Skin surface lipid differences in sensitive skin caused by psychological stress and distinguished by support vector machine.

BACKGROUND: Sensitive skin refers to skin that tends to be highly responsive to stimuli such as physical, chemical, and psychological. Psychological factors play an important role in the pathology of sensitive skin. OBJECTIVE: This study investigated lipid difference between sensitive skin caused by psychological stress and normal skin, followed by construction of a support vector machine (SVM). METHODS: A noninvasive method was used to collect lipid samples from the skin surface. Ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-Q-TOF-MS) technique and partial least squares-discriminant analysis (PLS-DA) was used to screen for differential lipids. A correlation analysis was performed on differential lipids, and a support vector model was established based on the differential lipids. RESULTS: Twelve differential lipids were obtained, and the most differentiating species were triacylglycerols (TGs), followed by monounsaturated fatty acids (MUFAs), saturated fatty acids (SFAs), diacylglycerols (DGs), and 6-hydroxysphingosine levels. Triglyceride, SFA, and MUFA species showed a high correlation, and the support vector machine (SVM) differentiation model based on differential lipids had a 100% accuracy rate. CONCLUSION: Psychological stress may cause damage to the permeability and antimicrobial barriers of the skin, thereby resulting in sensitive skin. Differentiation models based on SVMs have good prospects for distinguishing sensitive skin caused by psychological stress.

Validation of the French version of the Burn Specific Health Scale-Brief (BSHS-B) questionnaire.

INTRODUCTION: The Burn Specific Health Scale-Brief questionnaire is a widely validated tool for estimating the health related quality of life and for assessing the best multidisciplinary management of burn patients. The aim of this study was to translate the BSHS-B into French and to investigate its reliability and validity. METHODS: According to the procedure proposed by the Scientific Advisory Committee of the Medical Outcomes Trust, the Burn Specific Health Scale-Brief (BSHS-B) was translated from the English version into French. In order to test the reliability of the French version of the BSHS-B, 53 burn patients French speakers completed the BSHS-B and SF-36 questionnaires from two to four years after burn. Ten of them have been re-tested at 6 months after the first evaluation. To evaluate clinical utility of the BSHS-F, internal consistency, construct validity (using SF-36) and stability in time were assessed using Cronbach's alpha statistic, Spearman rank test, and intra-class correlation coefficient respectively. RESULTS: The French version of the BSHS-B Cronbach's alpha coefficient was 0.93 and was >0.80 for all the sub-domains. French version of the BSHS-B and the SF-36 were positively correlated, all the associations were statistically significant (p<0.01). Intra-class correlation coefficients for test-retest ranged between 0.95 and 0.99 for the sub-domains. The intra-class correlation coefficient (ICC) for the total score was 0.98. CONCLUSION: The French version of the BSHS-B shows a robust rate of internal consistency, construct validity and stability in time, supporting its application in routine clinical practice as well as in international studies.

Addition of posttraumatic stress and sensory hypersensitivity more accurately estimates disability and pain than fear avoidance measures alone after whiplash injury.

The fear avoidance model (FAM) has been proposed to explain the development of chronic disability in a variety of conditions including whiplash-associated disorders (WADs). The FAM does not account for symptoms of posttraumatic stress and sensory hypersensitivity, which are associated with poor recovery from whiplash injury. The aim of this study was to explore a model for the maintenance of pain and related disability in people with WAD including symptoms of PTSD, sensory hypersensitivity, and FAM components. The relationship between individual components in the model and disability and how these relationships changed over the first 12 weeks after injury were investigated. We performed a longitudinal study of 103 (74 female) patients with WAD. Measures of pain intensity, cold and mechanical pain thresholds, symptoms of posttraumatic stress, pain catastrophising, kinesiophobia, and fear of cervical spine movement were collected within 6 weeks of injury and at 12 weeks after injury. Mixed-model analysis using Neck Disability Index (NDI) scores and average 24-hour pain intensity as the dependent variables revealed that overall model fit was greatest when measures of fear of movement, posttraumatic stress, and sensory hypersensitivity were included. The interactive effects of time with catastrophising and time with fear of activity of the cervical spine were also included in the best model for disability. These results provide preliminary support for the addition of neurobiological and stress system components to the FAM to explain poor outcome in patients with WAD.

Irritable bowel syndrome and visceral hypersensitivity : risk factors and pathophysiological mechanisms.

Irritable bowel syndrome (IBS) is a common functional gastro-intestinal disorder, characterized by abdominal pain and altered intestinal motility. Visceral hypersensitivity is an important hallmark feature of IBS and is believed to underlie abdominal pain in patients with IBS. The two main risk factors associated with the development of IBS are gastrointestinal inflammation and psychological distress. On a peripheral level, visceral sensitivity seems to be modulated by several mechanisms. Immune cells in the mucosal wall, such as mast cells, and enterochromaffin cells may sensitize afferent nerves by release of their mediators. Furthermore, increased mucosal permeability, altered intestinal microflora and dietary habits may contribute to this feature. On a central level, an increased prevalence of psychiatric comorbidities is demonstrated in IBS patients, alongside alterations in the hormonal brain-gut axis, increased vigilance towards intestinal stimuli and functional and structural changes in the brain. The pathogenesis of IBS is complicated and multifactorial and the treatment remains clinically challenging. Dietary measures and symptomatic control are the cornerstones for IBS treatment and may be sufficient for patients experiencing mild symptoms, alongside education, reassurance and an effective therapeutic physician-patient relationship. New pharmacological therapies are aimed at interfering with mediator release and/or blockade of the relevant receptors within the gut wall, while modulation of the intestinal flora and diet may also be of therapeutic benefit. Tricyclic anti-depressants and serotonin reuptake inhibitors act both on a central and peripheral level by modulating pain signalling pathways.

Olfactory processing in adults with autism spectrum disorders.

BACKGROUND: As evidenced in the DSM-V, autism spectrum disorders (ASD) are often characterized by atypical sensory behavior (hyper- or hypo-reactivity), but very few studies have evaluated olfactory abilities in individuals with ASD. METHODS: Fifteen adults with ASD and 15 typically developing participants underwent olfactory tests focused on superficial (suprathreshold detection task), perceptual (intensity and pleasantness judgment tasks), and semantic (identification task) odor processing. RESULTS: In terms of suprathreshold detection performance, decreased discrimination scores and increased bias scores were observed in the ASD group. Furthermore, the participants with ASD exhibited increased intensity judgment scores and impaired scores for pleasantness judgments of unpleasant odorants. Decreased identification performance was also observed in the participants with ASD compared with the typically developing participants. This decrease was partly attributed to a higher number of near misses (a category close to veridical labels) among the participants with ASD than was observed among the typically developing participants. CONCLUSIONS: The changes in discrimination and bias scores were the result of a high number of false alarms among the participants with ASD, which suggests the adoption of a liberal attitude in their responses. Atypical intensity and pleasantness ratings were associated with hyperresponsiveness and flattened emotional reactions, respectively, which are typical of participants with ASD. The high number of near misses as non-veridical labels suggested that categorical processing is functional in individuals with ASD and could be explained by attention-deficit/hyperactivity disorder. These findings are discussed in terms of dysfunction of the olfactory system.

Persistent neuropathic pain influences persistence behavior in rats.

AIMS: To determine whether self-regulation can be studied successfully in a rodent model and whether persistent facial pain influences self-regulatory behavior. METHODS: Thirty male Sprague-Dawley rats, divided into two groups, (1) chronic constriction injury of the infraorbital nerve (CCI-ION) and (2) naïve, were used in a two-part behavioral paradigm of self-regulation. This paradigm consisted of both a cued go/no-go task (part one) and a persistence trial (part two). All animals were acclimated and trained for a period of 4 weeks prior to the experimental manipulation and then tested for a total of 5 weeks following experimental manipulation. Results were analyzed with t tests, one-way analysis of variance, and two-way, repeated measures analysis of variance. RESULTS: CCI-ION surgery induced significant mechanical hypersensitivity of the ipsilateral whisker pad that began 3 weeks postsurgery and persisted through the duration of the experiment (P < .001). At weeks 4 and 5 post-experimental manipulation, naïve animals demonstrated a significant decrease in lever presses during the persistence task (P < .05) compared to baseline, whereas CCI-ION animals did not (P = .55). CONCLUSION: These results suggest that persistent pain influences behavioral regulation and that animals experiencing persistent pain may have difficulty adapting to environmental demands.

Disability and health after replantation or revascularisation in the upper extremity in a population in southern Sweden - a retrospective long time follow up.

BACKGROUND: Replantation in the upper extremity is a well-established microsurgical procedure. Many have reported patients' satisfaction and functional measurements.The aim was to investigate the long time consequences as activity limitations in hand/arm, the general health and cold sensitivity after a replantation or revascularization in the upper extremity and to examine if sense of coherence (SOC) can be an indicator for rehabilitation focus. METHODS: Between 1994-2008, 326 patients needed replantation/revascularization in the upper extremity. 297 patients were followed up. Information was collected from the medical notes and by questionnaires [Quick-DASH (disability hand/arm), EuroQ-5D (general health), CISS (cold sensitivity) and SOC (sense of coherence)]. Severity of injury was classified with the modified Hand Injury Severity Score (MHISS). RESULTS: The patients [272 (84%) men and 54 (16%) women; median age 39 years (1-81 years)], where most injuries affected fingers (63%) and thumb (25%), commonly affecting the proximal phalanx (43%). The injuries were commonly related to saws (22%), machines (20%) and wood splints (20%). A direct anastomosis (30%) or vein grafts (70%) were used. The overall survival was 90%. 59% were classified as Major.Equal parts of the injuries took part during work and leisure, DASH scores at follow up were worse (p = 0.005) in the former. Twenty percent changed work and 10% retired early. Patients with early retirement were significantly older, had a more severe injury, worse disability, quality of life and functional outcome. Median DASH score was low [11.4 (0-88.6)] and correlated with severity of injury. Abnormal cold sensitivity (CISS > 50) was seen in 51/209 (24%) and they had a worse disability, quality of life, functional outcome and lower SOC. Patients with a low SOC had on the whole a worse outcome compared to patients with a high SOC and with significant differences in age, EQ-5D, Quick-DASH and CISS. CONCLUSIONS: A high MHISS, abnormal cold intolerance and a low SOC seems to be factors influencing the patients' outcome and might be relevant in the rehabilitation of the patients. Also, those who had to retire early had a worse disability, quality of life and functional outcome.

Multimodal physical therapy management of a 48-year-old female with post-stroke complex regional pain syndrome.

This case report describes a 48-year-old female who presented with complaints of right shoulder pain, hyperesthesias and swelling of the hand along with added symptoms of pain centralization following a cerebrovascular accident. On clinical evaluation, the patient satisfied the Budapest diagnostic criteria for Complex Regional Pain Syndrome (CRPS) type-1. Physical therapy management (1st three sessions) was initially focused on pain neurophysiology education with an aim to reduce kinesiophobia and reconceptualise her pain perception. The patient had an immediate significant improvement in her pain and functional status. Following this, pain modulation in the form of transcutaneous electrical nerve stimulation, kinesio tape application, "pain exposure" physical therapy and exercise therapy was carried out for a period of 7 weeks. The patient had complete resolution of her symptoms which was maintained at a six-month follow-up.

Heightened sensitivity to somatosensory stimuli in anorexia nervosa: an exploratory study with the SASTCA scale.

OBJECTIVES: To analyse the presence of heightened sensory sensitivity in patients with anorexia nervosa, which seems similar but not identical to that described in patients with unexplained somatic symptoms or body dysmorphic disorder. METHODS: We developed a sensory sensitivity scale in eating disorders (SASTCA), which measures the intensity of the response to specific somatosensory stimuli. The scale was completed by 48 patients with anorexia and a control group of 31 participants matched in age, sex and social and educational level. The results were compared with those obtained with the Barsky Somatosensory Amplification Scale (SSAS). RESULTS: The reliability (Cronbach's/alpha, 0.946; Guttman/ split-half, 0.936) and validity (ROC, 0.933) of the SASTCA scale are indicative of its high sensitivity and specificity. The anorexia group had a significantly higher mean score on the SASTCA scale than the control group (p<.001). Similarly, the patients with anorexia had a significantly higher mean value on the SSAS than the participants in the control group (p<.01), although the difference was less extreme. The 2 scales correlated positively (r=.634). DISCUSSION: These preliminary results suggest the presence in Anorexia of heightened sensory sensitivity which differs from the sensitivity of the control group. This sensitivity has a significant relationship with that described in patients with somatic complaints about health (SSD) or appearance (BDD). Could this heightened sensory sensitivity help us to explain the process of forming the distorted body self-concept (I'm fat, sick, ugly) in all these patients? Once its presence has been confirmed in other patients with anorexia, their relatives and other patients with somatic disorders this heightened sensitivity could constitute the somatic endophenotype of anorexia?

Objetivo: destacar la presencia de una sensibilidad extrema hacia estímulos externos e internos (Amplificación Somatosensorial) en pacientes con Anorexia, similar pero no idéntica, a la descrita en pacientes con unexple somatic symtoms. Método: Se ha elaborado una escala de Amplificación Somatosensorial para Trastornos de la Conducta Alimentaria, (SASTCA), que mide la intensidad de la respuesta hacia estímulos somatosensoriales específicos. La escala ha sido cumplimentada por un grupo de 48 pacientes anoréxicas y un grupo control de 31 sujetos emparejados en edad, sexo y nivel socioeducativo. Los resultados se han comparado con los obtenidos en la escala SSAS de Barsky. Resultados: La Fiabilidad (Alfa de Cronbach 0,946; dos mitades de Guttman 0,936) y la Validez (ROC, 0,933), son indicativas de elevada sensibilidad y especificidad de la escala SASTCA. El grupo de pacientes presenta una media 58,73 12,38, significativamente superior al grupo control 37,81 7,47, (=0,001). Las pacientes presentan en la escala SSAS una media 31,21 6,68 significativamente superior al grupo control 26,58 5,49 (=0,01), aunque la diferencia es menos extremada. Ambas escalas correlacionan positivamente. 0,634 Conclusiones: Los resultados sugieren la presencia en AN. de una sensibilidad extrema hacia estímulos somatosensoriales. ¿Podria esta elevada sensibilidad sensorial ayudarnos a explicar el proceso de formación del auto-concepto distorsionado ("gordo, enfermo, feo") de estos pacientes? De confirmar su presencia en otras muestras de pacientes con anorexia, en sus familiares y en diferentes pacientes somatomorfos o TCA, esta elevada sensibilidad podría considerarse el endofenotipo somatomorfo del trastorno anoréxico.

Emotion regulation difficulties in anorexia nervosa: Relationship to self-perceived sensory sensitivity.

Changes in sensation (e.g., prickly skin) are crucial constituents of emotional experience, and the intensity of perceived changes has been linked to emotional intensity and dysregulation. The current study examined the relationship between sensory sensitivity and emotion regulation among adults with anorexia nervosa (AN), a disorder characterised by disturbance in the experience of the body. Twenty-one individuals with AN, 20 individuals with AN who were weight-restored, and 23 typical controls completed self-report measures of sensory sensitivity and emotion regulation. AN participants reported heightened sensory sensitivity and greater difficulty regulating emotions relative to controls. Self-perceived sensory sensitivity was associated with greater emotion dysregulation. Weight-restored AN participants reported greater ability to regulate emotions than their currently underweight counterparts, despite heightened sensitivity. Findings suggest that hypersensitivity may be a persisting feature in AN, and that weight restoration may involve improved ability to cope with sensation.

Sensory over-responsivity, psychopathology, and family impairment in school-aged children.

OBJECTIVE: To establish the diagnostic validity of sensory overresponsivity (SOR), there is a need to document rates of SOR and the co-occurrence of SOR with other psychiatric disorders. Although this was not a diagnostic study of SOR, this study was designed to investigate rates of elevated SOR symptoms and associations between elevated SOR symptoms, psychiatric disorder status, and family impairment. METHOD: From a larger birth cohort followed from infancy to school age, 338 children aged 7 to 10 years (51% boys, 49% girls) and their parents participated in an intensive assessment. Parents were interviewed with the Diagnostic Interview Schedule for Children (DISC) and completed the SensOR inventory and the Family Life Impairment Scale. RESULTS: Approximately one-fifth (21.2%) of children had elevated SOR symptoms. One-fourth (24.3%) of those with an elevated SOR score met criteria for a DSM-IV diagnosis, and 25.4% of children with a DSM-IV diagnosis had an elevated SOR score. Parents of children with elevated SOR alone reported a similar number of restrictions in family life as parents of those with an internalizing and/or externalizing diagnosis. SOR predicted concurrent family impairment above and beyond DSM diagnostic status and socio-demographic risk. CONCLUSIONS: Elevated SOR occurs in the absence of other psychiatric conditions and is associated with impairment in family life. Services for children with comorbid elevated SOR and an externalizing disorder are needed to address the extremely high level of family impairment reported.

An increased response to experimental muscle pain is related to psychological status in women with chronic non-traumatic neck-shoulder pain.

BACKGROUND: Neck-shoulder pain conditions, e.g., chronic trapezius myalgia, have been associated with sensory disturbances such as increased sensitivity to experimentally induced pain. This study investigated pain sensitivity in terms of bilateral pressure pain thresholds over the trapezius and tibialis anterior muscles and pain responses after a unilateral hypertonic saline infusion into the right legs tibialis anterior muscle and related those parameters to intensity and area size of the clinical pain and to psychological factors (sleeping problems, depression, anxiety, catastrophizing and fear-avoidance). METHODS: Nineteen women with chronic non-traumatic neck-shoulder pain but without simultaneous anatomically widespread clinical pain (NSP) and 30 age-matched pain-free female control subjects (CON) participated in the study. RESULTS: NSP had lower pressure pain thresholds over the trapezius and over the tibialis anterior muscles and experienced hypertonic saline-evoked pain in the tibialis anterior muscle to be significantly more intense and locally more widespread than CON. More intense symptoms of anxiety and depression together with a higher disability level were associated with increased pain responses to experimental pain induction and a larger area size of the clinical neck-shoulder pain at its worst. CONCLUSION: These results indicate that central mechanisms e.g., central sensitization and altered descending control, are involved in chronic neck-shoulder pain since sensory hypersensitivity was found in areas distant to the site of clinical pain. Psychological status was found to interact with the perception, intensity, duration and distribution of induced pain (hypertonic saline) together with the spreading of clinical pain. The duration and intensity of pain correlated negatively with pressure pain thresholds.

Clinical and personality features of allodynic migraine.

Cutaneous allodynia (CA) is a frequent complaint during migraine attacks, recently associated with migraine transformation as well as psychiatric comorbidities. The aim of our study was to define the clinical features of allodynic migraineurs, in particular, the relationship between CA and personality profile. Between October 2008 and December 2009, 410 migraineurs admitted for the first time to our Headache Center underwent Allodynia Symptom Checklist, MIgraine DIsability Assessment Scale (MIDAS) and psychometric tests [Tridimensional Personality Questionnaire (TPQ), Toronto Alexithymia Scale, State and Trait Anxiety Inventory (STAI Y 1-2), and Beck Depression Inventory (BDI)]. Allodynia was present in 63% of cases, mostly in females. In CA patients, an association with female sex, chronic migraine, higher values of MIDAS, BDI, harm avoidance (HA, a TPQ dimension) and STAI Y-2 was found. Interestingly, CA appears to be associated with depression and a particular personality profile characterized by higher values of HA, suggesting an involvement of the serotonergic system in the development of CA in migraine. In conclusion, CA is associated with progression of migraine and it could be a marker of psychiatric comorbidities, in particular, depression and anxious trait.

The CatWalk method: assessment of mechanical allodynia in experimental chronic pain.

The CatWalk gait analysis system has recently been suggested as a rapid and objective alternative method over the von Frey test to assess mechanical allodynia in chronic neuropathic pain models. Our results demonstrate that no correlation exists between the development of mechanical allodynia and changes in CatWalk-gait parameters in a chronic inflammatory pain model. Hence, the use of the CatWalk in assessment of experimental chronic pain is discussed.

Differential implication of proinflammatory cytokine interleukin-6 in the development of cephalic versus extracephalic neuropathic pain in rats.

Responses resulting from injury to the trigeminal nerve exhibit differences compared with those caused by lesion of other peripheral nerves. With the aim of elucidating the physiopathological mechanisms underlying cephalic versus extracephalic neuropathic pain, we determined the time course expression of proinflammatory cytokines interleukin-6 (IL-6) and IL-1beta, neuronal injury (ATF3), macrophage/microglial (OX-42), and satellite cells/astrocyte (GFAP) markers in central and ganglion tissues in rats that underwent unilateral chronic constriction injury (CCI) to either infraorbital nerve (IoN) (cephalic area) or sciatic nerve (SN) (extracephalic area). Whereas CCI induced microglial activation in both models, we observed a concomitant upregulation of IL-6 and ATF3 in the ipsilateral dorsal horn of the lumbar cord in SN-CCI rats but not in the ipsilateral spinal nucleus of the trigeminal nerve (Sp5c) in IoN-CCI rats. Preemptive treatment with minocycline (daily administration of 20 mg/kg, i.p., for 2 weeks) partially prevented pain behavior and microglial activation in SN-CCI rats but was ineffective in IoN-CCI rats. We show that IL-6 can upregulate OX-42 and ATF3 expression in cultured microglia and neurons from spinal cord, respectively, as well as in the dorsal horn after acute intrathecal administration of the cytokine. We propose that IL-6 could be one of the promoters of the signaling cascade leading to abnormal pain behavior in SN-CCI but not IoN-CCI rats. Our data further support the idea that different pathophysiological mechanisms contribute to the development of cephalic versus extracephalic neuropathic pain.

Illusion of pain: pre-existing knowledge determines brain activation of 'imagined allodynia'.

UNLABELLED: Allodynia means that innocuous tactile stimulation is felt as pain. Accordingly, cerebral activations during allodynia or touch should markedly differ. The aim of this study was to investigate whether the imagination of allodynia affects brain processing of touch in healthy subjects. Seventeen healthy subjects divided into 2 subgroups were investigated: The first group (n = 7) was familiar with allodynia, based on previous pain studies, whereas the second group (n = 10) had never knowingly experienced allodynia. Using functional magnetic resonance imaging, 2 experimental conditions were investigated. In one condition the subjects were simply touched at their left hand, whereas during the other condition they were asked to imagine pain (allodynia) during tactile stimulation of the right hand and to estimate the imagined pain on a numeric rating scale. Data processing and analysis were performed with the use of SPM5. The group analysis of all subjects revealed that tactile stimulation activated contralateral somatosensory cortices (S1 [primary] and S2 [secondary]), but the imagination of allodynia led to an additional activation of anterior cingulate cortex and bilateral activation of S2, insular cortex, and prefrontal cortices. Subgroup analysis using rating-weighted predictors revealed activation of the contralateral thalamus, anterior cingulate cortex, and amygdala and a bilateral activation of S1, S2, and insular cortex and prefrontal cortices in allodynia-experienced subjects. In contrast, allodynia-inexperienced subjects only activated contralateral S1 and bilateral S2. Just the imagination that touch is painful is able to partly activate the central pain system, but only when the subject has previous experience of this. According to our results, the medial pain system is involved in the encoding of imagined allodynia. PERSPECTIVE: This article reports that pain experience is able to alter central processing of sensory stimuli. Pain knowledge appears to be able to shift "normal" tactile processing to a different quality, resulting in modified brain activity. Therefore, our study may contribute to the current understanding of human pain and will promote future research on this field.

[An analysis on SCL-90 of pharyngeal paraesthesia].

OBJECTIVE: To explore the mental health of the patients who suffered from pharyngeal paraesthesia, and investigate the effect of mental factors during the happening, development, therapy and turnover of the disease. METHOD: The Symptom Checklist 90 (SCL-90) was used to collect information,and all the data was dealed with SPSS 12.0. RESULT: (1) The total score of SCL-90 of pharyngeal paraesthesia was higher than the norm, and the score of positive items and average score of positive symptom were both significantly higher than the norm; (2) There was no differences between pharyngeal paraesthesia and the norm in terror factor while significant differences in the others; (3) There was no difference between male and female patients who suffered from pharyngeal paraesthesia. CONCLUSION: Compared with the normal, patients who suffered from pharyngeal paraesthesia had obvious mental symptoms, such as somatization, anxiety, depression et al.

Upregulation of substance P in low-threshold myelinated afferents is not required for tactile allodynia in the chronic constriction injury and spinal nerve ligation models.

It has been proposed that substance P and calcitonin gene-related peptide (CGRP) are upregulated in low-threshold myelinated primary afferents after certain types of nerve injury, and that release of substance P from these afferents contributes to the resulting tactile allodynia. To test this hypothesis, we looked for neuropeptides in Abeta primary afferent terminals in the ipsilateral gracile nucleus and spinal dorsal horn in three nerve injury models: sciatic nerve transection (SNT), spinal nerve ligation (SNL), and chronic constriction injury (CCI). We also looked for evidence of neurokinin 1 (NK1) receptor internalization in the dorsal horn after electrical stimulation of Abeta afferents. We found no evidence of either substance P or CGRP expression in injured Abeta terminals in the spinal cord in any of the models. Although substance P was not detected in terminals of injured afferents in the gracile nucleus, CGRP was expressed in between 32 and 68% of these terminals, with a significantly higher proportion in the SNL and CCI models, compared with SNT. In addition, we did not detect any Abeta-evoked NK1 receptor internalization in neurons from laminas I, III, or IV of the dorsal horn in the CCI or SNL models. These results do not support the proposal that substance P is present at significant levels in the terminals of injured Abeta primary afferents in neuropathic models. They also suggest that any release of substance P from injured Abeta afferents is unlikely to activate NK1 receptors in the dorsal horn or contribute to neuropathic pain.