Pain
-
This study examined whether marital functioning variables related uniquely to psychological distress and diagnoses of depressive disorder independent of pain severity and physical disability. Participants were 110 chronic musculoskeletal pain patients. Hierarchical regression results showed that marital variables (i.e. marital satisfaction, negative spouse responses to pain) contributed significantly to depressive and anxiety symptoms over and above the effects of pain severity and physical disability. ⋯ In multivariate analyses, physical disability and marital satisfaction were uniquely related to depressive symptoms whereas physical disability, pain severity, and negative spouse responses to pain were uniquely related to anxiety symptoms. Only physical disability was uniquely related to major depression. The results suggest that models of psychological distress in chronic pain patients might be enhanced by attributing greater importance to interpersonal functioning and increasing attention to anxiety.
-
Acceptance of chronic pain entails that an individual reduce unsuccessful attempts to avoid or control pain and focus instead on participation in valued activities and the pursuit of personally relevant goals. Recent research suggests that pain-related acceptance leads to enhanced emotional and physical functioning in chronic pain patients above and beyond the influence of depression, pain intensity, and coping. In these studies, acceptance was measured using the Chronic Pain Acceptance Questionnaire (CPAQ). ⋯ The present study sought to further refine the CPAQ by examining its factor structure and evaluating the relations of these factors to other indices of pain-related distress and disability. Although a previously demonstrated factor structure of the CPAQ was generally supported, only factors assessing (a) the degree to which one engaged in life activities regardless of the pain and (b) willingness to experience pain had adequate reliability and validity and were significantly related to the other measures of patient functioning. A revised version of the CPAQ is suggested.
-
Comparative Study
Disengagement from pain: the role of catastrophic thinking about pain.
This paper reports an experimental investigation of attentional engagement to and disengagement from pain. Thirty-seven pain-free volunteers performed a cueing task in which they were instructed to respond to visual target stimuli, i.e. the words 'pain' and 'tone'. Targets were preceded by pain stimuli or tone stimuli as cues. ⋯ However, we also found that participants high in pain catastrophizing had difficulty disengaging from pain, whereas participants low in pain catastrophizing showed no retarded disengagement from pain. Our results provide further evidence that catastrophic thinking enhances the attentional demand of pain, particularly resulting in difficulty disengaging from pain. The clinical implications of these findings are discussed.
-
Comparative Study
Novel mechanism of enhanced nociception in a model of AIDS therapy-induced painful peripheral neuropathy in the rat.
To elucidate the underlying mechanisms involved in AIDS therapy-induced peripheral neuropathy, we have developed a model of nucleoside analog reverse transcriptase inhibitor-induced painful peripheral neuropathy in the rat, using 2',3'-dideoxycytidine (ddC), 2',3'-dideoxyinosine (ddI) and 2',3'-didehydro-3'-deoxythymidine (d4T), AIDS chemotherapeutic drugs that are also components of AIDS highly active anti-retroviral therapy. Administration of ddC, ddI and d4T produced dose-dependent mechanical hypersensitivity and allodynia. Peripheral administration of inhibitors of protein kinase A, protein kinase C, protein kinase G, p42/p44-mitogen-activated protein kinase (ERK1/2) and nitric oxide synthase, which have demonstrated anti-hyperalgesic effects in other models of metabolic and toxic painful peripheral neuropathies, had no effect on ddC-, ddI- and d4T-induced hypersensitivity. ⋯ Intradermal or spinal injection of intracellular calcium modulators (TMB-8 and Quin-2), which had no effect on nociception in control rats, significantly attenuated and together eliminated ddC and suramin-induced mechanical hypersensitivity. In electrophysiology experiments in ddC-treated rats, C-fibers demonstrated alterations in pattern of firing as indicated by changes in the distribution of interspike intervals to sustained suprathreshold stimuli without change in mechanical activation thresholds or in number of action potentials in response to threshold and suprathreshold stimulation. This study provides evidence for a novel, calcium-dependent, mechanism for neuropathic pain in a model of AIDS therapy-induced painful peripheral neuropathy.
-
Comparative Study
Cholinergic modulation of nociceptive responses in vivo and neuropeptide release in vitro at the level of the primary sensory neuron.
Muscarinic acetylcholine receptors (mAChRs) have been widely reported as pharmacological targets for the treatment of pain. However, most of these efforts have focused on CNS mAChRs and their role in modulating nociception at the level of the spinal cord. The present study examines the contribution of peripheral mAChRs in trigeminal nociceptive pathways using a combination of in vivo and in vitro approaches. ⋯ Finally, combined in situ hybridization/immunofluorescence demonstrated that m2 mRNA was present in 20% of trigeminal ganglion neurons between 30 and 60 microm in diameter and that 5-9% of these also expressed CGRP or VR1 immunoreactivity. These results show that activation of peripheral M2 receptors produces antinociception in vivo and the inhibition of nociceptor activity in vitro. While histological analyses at the level of the trigeminal neuronal cell bodies leave open the question of whether the effects of M2 agonists are direct or indirect, these data indicate that primary sensory neuronal M2 receptors may represent a viable peripheral target for the treatment of pain and inflammation.