جستجوی مقالات مرتبط با کلیدواژه « آلودینیا » در نشریات گروه « پزشکی »

Chronic neuropathic pain is one of the common and debilitating problems of human societies and is a challenge in health care Valerian officinalis has been used in the treatment of pain and anxiety due to its antioxidant effects and multiple mechanisms. Also, the medicinal form of emulsion is studied to increase the bioavailability and absorption of herbal products. The present study was conducted to determine the analgesic and anti-anxiety effects of the oral emulsion of the extract and compare it with the effects of the extract in adult male rats. First, the oral emulsion of the extract was formulated with the help of similar studies and Design Expert software, and the best formulation was selected. Then, neuropathic pain was induced in the animals with the help of a sciatic nerve chronic obstructive lesion (CCI) neuropathy surgical model. The extract and emulsion were given orally (gastric gavage) to the animals for 30 days, after which behavioral tests were performed, to investigate thermal allodynia, and elevated plus maze (EPM), to investigate induced anxiety behaviors, one day before Induction of neuropathy and on days 2, 4, 6, 10, 14, 21, 30 after neuropathy were investigated, and at the end, the effects of oral emulsion gavage of extract and extract on lipid peroxidation of malondialdehyde (MDA) in brain tissue were investigated and compared. Separate administration of valerian extract and emulsion reduced cold allodynia in all days after CCI surgery compared to the neuropathy group (P<0.05). In addition, CCI surgery caused anxiety in rats. Administration of valerian emulsion and its extract were able to significantly reduce anxiety in the behavioral test of the plus-shaped elevated maze. The difference is that this reduction process started earlier with the administration of the extract emulsion (P<0.001). Also, the administration of the extract and emulsion significantly reduced the amount of malondialdehyde in the brain tissue in neuropathic rats compared to the neuropathy group (P<0.001), with the difference that the emulsion of the extract caused a greater decrease in the amount of malondialdehyde compared to the extract. Valerian extract and emulsion have analgesic and anti-anxiety effects. In addition, the administration of valerian emulsion in neuropathic rats has significantly more anti-anxiety and analgesic effects compared to the administration of valerian extract.

Background and

Inflammation plays an important role in the development of neuropathic pain (NP). Considering the anti-inflammatory effects of mesenchymal stem cells (MSCs) and their conditioned medium (CM), we aimed to investigate the effect of MSC-CM on the expression of CCL3 and CCL4 genes in the spinal cord of rats with NP.

In this experimental-interventional study, 28 male Wistar rats weighing 200-300 grams were included. NP was induced in male rats using the chronic constriction injury (CCI) model of the sciatic nerve. MSCs-CM was injected intraperitoneally (1ml) into each rat in the experimental group one day before surgery (-1), and 7 and 11 days after the surgery, while the rats of control group received DMEM. At the end of the study (day 15), the expression level of CCL3 and CCL4 genes in the animals’ spinal cord was measured using Real time PCR.

Molecular studies showed a significant decrease in CCL3 gene expression (P<0.05) in CM treated animals compared to the control group, but in term of CCL4 gene expression, there was no significant difference between the groups.

Anti-NP effects of MSCs-CM seem to be partly mediated through downregulation of CCL3 chemokine in the spinal cord.

Neuropathic pain due to chemotherapy is one of the most important types of chronic pain that despite the increasing advances in medical sciences, its treatment is associated with many problems. In this study, the effects of atomoxetine on paclitaxel-induced neuropathic pain and the effect of alpha-2 adrenergic receptor antagonist (yohimbine) on the analgesic effect of atomoxetine were investigated.

Male mice received paclitaxel (2 mg/kg i.p.) from the first to the fifth day and atomoxetine (5, 10, and 15 mg/kg p.o.) was administered from the day 6 to 10. Mice were divided into different groups (n=8) and each group received a unique dose of the drug. On days 9, 10 and 11, Von Frey and acetone tests were performed. Also, the effect of alpha-2 adrenergic receptor antagonist (yohimbine) on the analgesic effect of atomoxetine was investigated. For this purpose, after pain induction, mice received atomoxetine (15 mg/kg p.o) with yohimbine (5 mg/kg i.p. 5) from day 6 to 10.

Daily administration of atomoxetine (15 mg/kg p.o) effectively increased pain threshold in the cold and mechanical allodynia tests (P<0.01). Administration a single dose of atomoxetine on the 11th day did not alter behavioral tests.

According to these findings, it can be concluded that atomoxetine is able to reduce the severity of paclitaxel-induced neuropathic pain.

Neuropathic pain is a chronic pain that results from damage to the central and peripheral nerves. According to the previous studies, physical activity or progesterone can be an effective treatment for alleviating sensory neuropathic pain individually. In this way, the combined effect of chronic progesterone and forced exercise on behavioral pain responses in the neuropathic pain model of chronic constriction injury in rats was considered.

Eighty male Wistar rats were used in 8 groups (n=10). First, neuropathic pain was induced by CCI in the respective groups. For the treatment of neuropathic pain, animals in the groups received progesterone (6 mg/kg) started 12 days after the operation until day 26. In exercise groups, the exercise started 12 days after surgery until day 33. Behavioral tests were performed on days 12 and 33.

Interestingly, we found that CCI-induced neuropathy could produce thermal hyperalgesia and mechanical allodynia in experimental groups on day 12 before exercise and progesterone therapy. After the stabilization of neuropathic pain, co-administration of progesterone (6 mg/kg) for 14 days and moderate intensity exercise for 3 weeks in the respective group could alleviate neuropathic pain compared with the CCI and each of treated groups individually.

The findings of this study showed that co-administration of chronic progesterone and forced exercise after the stabilization of neuropathic pain may alleviate neuropathic pain

Background and Purpose: Chronic neuropathic pain caused by damage or disturbance of the functioning of the somatosensory system are one of the major health problems and many people suffer from such diseases. The aim of this study was to investigate the effect of Umbelliprenin (UMB) on the symptoms of neuropathic pain in chronic constriction injury model (CCI) of neuropathy in adult male rats. 24Wistar rats (250±20g) were randomly divided into 3 groups: sham, CCI and CCI+UMB (100μg/rat) groups. UMB was injected intrathecaly one day before surgery, and 3 days after surgery. Von Frey and Hot-Plate tests were performed one day before surgery and on days 2, 4, 7, 10 and 14 after surgery. The results were reported as mean and SEM (P

Role of NMDA receptors in persistence of pathological pain is not clear. In addition, long-term potentiation (LTP) has a crucial role in development and maintenance of neuropathic pain. The aim of this study was to investigate the role of glutamate NMDA receptor and electrophysiological changes in spinal dorsal horn following L5 spinal nerve ligation.

The model of spinal nerve  ligation (SNL) was used in this study. In behavioral experiments to evaluate mechanical allodynia, Von frey filaments were used from a day before induction of neuropathy up to 7 days after neuropathy. Memantin 10 mg/Kg, i.p.,  as NMDA antagonist, was injected one hour before SNL up to 7 days afer SNL. LTP induction  and dorsal horn WDR neurons recording was performed by spinal single unit set up on day 7 after high frequeny stimulus (HFS) induction.

SNL induced mechanical allodynia . Daily injection of memantin increased thershold of pain significantly (p < 0.01) at the period of maximum pain (days 5, 6 and 7). Electrophsiological recording showed a significant decrease in the thershold of activation of C and Aδ fibers or LTP induction (p < 0.001) 7 days after SNL, compared to sham group. Daily administration of memantin prevented  induction of LTP.

It seems that NMDA receptors are involved in development of plasticity during neuropathic pain. Control of neuropathic pain by memantin might open a new insight  in treatment of neuropathic pain.

Neuropathic pain is a chronic pain that affects on the patient’s quality of life. Use of herbal instead of synthetic drugs recently has been increased due to side effects of synthetic drugs and herbal effective components. Flavonoids are herbal compounds that have analgesic and anti-inflammatory effects. Because Allium cepa L. has a great amount of flavonoids, this study has been designed to evaluate analgesic effects of alcoholic extract of Allium cepa L. on neuropathic pain behavior in chronic constriction injury model in rats.
In this experimental study, neuropathic pain induced by chronic constriction injury (CCI model) in Rats. Animals were randomly divided into 4 groups (n=10 for each): Sham, CCI model, receiving red onion hydroalcoholic extract at a dose of 100 mg/kg and a group receiving gabapentin (100 mg/kg). Red onion extract and gabapentin were administered by gavage for 21 days. Using thermal hyperalgesia, mechanical and thermal allodynia tests, the analgesic effects of extract have been measured.
Findings of this study revealed that CCI surgery on rats induced hyperalgesia, mechanical and thermal allodynia. Daily intakes of alcoholic extract of red onion and gabapentin significantly increase the paw withdrawal latency; increase the threshold to mechanical allodynia and decrease in response to acetone.
Oral use of alcoholic extract of Allium cepa L. reduces neuropathic pain behavior in CCI model in rats.

Induced neuropathic pain following nerve injury has behavioral signs such as allodynia and hyperalgesia. There are reports about the age dependent differences in severity and incidence and even therapeutic response of this pain. In this study, we have tried to evaluate behavioral differences of this pain in an induced neuropathic model in different ages, according to important role of N-methyl, D-aspartate (NMDA) receptor and spinal microglia on induction and maintenance of pain. Male rats were grouped in young (5-6 week) and mature (10-11 week). Under general anesthesia, the spinal nerve ligation (SNL) surgery was operated on right leg. The effect of different doses of dextromethorphan (NMDA blocker) and minocycline (microglia inhibitor) on 5th day after surgery was evaluated and compared in two age-groups. In this study, both Minocycline and dextromethorphan diminished neuropathic pain in a dose dependent manner in these two ages. Minocycline in contrast to dextromethorphan was more effective in young rats. The co-administration of ineffective doses of minocycline and dextromethorphan could be effective. Microglia and NMDA receptor function in neuropathic pain is different in different ages and the role of microglia is more evident. On the other hand the inhibition of both microglia and NMDA receptor can be considered for lowering neuropathic pain.

The mechanisms underlying neuropathic pain are complex and remain controversial. From the proposed mechanisms we can refer to loss of GABAergic inhibition and glial activation in the spinal dorsal horn. As for the discrepancies in the neuropathic pain mechanisms, in the present study, we examined whether the GABA-A receptor agonist muscimol and glial inhibitor pentoxifylline would modify behavioral tests in rats with Chronic Constriction Injury (CCI). In this study male wistar rats (200-250 g) were used and for neuropathy induction, the CCI model (Bennett method, 1988) was used. In the sham group, after exposing the sciatic nerve, surgery region was closed. Pentoxifylline was administered one day before neuropathy to 14 days after CCI (30 mg/kg daily) and behavioral tests (plantar test and von frey) were performed one day before surgery and then on days 1, 4, 7 and 14 after surgery and 30 minutes after pentoxifylline adminstration. In groups that received muscimol with doses 0.5, 1 and 2 mg/kg on day 14 after CCI, behavioral tests were experienced before and 30 minutes after drug administration. Behavioral assessment indicated that CCI induce symptoms of neuropathic pain but both muscimol and pentoxifylline could reduce pain behavioral responses. It seems that this reduction of muscimol (1 and 2 mg/kg) was more effective in thermal hyperalgesia than pentoxifylline, and for pentoxifylline (30 mg/kg) was more effective in mechanical allodynia than muscimol. present data showed that muscimol via activation of GABA-A receptors and pentoxifylline via glial inhibition reduced behavioral symptoms of neuropathic pain after spinal cord injury.

The underlying central mechanisms for the development and maintenance of neuropathic pain are unknown. The current study aimed to evaluate the long-term potentiation (LTP) changes in spinal dorsal horn wide dynamic range (WDR) neurons following a peripheral neuropathy model. This study was conducted on 26 male Wistar rats. The spinal nerve ligation (SNL) model was performed to induce neuropathy. After surgery, thermal hyperalgesia and mechanical allodynia were evaluated one day before neuropathy, and then on days 2, 5, 7, 14, 21 and 28 after neuropathy. Single-unit recording was used to study the changes of LTP. The changes of LTP and Aδ- and C-fiber evoked responses by high-frequency stimulation (100 Hz and current intensity six times that of the threshold for activation of C- fibers) of sciatic nerve in spinal WDR synapses were studied on day 14 after surgery up to 2 hours. Neuropathy was induced thermal hyperalgesia and mechanical allodynia on day 2 and persisted for 28 days after neuropathy. Electrophysiological recording revealed that HFS induced LTP either in the Aδ- or in the C-fibers in both sham and neuropathy groups up to 2 hr on day 14 after neuropathy. Neuropathy also significantly decreased the threshold of these fibers. LTP-induced HFS in spinal WDR neurons can be one of the underlying central mechanisms in the maintenance of neuropathic pain.

Considering the side effects of chemical drugs, several studies have been conducted to investigate the analgesic effect of plants. The aqueous extract of Elaeagnus angustifolia L. contains high levels of polyphenols and flavonoids. Considering the analgesic effect of such compounds, this study was designed to estimate the analgesic effect of the E. angustifolia aqueous extract in rats. In this experimental study, 50 male Wistar rats were randomly allocated into 5 groups (n=10 for each): the groups received the E. angustifolia aqueous extract (50, 100, 200 and 400 mg/kg) and control group. The aqueous extract was administered through gavage every day for 4 weeks. Finally, the pain level was evaluated using the mechanical and thermal allodynia, thermal hyperalgesia and formalin tests. Our results showed that supplementation of E. angustifolia aqueous extract significantly reduced pain scores in thermal allodynia, mechanical allodynia, hyperalgesia and formalin test (P<0.05). Aqueous extract of E. angustifolia has a prominent dose-dependent analgesic effect on rats.

Neuropathic pain is caused by a lesion or disease of the peripheral or central nervous system. Since, treatment of neuropathic pains remains a challenge. The purpose of the present study was to examine the effect of ethosuximide, an anti-epileptic and relatively selective T-type calcium blocker, on the behavioral responses following chronic constriction pain (CCI) induced in rats. Experiments were performed on six groups (n=8) of male Sprague-Dawley rats (230-280g).The study consisted of a control and an induced chronic constriction of the sciatic nerve (CCI) groups, 3 groups receiving ethosuximide with concentrations 100, 200, 300 mg/kg,and one group which received normal saline. The cold-and mechano-allodynia and thermal hyperalgesia were measured prior to surgery (the day 0) and 3, 5, 7, 14 and 21 days postsurgery. Statistical analysis of repeated ANOVA was used to compare the results of behavioral tests by means of SPSS software (V:16) It was found that the CCI group significantly produced mechanical and cold allodynia and a hypersensitivity to noxious stimulations. Ethosuximide significantly decreased cold and mechano-allodynia and thermal hyperalgesia. The results suggested that the CCI model significantly influences behavioral responses to both the thermal and mechanical stimulations. Besides, systemic administration of ethosuximide significantly decreases behavioral responses of neuropathic pain induces through CCI. Thus, ethosuximide can be taken as a new potential therapeutic drug used against neuropathic pain

Neuropathic pain is a type of chronic pain resulting from injury to the peripheral or central nervous system. Moreover, lithium is the main medication used to treat bipolar (manic-depression) disorder and some recent studies have also confirmed the neuroprotective effects of lithium. Considering the most common cause of neuropathic pain, nerve injury, the present study was designed to evaluate the effect of lithium on neuropathic pain induced by partial ligation of sciatic nerve in rat.

This experimental study was conducted on 40 adult male rats. Neuropathic pain was induced by a partial sciatic nerve ligation model and animals were randomly divided into five groups: a control group that underwent the surgical procedure without sciatic nerve ligation and four experimental groups which received normal saline and different doses of lithium (5, 10 and 15 mg/kg, i.p.). Heat hyperalgesia, mechanical and cold allodynia were assessed at 3, 5, 7, 10 and 14 days after surgery.

According to the results, lithium (5, 10 and 15 mg/kg) significantly reduced heat hyperalgesia and cold allodynia induced by partial sciatic nerve ligation (P<0.01), while it reduced mechanical allodynia only at high doses (10 and 15 mg/kg).

Lithium has an analgesic effect on neuropathic pain induced by partial ligation of sciatic nerve in rat. Further investigations would be needed to confirm the analgesic effect of lithium and its mechanisms of action in neuropathic pain.

Glial activation and secretion of cytokines at the spinal level is known as part of chronic pain pathogenesis. Although changes in TNFα at the supraspinal level are reported during chronic pain, its exact role and site of action remain to be elucidated. We investigated the effect of microinfusion of TNFα into the LC in a rat model of neuropathic pain. Male Wistar rats were cannulated in the LC. The cannula was connected to an Alzet mini-osmotic pump, which was filled by the drug (vehicle, TNFα or TNFα-antibody) and placed subcutaneously behind the neck. Twenty four-48 hours after cannulation, a chronic constriction injury (CCI) surgery was performed on the contralateral sciatic nerve. Hyperalgesia and allodynia symptoms were assessed 2, 4, 6, 8, 10 and 12 days after CCI. Microinfusion of TNFα (100ng/day) into the LC significantly exacerbated the hyperalgesia in rat models of neuropathic pain on days 2 and 8 after CCI. On the other hand, microinfusion of TNFα antibody (250ng/day) decreased the symptoms of hyperalgesia on days 2, 4, 6, 8, 10 and 14. TNFα antibody also significantly alleviated the CCIinduced allodynia. These data suggest that alterations of TNFα levels in the LC play a crucial role in the development and maintenance of neuropathic pain.

Damage to neural pathways is one of the most significant factors of neuropathic pains, which is characterized by spontaneous burning pain accompanied by allodynia and hyperalgesia. The present study was carried out to explore behavioral and electrophysiological characteristics of neuropathic pain model of Spared Nerve Injury (SNI). In this experimental study, male Sprague-Dawley rats (wt: 230-280 Gms.) were used. Anesthesia was initially induced with sodium pentobarbital (ip) at a dose of 50 mg/kg. Then, SNI surgery operation was performed on them. The animals were tested for their behavioral responses shown as heat and mechano-allodynia and heat and mechano-hyperalgesia prior to the surgery ("0" day), and on the 3rd, 7th, 14th, 21st and 28th day post- operation. Electrophysiological responses by the sciatic nerve were recorded two weeks after the operation. Stimulation of the sural nerve branch and proximal area of auxotomized nerve were recorded proximally. Repeated ANOVA and one-way ANOVA statistical softwares were applied to the results of behavioural testing and electrophysiological responses, respectively. P≤0.05 was considered as the significant level. Compared to the control group, the rats in the SNI group revealed an obvious difference in their behavioral responses towards heat and mechano-stimulation manifested by allodynia and hyperalgesia, respectively (P<0.05, P<0.01). Conduction velocity (CV) significantly reduced in SNI rats compared to the control group (P<0.05). Amplitude also slightly decreased in the SNI group. Compound action potential (CAP) rising time was similar in both SNI and the control animals. SNI models showed acute behavioural responses to both thermal and mechanical allodynia and hyperalgesia stimuli. Besides, electrophysiological recordings of the nerve confirmed nerve damage and injury due to this model, which caused a decrease in nerve conduction.

Neuropathic pain syndromes are changes resulted from damage to nervous system. Since, treatments of neuropathic pain are poorly understood, existing treatments are often ineffective, and also experimental studies have documented that MK-801, a NMDA receptor antagonist, attenuates neuropathic pain, the purpose of this study was to investigate the behavioral responses and involvement of pre-emptive treatment of morphine and / or NMDA receptor antagonist MK-801, in Spared Nerve Injury (SNI) model of neuropathic pain. Experiments were performed on six groups (n=8) of male Sprague-Dawley rats (230-280g). Two animal groups were injected MK-801 (0.3 mg/kg, 20 min before, and 6 h after the operation) or morphine (8 mg/kg, 30 min prior to the operation). The third group was received both drugs with the same doses and protocols. Finally, the fourth group was received an equal volume of saline. Then, SNI procedure was performed by a ligation and axotomy of the tibial and common peroneal nerves and the sural nerve was left intact. The animals were tested for allodynia and hyperalgesia reactions at 0, 3, 7, 14, 21 and 28 days after performing SNI procedure of the sciatic nerve. Statistical analysis was performed using repeated measures ANOVA and the Tukey HSD test. Our data revealed that the SNI produces mechanical and cold allodynia and a hypersensitivity to noxious stimulations. Co-injection of morphine and MK-801 markedly declined cold allodynia at the day 14 (P<0.05) when compared with the saline group. The results of present study demonstrate that SNI model importantly influences the behavioral responses to both thermal and mechanical stimulations. It seems that co-administration of both drugs attenuates neuropathic pain in rat.

Neuropathic pain syndromes are changes resulted from damage to neuronal pathways which is characterized by spontaneous burning pain with accompanying allodynia and hyperalgesia. The mechanisms underlying neuropathic pain are poorly understood. The present study explores behavioral characteristics of the neuropathic pain models chronic constriction injury (CCI) and spared nerve injury (SNI). Experiments were performed on four groups (n= 8) of male Sprague-Dawley rats (230-280 g). Anesthesia was initially induced with sodium pentobarbital (i.p.) at a dose of 50 mg/kg. The CCI model was made by loose ligation of the sciatic nerve. Also a lesion of two of three terminal branches of the sciatic nerve leads to a SNI model. The animals were tested for behavioral responses cold-and mechano-allodynia and heat-and mechano-hyperalgesia. The cold and mechanical stimulations in the cold- and mechano-allodynia phenomena were applied through acetone and von Frey filament respectively. Pin-prick and radiant heat were applied as thermal and mechanical stimulations in the heat- and mechano-hyperalgesia respectively. Behavioral tests were conducted on the animals prior to surgery (the day 0), and 3, 7, 14, 21 and 28 days post-operation. Our results indicate that, in comparison to the controlled group, the rats in both SNI and CCI groups reveal an obvious difference in behavioral responses. Although the SNI, compared to the CCI group were more sensitive to mechano-allodynia shortly after surgery (p<0.5) however, both groups share a similar pattern of behavior. In the heat-hyperalgesia testing, again, the animals in the CCI and SNI groups behaved differently than those in the controlled group, but no variation was evident among the test groups, themselves. These findings clearly show that the two neuropathic models produce abnormal pain-related disorders in the rats. A major feature of the SNI model was the very marked hypersensitivity to normally innocuous mechanical stimuli.