Emotional Component Of Pain Research Articles

CS11 Pain in the absence of nociception: example from empathy

CS11 Pain in the absence of nociception: example from empathy

Persistent Pain Produces Stress-like Alterations in Hippocampal Neurogenesis and Gene Expression

Clinical observations have shown that patients with chronic pain are often depressed, suggesting the importance of the affective or emotional component of pain and its impact on cognition. In this study we investigated pain-induced activation of the hippocampus to address possible molecular and cellular events that may underlie the comorbidity of chronic pain and depression. Rats received either an acute (formalin) or chronic (complete Freund’s adjuvant) inflammatory stimulus to the hind paw or an acute or chronic immobilization. Results demonstrated that pain can alter hippocampal morphology and gene expression. Bromodeoxyuridine (BrdU) staining indicated that neurogenesis in the hippocampal dentate gyrus was significantly reduced after long-term inflammatory nociception, similar to previous observations after various stress models. Important activators of nociception-induced spinal central sensitization, the neurokinin-1 (NK-1) receptor and brain-derived neurotrophic factor (BDNF), have also been intimately associated with depressive processes in the limbic system. In situ hybridization assay results demonstrated that either pain or stress (acute or chronic treatments) reduced the levels of both NK-1 receptor and BDNF mRNAs in the cornu ammonis 1-3 sublayers of the hippocampus, suggesting a possible role of these neuromediators in processing of pain in higher brain centers. Perspective The findings in this study demonstrate that persistent pain induces stress-like damaging modulatory effects in the hippocampus, which is one of the limbic regions involved in the pathophysiology of depression. Targeting these mechanisms (which are potential contributors to the emotional impact of pain) may provide novel therapeutic approaches for relieving depression-like aspects of chronic pain.

Topographic analysis of laser evoked potentials in chronic tension-type headache: Correlations with clinical features

In the present study, we examined clinical and laser-evoked potentials (LEP) features in a group of chronic tension-type headache (CTTH) patients, in order to perform a topographic analysis of Laser evoked potentials (LEPs) and a correlation with clinical features. Eighteen patients suffering from CTTH [Headache Classification Subcommittee of the International Headache Society. The International Classification of Headache Disorders 2nd ed. Cephalalgia 2004; 24 Suppl 1, 1–159.] participated in the study. Twelve age- and sex-matched controls were also examined. We performed a basal evaluation of clinical features, Total Tenderness Score (TTS) and a topographic analysis of LEPs obtained by the hand and the pericranial points stimulation in all patients vs healthy subjects. The later LEPs, especially the P2 component, were significantly increased in amplitude in the CTTH group, specially when the pericranial points were stimulated. The P2 wave amplitude was correlated with TTS levels and anxiety scores. The results of this study confirm that pericranial tenderness is a phenomenon initiating a self-sustaining circuit, involving central sensitization at the level of the cortical nociceptive areas devoted to attentional and emotional components of pain.

Branching patterns of parabrachial neurons projecting to the central extended amgydala: Single axonal reconstructions

Electrophysiological evidence suggests that the spinoparabrachioamygdaloid pathway carries nociceptive information that may be important for the elaboration of physiological and emotional responses to noxious events. The pontine parabrachial nucleus (pPB) sends a massive projection to the central nucleus of the amygdala (CeA) and lateral bed nucleus of the stria terminalis (BSTL), both regions belonging to a broader macrostructure, the central extended amygdala (EAc). The aim of this study was to examine whether different EAc components are targeted by a same pPB neuron, by reconstructing single axonal branching patterns after anterograde labelling. Small deposits of biotinylated dextran amine in the region of the external lateral pPB result in dense and specific labelling in the whole EAc. Reconstructed axons innervate either the lateral or the capsular part of the CeA with perisomatic or bushy terminals, respectively. A subset of axons enters the stria terminalis rostrally to follow its trajectory caudally toward the CeA. Individual axons targeting the CeA usually send collaterals to other EAc components, especially those projecting to the lateral CeA, which often coinnervate the BSTL. By contrast, only few branches were found outside the EAc. These results suggest that the noxious information travelling from the pPB to the CeA may also be transmitted to other EAc components. This pPB-EAc pathway, which appears distinct from the parabrachiohypothalamic and parabrachiothalamic projections, would be the anatomical basis through which the EAc elaborates the autonomic, endocrine, and emotional components of pain.

MINDING GOD/MINDING PAIN: CHRISTIAN THEOLOGICAL REFLECTIONS ON RECENT ADVANCES IN PAIN RESEARCH

Abstract. As Gregory Peterson's book Minding God illustrates, an ongoing encounter between theology and the cognitive sciences can provide rich insights to both disciplines. Similarly, reflection on recent advances in pain research can prove to be fertile ground in which further theological insights might take root. Pain researchers remind us that pain is both a sensory and an emotional experience. The emotional component of pain is critically important for the clinical management of people in pain, as it serves a communicative function—human connection occurs more readily through the expression of and response to emotion than through the sterile exchange of “objective” descriptions of sensory phenomena. But emotion, pain and communication also figure prominently in Christian theology. For example, doctrines of incarnation and eschatology raise questions about suffering, healing, and hope as well as about the nature of the divine–human relationship. In addition, there seems to be scientific evidence for (admittedly subtle) gender differences in the perception of and response to pain. Several feminist theologians have noted that a habitual theological emphasis on God's rationality tends to reinforce masculine images of God and demeans the validity of emotion in the divine‐human relationship. Potential theological implications of the emotional and communicative aspects of pain and how this might affect women's religious experience‐with a particular focus on Teresa of Avila‐are explored.

Peripheral axotomy increases cholecystokinin release in the rat anterior cingulate cortex

The anterior cingulate cortex (ACC) is a limbic region with a high density of cholecystokinin (CCK) immunoreactivity, that has been suggested to be of importance for the affective and emotional component of pain. In the present microdialysis study, performed in the awake rat, we demonstrate a bilateral 4- to 6-fold increase of the potassium-induced release of CCK-like immunoreactivity (CCK-LI) in the ACC 2-3 weeks after a unilateral transection of the sciatic nerve (axotomy), an animal model of phantom limb or deafferentiation pain. Considering the implication of CCK in pain modulation and anxiety, we suggest that an altered activity of CCK containing neurons in the ACC may be of importance for the affective component of certain pain conditions.

Prevention and control of pain in children

The development of pain pathways and stress responses in the fetus, neonate, infant and child has been elucidated recently and has led to widespread acceptance that for moral, ethical, humanitarian and physiological reasons, pain should be anticipated, and safely and effectively prevented and controlled in all age groups. 5 6 20 21 27 32 71 77 78 83 86 Simple measures, widely applied, produce the most benefit at the least risk. For more complex techniques, a minimum standard of monitoring should be implemented and regular reassessment of analgesia and adverse effects allow individualized titration of analgesia. Routine perioperative use of local or regional anaesthesia in all children, unless there is a specific contraindication, is the foundation of effective postoperative analgesia. A multimodal approach using local and regional anaesthesia, opioids and nonsteroidal anti-inflammatory drugs (NSAID)/paracetamol is particularly useful in paediatrics. The emotional component of pain must also be addressed in all aspects of paediatric practice using instinctive comforting measures, provision of child-friendly surroundings and distraction techniques. The child and family should be given the chance to be involved in the control of their pain management. These non-pharmacological techniques should be used to complement safe and effective use of analgesic drugs.

Effect of analgesics on audible and ultrasonic pain-induced vocalization in the rat

Brief electrical pulses applied to the rat tail elicit a complex vocal response which includes audible (peeps, chatters) and ultrasonic (USV) components. Aspirin and amitriptyline had no effect on the vocal responses. Morphine showed a dose-dependent and naloxone reversible antinociceptive effect on the 1st and 2nd audible peeps by decreasing their intensity (evaluated by their envelopes which correspond to the outer bounds of the soundwave amplitude plotted as a function of time), with ED 50 values of 1.96 mg/kg and 0.36 mg/kg I.V. Respectively. Paracetamol significantly reduced only the intensity of the second peep at the dose of 200 mg/kg iv. Chatter intensity was decreased by doses of 1 and 3 mg/kg I.V. Of morphine which would suggest an effect on emotional components of pain. The intensity of USV was affected by morphine injection although the variations observed were non-significant. These data clearly implicate a specific role for the opioid analgesics in modifying the vocal pain related behaviors.

Prevention and control of pain in children

The development of pain pathways and stress responses in the fetus, neonate, infant and child has been elucidated recently and has led to widespread acceptance that for moral, ethical, humanitarian and physiological reasons, pain should be anticipated, and safely and effectively prevented and controlled in all age groups. 5 6 20 21 27 32 71 77 78 83 86 Simple measures, widely applied, produce the most benefit at the least risk. For more complex techniques, a minimum standard of monitoring should be implemented and regular reassessment of analgesia and adverse effects allow individualized titration of analgesia. Routine perioperative use of local or regional anaesthesia in all children, unless there is a specific contraindication, is the foundation of effective postoperative analgesia. A multimodal approach using local and regional anaesthesia, opioids and nonsteroidal anti-inflammatory drugs (NSAID)/paracetamol is particularly useful in paediatrics. The emotional component of pain must also be addressed in all aspects of paediatric practice using instinctive comforting measures, provision of child-friendly surroundings and distraction techniques. The child and family should be given the chance to be involved in the control of their pain management. These non-pharmacological techniques should be used to complement safe and effective use of analgesic drugs.

Emotional Components of Pain

BACKGROUND: Current definitions of pain suggest that emotion is an essential component of pain, however, the presumed relationship between emotion and pain, and the specific emotions that are involved in pain experiences have yet to be clarified.OBJECTIVE: To address these issues in order to assist in making current conceptualizations of pain more explicit.DESIGN: Thirty adult patients undergoing routine blood tests were videotaped. Spontaneous facial reactions were examined for distinct expressions of emotion and pain occurring at baseline, swabbing and venepuncture intervals. Expressions were assessed objectively with the Facial Action Coding System (FACS) and rated subjectively by 48 untrained judges. Patients also provided baseline and postneedle self‐reports of experienced pain.RESULTS: Comparison of venepuncture, swabbing and baseline segments revealed that objective measures of pain‐related facial activity, subjective ratings of pain expression and self‐reported ratings of pain increased significantly from baseline to venepuncture and that measures of disgust, anger, fear and happiness also varied significantly across segments. Regression analyses indicated that measures of pain could be predicted from measures of specific emotions.CONCLUSIONS: Emotion is an essential component of the acute phasic pain experienced during venepuncture. Although the occurrence of specific emotions varied as a function of pain, objective behavioural indexes and subjective behavioural ratings of pain were predicted by different emotional components than patients′ self‐reports.

Pain management in children.

Children experience pain differently than do adults. Adults experience a needle as a brief, uncomfortable, inconvenience; while children regard it as the epitome of all the evil of their disease (1). The emotional component of pain is very strong—a child may “feel” the absence of visitors or the missed class activity to be much more painful than the traction and broken leg in the hospital. Children with cancer have stated that they would rather die than receive another needle.

SPECT regional cerebral blood flow alterations in naltrexone-precipitated withdrawal from buprenorphine

The effects of naltrexone-precipitated withdrawal from buprenorphine on behavior and regional cerebral blood flow (rCBF) were studied in 11 opiate-dependent patients. Patients initially received buprenorphine, 2 mg sublingually, every day for 7 days. They were then challenged sequentially with placebo and naltrexone, 25 mg orally, before single photon emission computed tomography with technetium- 99m-d,l-hexamethyl-propylene amine oxime as tracer. Behavioral ratings of withdrawal severity were made before and after naltrexone/placebo administration. Naltrexone produced significantly greater signs and symptoms of opiate withdrawal than placebo. Analysis of variance revealed no significant regionally specific effect of naltrexone on rCBF ratios. Severity of withdrawal, however, showed a significant negative correlation with rCBF in the anterior cingulate cortex following naltrexone. These results are interesting as the anterior cingulate region has been implicated in the emotional component of pain and in opiate-induced analgesia.

SPECT regional cerebral blood flow alterations in naltrexone-precipitated withdrawal from buprenorphine

The effects of naltrexone-precipitated withdrawal from buprenorphine on behavior and regional cerebral blood flow (rCBF) were studied in 11 opiate-dependent patients. Patients initially received buprenorphine, 2 mg sublingually, every day for 7 days. They were then challenged sequentially with placebo and naltrexone, 25 mg orally, before single photon emission computed tomography with technetium-99m-d,l-hexamethyl-propylene amine oxime as tracer. Behavioral ratings of withdrawal severity were made before and after naltrexone/placebo administration. Naltrexone produced significantly greater signs and symptoms of opiate withdrawal than placebo. Analysis of variance revealed no significant regionally specific effect of naltrexone on rCBF ratios. Severity of withdrawal, however, showed a significant negative correlation with rCBF in the anterior cingulate cortex following naltrexone. These results are interesting as the anterior cingulate region has been implicated in the emotional component of pain and in opiate-induced analgesia.

The local cerebral metabolic effects of morphine in rats exposed to escapable footshock

The 2-deoxy- d-[1- 14C]glucose (2-DG) method was used to examine the effects of morphine sulfate (MS) on local cerebral metabolic rates for glucose (LCMR glu) in male F-344 rats required to turn a wheel manipulandum in order to escape from nociceptive footshock. Four groups of rats were studied: control-saline, control-MS, footshock-saline and footshock-MS. All animals were administered MS (4 mg/kg, s.c.) or saline 7 days, 3 days and 10 min prior to the start of the 2-DG experiment. In agreement with its well-known effect on the emotional component of pain, MS administered to rats exposed to footshock caused a significant decrease in LCMR glu compared to footshock-saline rats in limbic structures such as the diagonal band of Broca, lateral septum, bed nucleus of the stria terminalis, horizontal limb of the diagonal band, habenular complex and medial amygdala. Additionally, two components of the midline thalamus with extensive connections with the limbic system, the paraventricular and paratenial thalamic nuclei, were similarly affected by morphine. Footshock caused an overall increase in cerebral metabolism as 52 of 73 measured structures demonstrated increases in activity compared to saline control; however, statistically significant effects in specific structures were limited. These results identify limbic and midline thalamic structures important in morphine-induced analgesia and indicate that footshock tends to have a generalized stimulatory effect on LCMR glu.

Morphine decreases cerebral glucose utilization in limbic and forebrain regions while pain has no effect

Morphine alters affective states in humans and produces reinforcement in humans and animal subjects. Therefore, the present study was designed to determine whether morphine affected the functional activity in brain structures involved in emotion and motivation. Since opioid-induced analgesia largely reflects an influence on the emotional component of pain, the effect of pain on activity in these structures was also studied. Local rates of glucose utilization were measured by the 2-deoxy- D[1- 14C]glucose method in the brains of rats, that received morphine or saline, with or without a painful stimulus. Many rostral, and particularly diencephalic, nuclei showed decreased glucose utilization in morphine-treated rats, although caudal regions were mostly unaffected. There were dose-dependent decreases in glucose utilization with doses between 1 and 10 mg/kg morphine. However, nociceptive stimulation, with either formalin or tail-immersion, produced no significant effect on cerebral glucose utilization. The 2-deoxy- D-[1- 14C]-glucose technique, as used here, may lack adequate sensitivity to delineate areas of the brain mediating nociception in rats.

Acupuncture and emotion: the influence of acupuncture anesthesia on the sensory and emotional components of pain.

Objective indices (heart rate, perspiration quantity, finger plethysmograph curves, and facial expression) and subjective indices (sensory and emotional subject reports) were recorded for 25 young Chinese adults (16 men, 9 women) during and after the simultaneous application of a strong pain stimulus and either foot classical (alloneural points Tsusanli and Yanglingchuan) or hand classical (alloneural points Hegu and Neiguan) acupuncture. Both forms of acupuncture were equally effective, showing that stimulation of the same nerve is not essential for pain relief. Acupuncture assuaged the emotional, but not the sensory, response to the painful stimulation.

Tricyclic antidepressants in the treatment of cancer pain: a review.

The role of tricyclic antidepressants (TCAs) in the treatment of cancer pain is of growing interest. Various studies, all but one of them open, have suggested that TCAs are effective and safe in the treatment of pain caused by different types of cancer. The mechanisms of action by which TCAs decrease the pain perception are not fully clear. However, there are two main hypotheses. The first suggests that the drugs act primarily on the emotional component of pain, thus breaking the vicious circle of the perception of pain; the second suggests that the TCAs themselves have a specific analgesic action linked to a direct activity on the structures of the CNS. Further clinical studies, and in particular double-blind studies, are clearly necessary to provide more convincing and definitive results.

Psychological aspects of components of pain.

The present study investigated the inhibitory effects of acupuncture on the separate sensory and emotional components of pain and their relation to each other. Electro-acupuncture as practiced in China was applied to the same nerve used for initiating pain, and the responses of 9 adult volunteers (5 males, 4 females) were assessed. The results indicate that (a) pain involves at least two related but different components (the sensory component and the emotional component) and (b) electro-acupuncture has a stronger inhibitory effect on the emotional component of pain. The findings provide a new outlook for the improvement of the clinical effects of acupuncture and for further study of the pain mechanism.