Investigation of itch in Parkinson disease

Introduction: Sensory abnormalities (eg, pain) are common in Parkinson disease (PD) with a negative impact on quality of life. As itch is less studied in PD, and pain and itch partially share sensory pathways, we designed this study to identify the occurrence and pattern of spontaneous itch, and responsiveness to a surrogate itch model in PD. Methods: The study protocol was approved (N-20180079) and PD patients and their best matched controls were recruited. A questionnaire was used to collect general information on itch. Sensory alterations were determined by subjective ratings and mechanical sensitivity threshold before and after a standard histamine-dependent itch model on forearms. Itch and pain intensities were rated on visual and numerical rating scales, respectively. Dispersion of itch was drawn on arm charts. Presence and area of alloknesis and hyperknesis were determined. Group comparisons were performed in SPSS with a significant level of 0.05. Descriptive statistic was used for questionnaire’s analysis. Results:Patients(n=20;68.10±7.91y,F/Mratio:8/12)andcontrols(n=20;67.35±7.65y,F/Mratio:8/12)wereexamined.PD patients rated less physical and emotional descriptors, except for the stinging (P = 0.028). No difference was found between the groups in histamine-provoked itch intensity (P = 0.799) or the itchy area. A significantly larger area of hyperknesis was found in PD (P = 0.011), but not for the area of alloknesis (P = 0.221). Sex-related responses yielded only a tendency toward higher responses in female patients. Discussion:PDdoesnotseemtoinfluenceperceptionofitch,neitherspontaneousnorevokeditch,exceptforhyperknesisarea,which was found significantly larger in PD patients following the application of histamine. This finding proposes a potential alteration in central processing of itch that needs further investigation and whether and how it is affected by, for example, PD pathogenesis

Antidromic vasodilatation and the migraine mechanism

Despite the fact that an unprecedented series of new discoveries in neurochemistry, neuroimaging, genetics and clinical pharmacology accumulated over the last 20 years has significantly increased our current knowledge, the underlying mechanism of the migraine headache remains elusive. The present review article addresses, from early evidence that emerged at the end of the nineteenth century, the role of ‘antidromic vasodilatation’ as part of the more general phenomenon, currently defined as neurogenic inflammation, in the unique type of pain reported by patients suffering from migraine headaches. The present paper describes distinctive orthodromic and antidromic properties of a subset of somatosensory neurons, the vascular- and neurobiology of peptides contained in these neurons, and the clinical–pharmacological data obtained in recent investigations using provocation tests in experimental animals and human beings. Altogether, previous and recent data underscore that antidromic vasodilatation, originating from the activation of peptidergic somatosensory neurons, cannot yet be discarded as a major contributing mechanism of the throbbing head pain and hyperalgesia of migraine

Aquaporin 4 expression on trigeminal satellite glial cells under normal and inflammatory conditions

Abstract Aims Limited information is currently available for the expression and role of Aquaporin 4 (AQP4) (AQ4) in the peripheral nervous system (PNS). It has been demonstrated that AQP4 is expressed in sensory ganglia. Immunohistochemistry has revealed that satellite glial cells (SGCs) surrounding the cell bodies of the primary afferent sensory neurons in these sensory ganglia exclusively express AQP4 at a considerably lower level than what is seen in astrocytes. The pathophysiological relevance of AQP4 in peripheral nociception; however, remains unclear. Hence, this study aimed at investigating AQP4 expression in trigeminal neurons and SGCs under normal and inflammatory conditions relevant to craniofacial pain conditions. Methods Rat trigeminal ganglia (TG) were isolated from adult male Sprague-Dawley rats subjected to a model of trigeminal inflammation evoked by unilateral complete Freund’s adjuvant (CFA) injection in temporomandibular joint. Immunohistochemistry was performed on TG sections of CFA-treated animals. NeuN and GS markers were used for identification of neurons and SGCs, respectively. AQP4 expression was investigated in both ipsilateral and contralateral TG sections. The study protocol was approved by the local ethics committee. Results Co-localization of NeuN-AQP4 and GS-AQP4 were identified in both ipsi and contralateral trigeminal ganglia of the CFA-treated rats. However, we did not detect any difference between the ipsi- and contralateral side in terms of alteration in AQP4 receptor expression. Conclusions AQP4 was expressed both on trigeminal neurons and SGCs and CFA did not cause a remarkable change in AQP4 expression, when ipsilateral and contralateral TG of the test animals was compared. Previously, it has been shown that in a neuropathic pain model no difference is detectable between wild type and AQP4-deficient mice, for mechanical and thermal perception; however, in formalin pain model AQP4-deficient mice have higher thermal pain thresholds. Further investigation is required to clarify role of AQP4 in pain. </jats:sec

A placebo-controlled clinical trial to evaluate the effectiveness of massaging on infantile colic using a random-effects joint model

Samaneh Mansouri,1 Iraj Kazemi,2 Ahmad Reza Baghestani,3 Farid Zayeri,1 Fatemeh Nahidi,4 Nafiseh Gazerani4 1Department of Biostatistics, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 2Department of Statistics, Faculty of Sciences, University of Isfahan, Isfahan, Iran; 3Department of Biostatistics, Faculty of Paramedical Sciences, Physiotherapy Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 4Department of Midwifery and Reproductive Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran Background: Infantile colic viewed as a non-dangerous prevalent issue could lead to stress in parents and long-term negative consequences in ex-colicky children. Researchers have not been successful in finding a certain treatment for colic symptoms. Studies suggest completely different approaches as its treatment. Massage therapy as an alternative method in reducing colic symptoms has been recommended in several studies.Methods: A total of 100 colicky infants in a single blind study were randomly specified to two equal groups of intervention and control. Infants in the intervention group received massage for 15&ndash;20 minutes once during the day and once at night before sleep, while infants in the control group were rocked for 15&ndash;25 minutes when the symptoms of colic appeared. Parents recorded the details of the colic symptoms in a diary every day. All these outcomes were modeled simultaneously via a random-effects joint model.Results: Among 100 infants included in the analysis, 48% were female; 91% of all infants were breastfed and 54% of them were born via normal vaginal delivery. In general, the effect of massage therapy on colic symptoms was assessed using the joint model. Our findings illustrated that massaging colicky infants would substantially reduce colic symptoms and increase the sleep duration in babies compared with the rocking group (P&lt;0.001).Conclusion: Massage therapy could be considered as an effective method in reducing colic symptoms. Mean of the symptoms dropped significantly in the intervention group compared with that in the rocking group. Our study also represents that a relevant and correct statistical model could result in more reliable findings. Keywords: infantile colic, massage therapy, clinical trial, random-effects joint mode