theory; and (3) recruiting descending inhibition by hyperstimulation of acupressure trigger points.

Pain inhibition is deficient in chronic widespread pain but normal in major depressive disorder.

Background: Given the complex relationships between fibromyalgia and major depressive disorder (MDD), it has been suggested that fibromyalgia is a "masked" MDD. In experimental settings, fibromyalgia is associated with lowered pain thresholds (hyperalgesia) and deficient pain inhibition. Similarly, it has been recently proposed that the proneness of patients with MDD to develop chronic pain results from a deficit in pain inhibition.

No relationship between the ins del polymorphism of the serotonin transporter promoter and pain perception in fibromyalgia patients and healthy controls.

Background: In animals, decades of research have shown that serotonin (5-HT) is involved in endogenous pain inhibition systems, which are deficient in chronic pain disorders such as fibromyalgia (FM). In humans, there is preliminary evidence showing that 5-HT is involved in the FM pathophysiology. In the current endophenotyping study, we sought to investigate, for the first time in humans, the relationships between the serotonin transporter promoter region (5-HTTLPR) polymorphism and experimentally-induced pain perception/inhibition in healthy controls (HC) and FM patients.

DRD3 Ser9Gly polymorphism is related to thermal pain perception and modulation in chronic widespread pain patients and healthy controls.

Unlabelled: Experimental studies showed that dopamine influences pain perception in healthy volunteers. Dopamine dysfunctions have been linked to the physiopathology of fibromyalgia (FM), which is associated with hyperalgesia and deficient pain inhibition. We sought to investigate the relationships between catecholamine-related polymorphisms [dopamine-D(3) receptor (DRD3) Ser9Gly and catechol-O-methyltransferase (COMT) Val158Met] and thermal pain measures in healthy subjects and FM patients.

Specificity of female and male sex hormones on excitatory and inhibitory phases of formalin-induced nociceptive responses.

Several factors have been proposed to account for the differences observed between men and women in pain perception. One of these is female and male gonadal hormones. In order to verify this assumption, a hormone replacement (pellets inserted subcutaneously) of (1) 17beta-estradiol, (2) progesterone, (3) 17beta-estradiol + progesterone or (4) testosterone have been performed in gonadectomized female and male Sprague-Dawley rats.

The role of sex hormones on formalin-induced nociceptive responses.

Many chronic pain conditions are more frequent in women than in men. This observation suggests that there is a potential role of sex hormones on pain perception. In the present study, we measured nociceptive responses to the formalin test in normal and gonadectomized male and female rats.

Combined effect of xenoestrogens and growth factors in two estrogen-responsive cell lines.

It is now well recognized that estrogenic signaling mechanisms are far more complex than once thought. Several crosstalks between the estrogen receptor and other signaling pathways may influence the estrogenic stimulation of cell growth. Thus, the estrogenic effects of several environmental contaminants, now suspected to act as endocrine disrupters, may be influenced by a simultaneous stimulation of other signaling pathways.