Nociceptive Experience Research Articles

Nonpharmacological treatment for coping with pain

Pain is one of the most common reasons for consultation and one of the most difficult tasks to handle for doctors. If it is chronic, the frequency of disorders increases associates that we cannot exclude from the treatment, and further complicates your treatment. The Asociation International Association for the Study of Pain (IAPS)1 defines the pain as "a sensory and emotional experience unpleasant associated with actual or potential tissue damage, or described in terms of such damage". So the pain is not only a nociceptive experience, but also involves emotional and subjective components, considering that It can even occur without a somatic cause justify. Its nature is complex, including factors biological and others such as subjective experience, education and emotion. Therefore pain is a personal, multidimensional problem, unique experience and non-transferable of the person who suffers it. Being a pharmacological and non-pharmacological approach is necessary for its management.

Non pharmacologic interventions for pain associated to venipuncture in children: a literature review

Venipuncture is one of the most common painful procedures performed on children. Pain prevention and control are essential in childhood, because the earlier is the nociceptive experience, the more it affects the response to subsequent painful events. To analyse the literature on non-pharmacological methods of pain management in children undergoing venipuncture. The review was carried out between May and July 2019 by consulting the PubMed and Cochrane Database, combining Mesh terms and free text. The references reported in the articles found in the first part of the research were also analyzed, to identify further relevant studies. A total of 20 articles were included in this review (8 randomized clinical trials, 10 systematic reviews, 1 meta-analysis and 1 pilot study), on a total population of almost 20,086 children aged 1-18 years. The settings considered by the studies were pediatric wards, pediatric outpatient, and Emergency Department. Non-pharmacological interventions can be classified in 4 categories: supportive or environmental therapies; physical therapies; cognitive-behavioral therapies; and non-nutritive suction for newborns and infants. The strength of evidence ranged from high to low or extremely low. Most non-pharmacological methods are simple, cheap, easily acquired, and do not need excessive application time. They allow pain control and support the comfort and cooperation of children undergoing venipuncture, alone or combined to pharmacological treatment.

A key developmental step for preterm babies: achievement of full oral feeding

Aims: To investigate timing of oral feeding (OF) introduction and full oral feeding (FOF) achievement in preterm infants and to explore factors associated with feeding progression.Methods: Retrospective review of 100 medical records of preterms ≤32 weeks of gestation (GA) without major complications. Outcome measures were timing of OF introduction, transition time from nasogastric tube to FOF and FOF achievement. Variables such as sex, twins, GA, birthweight, respiratory supports used and duration of tube feeding, were also considered.Results: Post menstrual age (PMA) for OF introduction was 33.6 ± 1.1 weeks. FOF was achieved at 35.1 ± 1.5 weeks. PMA at OF introduction and PMA at FOF correlated with: birthweight (p = .0001, p = .001); duration of respiratory supports (p = 0.01, p = .0001); PMA at which respiratory supports were stopped (p = .0001, p = .0001); age of introduction of gavage (p = .0001, p = .003) and time of utilization of tube feeding (p = .02, p = .0001). Transition time was 1.5 ± 8.5 days. PMA at OF introduction significantly influenced PMA at FOF (p = .0001, r = .61). OF introduction, transition time and FOF were correlated with duration of hospitalization (p = .004, p = .0001, p = .008).Conclusions: The achievement of feeding skills is confirmed to affect length of hospitalization, but the earlier you introduce OF, the earlier you reach FOF, so introduction should be anticipated. There is a clear trend to favor higher birthweight classes in FOF achievement. Feeding tube placement and need for respiratory supports may represent a nociceptive experience delaying feeding skills' achievement. This highlights the importance of prospective studies investigating the role of preventative interventions.

BEEP-Bodily and Emotional Perception of Pain. A Questionnaire to Measure Reaction to Pain in Chronic Pain Disorders.

Background: The assessment of pain and its impact on quality of life is central to the evaluation of chronic pain syndromes. However, most available tools focus on the nociceptive experience of pain, and at best only consider the occurrence of anxious, depressive, or cognitive problems. Here is a new questionnaire aimed at measuring the multifaceted impact of pain in chronic pain syndromes, the Bodily and Emotional pErception of Pain (BEEP).Methods: All consecutive patients who accessed a center for the treatment of pain were invited to take part in the study. The sample included 222 participants (51 with fibromyalgia, 84 with low back pain; 87 with other chronic pain syndromes). Women were 77% of the sample, the mean age was 61 ± 15. Participants completed the BEEP, the Patient Health Questionnaire-9 (PHQ-9), and the Mood Disorder Questionnaire (MDQ).Results: Reliability was good for all questionnaires. The expected three dimensions of the BEEP were confirmed by confirmatory factor analysis, and a bifactor model with three orthogonal factors showed a good fit as well. Participants diagnosed with fibromyalgia showed higher scores on the BEEP than the participants who had been diagnosed with low back pain or other chronic pain syndromes. The prevalence of probable cases of major depression and bipolar disorder in the sample was higher than expected for non-clinical samples. Levels of depression, as measured by the PHQ-9, were associated with the three dimensions of the BEEP and with the intensity of pain.Conclusions: The BEEP is a promising measure of the impact of pain in daily life and differentiates fibromyalgia from other chronic pain syndromes. The BEEP may be helpful to evaluate the patient's response to the treatment over time and may favor the identification of unmet needs in patients' personal, social, and daily functioning.

Repeated neonatal needle-prick stimulation increases inflammatory mechanical hypersensitivity in adult rats

Background and aimsNewborn infants are vulnerable to procedural stress and pain exposure on the first weeks of life that represents a critical period for the development of nociceptive, sensory, emotional, and social functions. We evaluated the nociceptive behavior of adult male and female rats that were submitted to nociceptive experience in the neonatal period and the maternal behavior in the postnatal period. MethodsThe animals were submitted to repetitive needle pricking from the second to the fifteenth postnatal day (PND 2–15). Maternal behavior and litter weight were evaluated during this period. Mechanical sensitivity to pain was assessed in offsprings during the adulthood by exposing them to inflammatory stimuli, including formalin test or the Freund’s complete adjuvant (CFA) injection followed by the electronic von Frey test at 0, 3, 6 and 24 h later. ResultsMaternal behavior and litter weight were not altered by pinprick stimuli during PND 2–15. Additionally, pinprick stimulation reduced the paw withdrawal threshold in CFA-injected animals compared to control. In the formalin test, there was a difference between the genders. Female rats are statically more sensitive to formalin stimulation and showed an increased licking time in both the first and second phases and increased number of flinches in second phase. ConclusionsExperiencing early life repetitive pain exposure increased inflammatory pain sensitivity in adult offspring rats and female rats are more sensitive to chemical stimulation. ImplicationsFuture investigations of the mechanisms involved in this effect may contribute to the improvement of the understanding of inflammatory pain sensitivity differences.

79. Laser-evoked potentials in non-organic origin pain

Laser-evoked potentials (LEPs) represent the most reliable method to diagnose and follow over time painful small fiber neuropathies. Here, we investigated LEPs in patients with pain of non-organic origin. LEPs were recorded with a Nd:Yag Laser in 4 subjects with pain of non-organic origin, stimulating the dorsum of the hand and the dorsum of the foot bilaterally. We measured the perceptive threshold, latency and amplitude of N1 wave and N2/P2 complex within the painful territory and at contralateral site. We then compared these responses with those obtained in five sex- and age-matched healthy volunterees. We observed a significant increase in amplitude of N1 (p = 0.023) and N2/P2 (p = 0.015) responses in the painful territory compared both with contralateral side and healthy subjects. In patients, an additional positive wave at about 300 ms was detected only when the painfulside was stimulated; this response became more pronounced during stimulus expectation. Our data suggest that increased laser responses characterize subjects with pain of non-organic origin and likely reflect a strong emotional component in the nociceptive experience; the P3 component is probably related to cognitive modulation and anticipation phenomena, thus suggesting a functional (psychogenic) origin of the pain.

Emotional reactions to pain predict psychological distress in adult patients with Sickle Cell Disease (SCD).

Differentiating somatic from emotional influences on the experience of chronic pain has been of interest to clinicians and researchers for many years. Although prior research has not well specified these pathways at the anatomical level, some evidence, both theoretical and empirical, suggest that emotional reactions influence the experience of disease and non-disease-related pains. Other studies suggest that treatments directed at negative emotional responses reduce suffering associated with pain. The current study was conducted to explore the influence of emotional reactions to pain as a predictor of psychological distress in a sample of adult Blacks with Sickle Cell Disease (SCD). Using cross-sectional survey data, we evaluated whether negative emotional reactions to the experience of pain were predictive of psychological distress after controlling for the somatic dimension of pain and age in n = 67 Black patients with Sickle Cell Disease (SCD). Results showed that greater negative emotion associated with pain predicted Somatization (p < .01), Anxiety (p < .05), Phobic Anxiety (p < .05), and Psychoticism (p < .05). Increased negative emotion associated with pain was also predictive of the General Symptoms Index (p < .05) and the Positive Symptoms Total from the SCL-90-R (p < .01). We believe the current study demonstrates that negative emotional reactions to the experience of pain in adults with SCD are predictive of psychological distress above and beyond the influences of age and the direct nociceptive experience. We also believe these data to be valuable in conceptualizing the allocation of treatment resources toward a proactive approach with early identification of patients who are responding poorly for the purpose of potentially reducing later psychopathology. A deeper understanding of the ways that subpopulations cope with chronic disease-related pain may produce models that can be ultimately generalized to the consumers of the majority of healthcare resources.

Pain Perception and Anaesthesia in Research Frogs

Frogs possess pain receptors and pathways that support processing and perception of noxious stimuli however the level of organization is less well structured compared to mammals. It was long believed that the experience of pain was limited to 'higher' phylums of the animal kingdom. However, it is now commonly accepted that amphibians possess neuro-anatomical pathways conductive of a complete nociceptive experience. Xenopus laevis frogs have been one of the most popular aquatic research models for developmental studies and genetic research. These frogs have been extensively use in research for their eggs, that can be collected following hormonal stimulation either naturally or by surgical intervention. Many anaesthetics have been used in amphibians such as bath solutions of MS-222, benzocaine and eugenol as well as systemic injections of ketamine or tiletamine, barbiturates, propofol and gas administrations of methoxyflurane, halothane and isoflurane. Most of these anaesthetic drugs produce variability in depth and duration of anaesthesia. MS-222 appears to be one of the most reliable anaesthetics. This review will focus on the evidence of pain perception in frogs and will compare the effectiveness and limitations of different anaesthetics used in Xenopus leavis frogs.

Revisiting the Cartesian model of pain

In modern medicine, the Cartesian or nociceptive concept of chronic pain has been replaced with the biopsychosocial model in both theory and practice. This paper presents an argument along with observations in favor of chronic pain as a pure nociceptive experience separate from suffering and outlines theoretical and practical solutions to improve the diagnosis and treatment of patients who experience chronic pain. Theoretical solutions include increasing inhibitory descending neurotransmitters using monoamine oxidase inhibitors of subtype A in combination with dextroamphetamine, increasing beta endorphin through enzymology and/or ultrasound stimulation of the periaqueductal gray, developing long duration opioid analgesics using spin label probes of morphine and morphine analogs and destructive interference of nociceptive action potentials by eddy currents generated by a variable magnetic field. Practical solutions include prolonging local anesthetic blockade of small pain fibers with patient administered local anesthetic storage devices and abandonment of the multidisciplinary pain clinic.

Hippocampal theta state in relation to formalin nociception

In the present study using extracellular electrophysiological recording techniques, we explored the temporal characteristics of hippocampal theta activation in relation to formalin nociception. Results indicate that, compared to hind paw injection of saline, formalin injection in behaving rat evoked biphasic increase in duration of dorsal CA1 theta. Such an increase broadly paralleled animal biphasic behavioral activation, especially lick and moment-to-moment agitated behaviors. Correspondingly, theta-modulated cell firing was observed following formalin injection in anesthetized rat. The formalin-induced theta activation in behaving rat was most marked during peak of theta activation in the 2nd theta state (11–40 min post-injection) comprising 73% of the time in the 5 min block. An increase in theta peak frequency was also observed with respect to pre-injection control. However, the peak of theta in the 2nd theta state mostly preceded the peak of lick and flinch of the affected paw. In the 41–60 min, following formalin injection while the animals displayed robust nociceptive flinching and lifting, the theta activity approached control levels. Furthermore, the theta peak frequency at peak of theta was higher than the corresponding values of sustained theta observed in correlation with the nociceptive behaviors; in contrast, high frequency theta rhythm was observed during formalin-induced other moment-to-moment agitated behaviors. These findings favor the notion that in the formalin model the theta state of the hippocampus reflects a neural drive that is dissociated from the duration of nociceptive experience and is not selective to the typical nociceptive indices of lick, flinch, and lift of the injured paw.

Effects of inhibition of the GABAergic systems by picrotoxin on retention of a nociceptive experience in the rat, with special reference to the influence of cerebellar cortex output

Adult cerebellectomized and noncerebellectomized DA/HAN strain (pigmented) female rats were submitted to a one-trial passive avoidance conditioning procedure consisting in associating darkness with a nociceptive stimulus. Seven days later, they were tested again to assess the retention stage. The results demonstrate that in noncerebellectomized rats, picrotoxin, whatever the dose, administered prior to the retention test, does not significantly impair retrieval. On the contrary, when administered just prior to the initial conditioning, impairments of the initial single nociceptive experience were evident (the greater the picrotoxin dose, the greater the impairments). In animals that were cerebellectomized 1 week before the experiment, picrotoxin administered at a low dose before the initial experience elicited memory impairments that were similar to those induced in noncerebellectomized rats but that were greater than those elicited in cerebellectomized, nontreated animals. However, in cerebellectomized rats, picrotoxin administered at a low dose elicited memory impairments that were weaker than in noncerebellectomized animals injected with a high dose of the drug. Considering that a low dose of picrotoxin administered to cerebellectomized animals had effects that were similar to those of a high dose injected to noncerebellectomized rats, and given that it has previously been demonstrated that a cerebellectomy performed after a single nociceptive experience impairs its memory, it is tempting to suggest that the two different doses of the drug administered to cerebellectomized and noncerebellectomized rats have similar effects on memory. If such an interpretation is valid, the information would have to leave the cerebellar cortex to be stored for long.