Root Ganglion Research Articles

The RS504393 Influences the Level of Nociceptive Factors and Enhances Opioid Analgesic Potency in Neuropathic Rats

Increasing evidence has indicated that activated glial cells releasing nociceptive factors, such as interleukins and chemokines, are of key importance for neuropathic pain. Significant changes in the production of nociceptive factors are associated with the low effectiveness of opioids in neuropathic pain. Recently, it has been suggested that CCL2/CCR2 signaling is important for nociception. Here, we studied the time course changes in the mRNA/protein level of CD40/Iba-1, CCL2 and CCR2 in the spinal cord/dorsal root ganglia (DRG) in rats following chronic constriction injury (CCI) of the sciatic nerve. Moreover, we examined the influence of intrathecal preemptive and repeated (daily for 7 days) administration of RS504393, CCR2 antagonist, on pain-related behavior and the associated biochemical changes of some nociceptive factors as well as its influence on opioid effectiveness. We observed simultaneous upregulation of Iba-1, CCL2, CCR2 in the spinal cord on 7th day after CCI. Additionally, we demonstrated that repeated administration of RS504393 not only attenuated tactile/thermal hypersensitivity but also enhanced the analgesic properties of morphine and buprenorphine under neuropathy. Our results proof that repeated administration of RS504393 reduced the mRNA and/or protein levels of pronociceptive factors, such as IL-1beta, IL-18, IL-6 and inducible nitric oxide synthase (iNOS), and some of their receptors in the spinal cord and/or DRG. Furthermore, RS504393 elevated the spinal protein level of antinociceptive IL-1alpha and IL-18 binding protein. Our data provide new evidence that CCR2 is a promising target for diminishing neuropathic pain and enhancing the opioid analgesic effects.

Uterine Cervical Neurotransmission and Cervical Remodeling.

Cervical remodeling (CR) is a complex process, which, in part, is believed to be induced by physiological inflammation. Even though the female reproductive tissues are richly innervated by nerves from the parasympathetic pelvic autonomic ganglia, sensory dorsal root and nodose ganglia, their roles (neuronal factors) in this process (CR) has been largely attributed to sex steroid hormones, until recently. Here, we discuss the interaction between neuropeptides derived from peripheral nerves associated with uterine cervix and estrogen, and their likely impact on cervical remodeling. It is likely that these neuronal factors, under the influence of estrogen, could induce physiological inflammation during cervical remodeling by promoting the expression of vascular endothelial growth factor, among other factors.

Pathologic Studies of Fatal Encephalomyelitis in Children Caused by Enterovirus 71.

Enterovirus 71 (EV71) is the major pathogen of hand, foot, and mouth disease and can cause death; however, its pathogenesis remains elusive. We performed a detailed systematic histopathologic examination and molecular studies on six autopsy cases of EV71 infection using H&E, immunohistochemistry, double immunofluorescence staining, and nested reverse transcription polymerase chain reaction. Characteristic features of acute encephalomyelitis were observed. Viral antigens were mainly detected in neuronal cytoplasm and processes in the different brainstem nuclei and spinal cord, including the anterior and posterior horn cells. Viral antigens were also positive in the nerve roots of spinal cord and autonomic ganglia of intestines. Our study revealed direct pathologic evidence supporting viral entry into the central nervous system (CNS) through peripheral nerves. In addition to the major motor pathway, EV71 can also enter the CNS via peripheral sensory and autonomic pathways in retrograde axonal transport.

SPARCL1-containing neurons in the human brainstem and sensory ganglion

Secreted protein, acidic and rich in cysteine-like 1 (SPARCL1) is a member of the osteonectin family of proteins. In this study, immunohistochemistry for SPARCL1 was performed to obtain its distribution in the human brainstem, cervical spinal cord, and sensory ganglion. SPARCL1-immunoreactivity was detected in neuronal cell bodies including perikarya and proximal dendrites, and the neuropil. The motor nuclei of the IIIrd, Vth, VIth, VIIth, IXth, Xth, XIth, and XIIth cranial nerves and spinal nerves contained many SPARCL1-immunoreactive (-IR) neurons with medium-sized to large cell bodies. Small and medium-sized SPARCL1-IR neurons were distributed in sensory nuclei of the Vth, VIIth, VIIIth, IXth, and Xth cranial nerves. In the medulla oblongata, the dorsal column nuclei also had small to medium-sized SPARCL1-IR neurons. In addition, SPARCL1-IR neurons were detected in the nucleus of the trapezoid body and pontine nucleus within the pons and the arcuate nucleus in the medulla oblongata. In the cervical spinal cord, the ventral horn contained some SPARCL1-IR neurons with large cell bodies. These findings suggest that SPARCL1-containing neurons function to relay and regulate motor and sensory signals in the human brainstem. In the dorsal root (DRG) and trigeminal ganglia (TG), primary sensory neurons contained SPARCL1-immunoreactivity. The proportion of SPARCL1-IR neurons in the TG (mean ± SD, 39.9 ± 2.4%) was higher than in the DRG (30.6 ± 2.1%). SPARCL1-IR neurons were mostly medium-sized to large (mean ± SD, 1494.5 ± 708.3 μm2; range, 320.4–4353.4 μm2) in the DRG, whereas such neurons were of various cell body sizes in the TG (mean ± SD, 1291.2 ± 532.8 μm2; range, 209.3–4326.4 μm2). There appears to be a SPARCL1-containing sensory pathway in the ganglion and brainstem of the spinal and trigeminal nervous systems.

(366) Voluntary activity prevents muscle IL1β upregulation to inhibit the development of ischemic myalgia

Issues of peripheral circulation have been increasingly suggested as an underlying cause of musculoskeletal pain in many clinical conditions. In a model of ischemia and reperfusion injury (I/R), we have previously shown in male Swiss Webster mice that I/R induces alterations in chemosensitivity and mechanical thresholds of individual group III and IV muscle afferents as assessed with an ex vivo muscle-nerve-dorsal root ganglion (DRG)-spinal cord recording preparation. We have also shown that I/R increases pain-related behaviors while decreasing muscle strength and voluntary activity. This appeared to be due to enhanced interleukin 1β (IL1β) in the injured muscles and its receptor IL1 receptor 1 (IL1r1) within the DRGs, as an afferent-specific knockdown of IL1r1 inhibited I/R-induced changes in afferent response properties and animal behaviors. Here we show that voluntary wheel running prior to I/R prevented the injury-induced increase in muscle IL1β and the subsequent development of spontaneous (guarding) and evoked (von Frey mechanical stimulation) pain-related behaviors, as well as attenuating I/R-induced deficits in grip strength and voluntary activity. In addition, systemic injection of the IL1 receptor antagonist (IL1RA), which would block effects of IL1β during I/R, was also found to prevent injury-induced upregulation of IL1r1 within the DRGs, and recapitulated most of the preventative effects of exercise or nerve-specific IL1r1 knockdown on I/R-related behaviors. IL1RA-treated animals, however, still experienced an I/R-induced grip strength deficit, suggesting that systemic inhibition of IL1β may potentially have other effects on muscle function. Nevertheless, IL1RA was still found to block I/R-induced changes in mechanical thresholds and chemosensitive muscle afferent prevalence. Altogether, these data strengthen the evidence that increased IL1β in the muscles during I/R sensitizes group III and IV muscle afferents, leading to the development of muscle pain. This work also suggests potential therapies for prevention of persistent muscle pain initiated by an ischemic insult. Issues of peripheral circulation have been increasingly suggested as an underlying cause of musculoskeletal pain in many clinical conditions. In a model of ischemia and reperfusion injury (I/R), we have previously shown in male Swiss Webster mice that I/R induces alterations in chemosensitivity and mechanical thresholds of individual group III and IV muscle afferents as assessed with an ex vivo muscle-nerve-dorsal root ganglion (DRG)-spinal cord recording preparation. We have also shown that I/R increases pain-related behaviors while decreasing muscle strength and voluntary activity. This appeared to be due to enhanced interleukin 1β (IL1β) in the injured muscles and its receptor IL1 receptor 1 (IL1r1) within the DRGs, as an afferent-specific knockdown of IL1r1 inhibited I/R-induced changes in afferent response properties and animal behaviors. Here we show that voluntary wheel running prior to I/R prevented the injury-induced increase in muscle IL1β and the subsequent development of spontaneous (guarding) and evoked (von Frey mechanical stimulation) pain-related behaviors, as well as attenuating I/R-induced deficits in grip strength and voluntary activity. In addition, systemic injection of the IL1 receptor antagonist (IL1RA), which would block effects of IL1β during I/R, was also found to prevent injury-induced upregulation of IL1r1 within the DRGs, and recapitulated most of the preventative effects of exercise or nerve-specific IL1r1 knockdown on I/R-related behaviors. IL1RA-treated animals, however, still experienced an I/R-induced grip strength deficit, suggesting that systemic inhibition of IL1β may potentially have other effects on muscle function. Nevertheless, IL1RA was still found to block I/R-induced changes in mechanical thresholds and chemosensitive muscle afferent prevalence. Altogether, these data strengthen the evidence that increased IL1β in the muscles during I/R sensitizes group III and IV muscle afferents, leading to the development of muscle pain. This work also suggests potential therapies for prevention of persistent muscle pain initiated by an ischemic insult.

Dual Modulation of Nociception and Cardiovascular Reflexes during Peripheral Ischemia through P2Y1 Receptor-Dependent Sensitization of Muscle Afferents.

Our current results suggest that P2Y1 modulates heat responsiveness and chemosensation in muscle afferents to play a key role in the development of pain-related behaviors during ischemia. At the same time, under these pathological conditions, the changes in muscle sensory neurons appear to modulate an increase in mean systemic blood pressure after exercise. This is the first report of the potential peripheral mechanisms by which group III/IV muscle afferents can dually regulate muscle nociception and the exercise pressor reflex. These data provide evidence related to the potential underlying reasons for the comorbidity of muscle pain and altered sympathetic reflexes in disease states that are based in problems with peripheral perfusion and may indicate a potential target for therapeutic intervention.

Multimodal perineural analgesia with combined bupivacaine-clonidine-buprenorphine-dexamethasone: safe in vivo and chemically compatible in solution.

The use of adjuvants in regional anesthesia has increased. However, there are knowledge gaps pertaining to 1) in vivo local tissue effects of these adjuvants; and 2) chemical compatibility and solubility of these drugs in solution with each other and with local anesthetics. This study addresses these gaps in knowledge. In vivo rat safety/toxicopathology study and analytical chemistry study. Collaborating Good Laboratory Practice laboratories under the direction of the university-based principal investigator. Single-injection formulations of clonidine, buprenorphine, and dexamethasone were combined with either bupivacaine or midazolam, and were administered to groups of rats. Post-injection behavior was monitored to assess changes related to the block. A continuous infusion of bupivacaine, clonidine, and dexamethasone was administered to another group of rats, and behavioral effects were recorded. After 15 days, rats were sacrificed and their nerves/dorsal root ganglia were examined by the pathologist. Samples of combined drug solutions were processed at an analytical chemistry laboratory for compatibility, solubility, and stability. Each of the single-injection formulations produced reversible sensory and/or motor block. None of the study drugs caused damage to any of the nerve segments or related tissue. The text describes the concentrations at which compatibility and solubility of the combined drug solutions were achieved. Four-drug single-injection formulations are described that 1) had compatible and stable concentrations in solution; and 2) produced reversible nerve block without causing long-term motor or sensory deficits or damage to sciatic nerves/dorsal root ganglia.

Genesis of anxiety, depression, and ongoing abdominal discomfort in ulcerative colitis-like colon inflammation.

Psychological disorders are prevalent in patients with inflammatory bowel disease; the underlying mechanisms remain unknown. We tested the hypothesis that ulcerative colitis-like inflammation induced by dextran sodium sulfate (DSS) exacerbates the ongoing spontaneous activity in colon-projecting afferent neurons that induces abdominal discomfort and anxiety, and depressive-like behaviors in rats. In this study, we used the conditioned place preference and standard tests for anxiety- and depression-like behaviors. DSS rats developed anxiety- and depression-like behaviors 10 to 20 days after the start of inflammation. Single-fiber recordings showed an increase in the frequency of spontaneous activity in L6-S1 dorsal root ganglion (DRG) roots. Prolonged desensitization of transient receptor potential vanilloid 1 (TRPV1)-expressing colonic afferents by resiniferatoxin (RTX) suppressed the spontaneous activity, as well as the anxiety- and depressive-like behaviors. Reduction in spontaneous activity in colon afferents by intracolonic administration of lidocaine produced robust conditioned place preference (CPP) in DSS rats, but not in control rats. Patch-clamp studies demonstrated a significant decrease in the resting membrane potential, lower rheobase, and sensitization of colon-projecting L6-S1 DRG neurons to generate trains of action potentials in response to current injection in DSS rats. DSS inflammation upregulated the mRNA levels of transient receptor potential ankyrin 1 and TRPV1 channels and downregulated that of Kv1.1 and Kv1.4 channels. Ulcerative colitis-like inflammation in rats induces anxiety- and depression-like behaviors, as well as ongoing abdominal discomfort by exacerbating the spontaneous activity in the colon-projecting afferent neurons. Alterations in the expression of voltage- and ligand-gated channels are associated with the induction of mood disorders following colon inflammation.

EHMTI-0127. Three faces of pain-herpes zooster ophthalmicus

Background Herpes zoster ophthalmicus (HZO) occurs only the people who have been previously infected with varicella zooster virus (VZV). Primary infection is a chickenpox (95% VZV seropositivive in US adults). Reactivated forms its dormant status is the dorsal root, cranial nerve and other sensory ganglia may lay for years to decades. Reactivation of latens VZV localizated cutaneous rash erupting a single dermatome. It may travel along a sensory axon of the skin from vesicular lesions. Perineuritis causes intensive pain in the nerve distributionLifetime reactivation of VZV as shingles 50% incidence, HZO is rare (10-20%) of all VZV causes. HZO is a trigeminal manifestation of VZV. Reactivated VZV travels down V/1 and V/2 centripetal distribution. Contagious spread of the VZV may lead of the involvement of the other cranial nerves resulting optic neuropathy (II) isolated cranial nerve palsies (III. IV. especially IV.) neurogene motility disorders. Predisposing factors: immunecompromissed condition (decreased T-cell activity), acute herpes simplex virus infection and other reacting factors. Complications 50% of HZO patient is a postherpetic neuralgia (20% of a cases) involves the orbit (10-25% of a cases). Acute management: antiviral agent immediately-best prognosis started early-within 72 hours and general measures, ophthalmology consultation. Pain management: acute and postherpetic neuralgia. Our patient evaluated for left sided facial pain, unilateral “burning eye” and malaise that began two days ago. The neurological examination has been proven partially n. oculomotorius palsy of the left side and hyperaesthesia in dermatome V/1 unilateral side. Neuroimaging studies (cerebral and orbital CT and MRI) have shown normal status. Two days later on the face in the V/1 and V/2 dermatome we detected special characteristic skin symptom.

Deciphering the axonal transport kinetics of neurofilaments using the fluorescence photo-activation pulse-escape method

Neurofilaments, one of cytoskeletal filaments determining the axonal calibers, are transported by molecular motors along microtubule tracks in a stochastic manner named ‘stop and go’[1,2,4,7], which is called the slow axonal transport. Experiments using photo-bleached live-cell imaging observed that the slow axonal transport of NFs is characterized by a rapidly intermittent, bidirectional movement [1,3]. The overall process of brief moving interspersed by short or long term pausing can be modeled by a well-tested mathematical model [5,6], where NFs could stay on-track running, on-track pausing and off-track pausing for both anterograde and retrograde directions. The shortage of photo-bleached live-cell imaging is that it under-estimates the population of NFs which stay in the long-term pausing state. Fluorescence photo-activation pulse-escape method is designed to observe the long-term decay of the total population of NFs, which can provide accurate information about the time that NFs stay off-track. We developed a systematical method based on the model [6] and analyzed the pulse-escape experimental data in Superior Cervical Ganglion (SCG) and Dorsal Root Ganglion (DRG) neurons. The fluorescence decay of the photo-activated neurofilaments can be fit by a double exponential function, where we can extract the short-time initial decaying rate and long-term decaying rate; simultaneously, those two rates can be obtained by solving the partial differential equation which describes the stochastic movement of NFs. By using those two conditions we constrain our parameter space such that we can find a unique set of transition rates that describe the kinetics of NFs. Therefore, all the other dynamic characterization such as the average velocity of NFs, average on-track running and pausing, off-track pausing time, percentage of population of NFs at each state can all be predicted. An important advantage of our new analytical approach is that it can permit the characterization of neruofilament transport in mature axons for which single-neurofilament tracking is optically challenging due to the thickness or abundance of neurofilaments. This combined experimental and computational approach is a powerful tool for the analysis of the moving and pausing behavior of neurofilaments in axon.

Interventional Procedures of the Spine

Different interventional procedures performed under imaging guidance permit the diagnosis and treatment of the many causes of back pain. Sources of pain amenable to be treated include facet joints, vertebral body, intervertebral disk, and paraspinal structures including nerves and ganglion roots. These procedures may be merely diagnostic, therapeutic, or intended for both purposes. We review the main indications, advantages, and complications of these techniques.

Herpes zoster (shingles).

This infection is caused by reactivation of varicella-zoster virus (VZV), which may remain latent in the dorsal root and cranial nerve ganglia for decades. Reactivation often occurs for no apparent reason, although stress and immunosuppression may increase the risk.

887 Analgesic Action of Resolvin D1 to Combat Visceral Pain in a Rat Model of Visceral Hypersensitivity

G A A b st ra ct s root ganglia (DRG) neurons. The aim of this study was to examine the downstream signaling pathways mediating these effects, with the focus on Smad 3 and TRPV1. Methods: In vitro patch clamp studies were performed on dissociated DRG neurons. For in vivo studies, CP was induced by intraductal injection of trinitrobenzene sulfonic acid (TNBS) in adult male rats, with controls receiving the same volume of vehicle, followed by intrapancreatic injection of DiI, a retrograde neuronal tracer, to label the DRG neurons that project to pancreas. Three weeks later, SIS3 (2.5mg/kg i.p. daily) was administered for 1 week. Subsequently, thoracic DRGs were harvested and stained for pSmad3 using immunohistochemistry. Phosphorylated Smad3 (pSmad3), Smad3 and TRPV1 protein levels in the thoracic DRGs (T8T12) were measured using immunoblot assay. Results: DRG cells were cultured with vehicle (1μg/ml DMSO-solvent for SIS3), TGF β1(10ng/ml), SIS3-TGF β1(10ng/ml-0.3μM), respectively for 48 hours and then TRPV1 currents were determined by the response to 1μM of capsaicin. TGFβ1 significantly enhanced TRPV1 currents in DRG neurons in culture (99.06±24 pA/pF; n=6) compared to controls (44.77±14 pA/pF; n=8), an effect that was blocked by SIS3 (26.23±4.4 pA/pF; n=6) (p<0.01 by ANOVA). However, sis3 was unable to block TRPA1 currents induced by mustard oil, attesting to the relative specificity of this effect. In vivo, as shown previously, SIS3 significantly attenuates both somatic referred hypersensitivity (measured by VFF) and pancreatic hyperalgesia (measured by behavioral response to pancreatic electrical stimulation) in rats with CP. pSmad3 positive neurons in the DiI-labeled thoracic neurons were significantly increased in CP rats (79.06±4.72% compare with control 67.15±1.53%, p<0.05), which can be reduced by treatment with SIS3 (63.64±2.21%, P<0.05). Immunoblot confirmed that pSmad3 levels, but not total Smad3, were significantly reduced in the DRGs (T8-T12) of rats treated with SIS3 relative to vehicle treated rats (P<0.05). Finally, compared with vehicle treatment we found that SIS3 significantly reduced TRPV1 protein levels in rats with CP (106.11±9.44 vs 70.32±6.17, P<0.05). Conclusions: The present results demonstrate a novel link between TGFβ1 signaling and TRPV1 function and expression, an effect that appears to be mediated by Smad3. These results provide the fundamental basis for developing novel therapeutic approaches for CPinduced pain.

S3-4 H2S targets transient receptor potential receptors to relieve from inflammation and pain

Transient Receptor Potential Vanilloid 4 (TRPV4) and Transient Receptor Potential Ankyrin 1 (TRPA1) are present both in sensory neurons and in intestinal epithelial cells, where their activation causes intracellular calcium mobilization. Activation of each receptor in sensory neurons conveys pro-nociceptive signals, while in intestinal epithelial cells, their activation confers a pro-inflammatory phenotype with chemokine release. Further, TRPV4 or TRPA1 activation in mouse intestine induced visceral hyperalgesia and colitis, confirming that these channels could participate to intestinal pain and inflammation. We hypothesized that H 2 S is able to regulate TRPV4 and TRPA1functions in intestinal epithelial cells and sensory neurons. Methods TRPV4 and TRPA1 responses were evaluated by measuring calcium flux with a Fluo-8 probe in HEK cells transfected with TRPV4 or with TRPA1, but also in normal derived Colon Mucosa (NCM460) cells, Caco-2 cells (an intestinal epithelium cell line) and mouse DRG (dorsal ganglion roots) primary neurons. Cells were pre-exposed to Sodium Hydrogen Sulfide (NaHS) a H 2 S donor, or their vehicle, 3-min before a second stimulation with the specific agonist of TRPV4, 4 α PDD (4 α -phorbol-12,13-didenoate), the agonist of TRPA1 allyl isothiocyanate (AITC) or vehicle. IL-8 expression was also evaluated after 6 h of treatment with NaHS and TRPV4 or TRPA1 stimulation. Results 4 α PDD or AITC but not NaHS increased the intracellular calcium concentration respectively in HEK TRPV4 and HEK TRPA1. TRPV4 or TRPA1 agonist induced a dose-dependent calcium flux in NCM460 cells, Caco-2 cells and neurons. Incubation of NCM460 and Caco-2 cells with NaHS (200–1000 μM) dose-dependently decreased the calcium response to a pro-inflammatory dose of TRPV4 or TRPA1 agonist (50 μM). In neurons, the calcium response to 25 μM of 4 α PDD or AITC was also significantly reduced with a NaHS pre-treatment (1 mM). Furthermore, IL-8 expression was decreased when NCM460 and Caco-2 cells were pre-treated with NaHS. Conclusions NaHS exposure decreased cellular response to TRPV4 or TRPA1 agonist. Considering the pro-inflammatory and pro-nociceptive effects of TRPV4 or TRPA1 activation in the gut, H 2 S could exert there, anti-inflammatory effects through the inhibition of TRPV4 and TRPA1. Hydrogen sulfide efficiently reduces visceral inflammation and pain as previously demonstrated, our results suggest that these protective effects of H2S donnors could be mediated by TRPV4 and TRPA1 inhibition.

Molecular mechanism of Paclitaxel‐induced degradation of SCG10: a potential neuropathy biomarker (651.14)

Peripheral neuropathy is a major disorder found in diabetic and chemotherapy‐treated cancer patients; it is commonly due to damage to nerve axons. Paclitaxel is a drug used as chemotherapy agent for the treatment of different types of cancer. The mode of action of Paclitaxel is affecting the microtubules’ dynamic instability required for the proper function of neuronal terminals and cell division. Paclitaxel promotes death of rapid dividing cells (i.e. cancer cells) and induces peripheral neuropathy as a side effect. However, the molecular mechanism that mediates Paclitaxel‐induced neuropathy is still unknown. We showed that the abundance of SCG10 ‐ a microtubule destabilizing protein ‐ decreased in Paclitaxel‐treated neuroblastoma cells. SCG10 protein levels are maintained in PC12 cells, when calpain is inhibited, indicating an involvement in the molecular mechanism activated by Paclitaxel‐treatment. In addition, the inhibition of JNKs after mechanical injured Dorsal Ganglion Root neurons blocks the reduction of SCG10 protein. Thus, JNKs may play an important role in Paclitaxel‐induced calpain‐mediated SCG10 protein degradation. Pharmacological and biochemical approaches were used to test this working hypothesis and identified other proteins associated with Paclitaxel‐induced SCG10 protein degradation. The results will contribute to the understanding of the molecular mechanism associated with the cellular respond to Paclitaxel treatment; information that could be used to prevent peripheral neuropathy as a side effect.Grant Funding Source: BP‐ENDURE NeuroID Program (8R25NS080687).

Anatomical study of the roots of cranial parasympathetic ganglia: A contribution to medical education

A major key to increasing the safety of cranial surgery is a thorough understanding of anatomy. The anatomy of the head is of fundamental interest to dental and medical students early in their studies. Clinically, it is mostly relevant to surgeons who are performing interventions and reconstruction in the maxillofacial region, skull base, and the orbit. However, the level of appropriate anatomical knowledge necessary for general and special medical and surgical practice is still under discussion. This study maps the significant areas and structures of the head that are not normally accessible during dissection courses because of time and difficulties involved in the preparation. The detailed photodocumentation enriched by diagrams provides a view of structures until now only partially documented. Three parasympathetic ganglia are located in hardly accessible areas of the head - inside the orbit, infratemporal fossa, and in the pterygopalatine fossa. No detailed photographs have been found in current anatomical textbooks and atlases in relation to the morphology of fibers (roots) connected to the ciliary, otic, and pterygopalatine ganglia. Therefore, this study focused on the detailed display of sensory, sympathetic, and parasympathetic roots of ganglia to provide relevant photodocumentation and an improvement in human anatomy teaching. This study also confirms that cadaver dissection provides an excellent opportunity for the integration of anatomy and clinical medicine into the early clinical training of undergraduate dental and medical students. We believe this article, because of the details mentioned above, will be beneficial not only for the future anatomical undergraduate but also for postgraduate education.

Peripheral choline acetyltransferase in rat skin demonstrated by immunohistochemistry

Conventional choline acetyltransferase immunohistochemistry has been used widely for visualizing central cholinergic neurons and fibers but not often for labeling peripheral structures, probably because of their poor staining. The recent identification of the peripheral type of choline acetyltransferase (pChAT) has enabled the clear immunohistochemical detection of many known peripheral cholinergic elements. Here, we report the presence of pChAT-immunoreactive nerve fibers in rat skin. Intensely stained nerve fibers were distributed in association with eccrine sweat glands, blood vessels, hair follicles and portions just beneath the epidermis. These results suggest that pChAT-positive nerves participate in the sympathetic cholinergic innervation of eccrine sweat glands. Moreover, pChAT also appears to play a role in cutaneous sensory nerve endings. These findings are supported by the presence of many pChAT-positive neuronal cells in the sympathetic ganglion and dorsal root ganglion. Thus, pChAT immunohistochemistry should provide a novel and unique tool for studying cholinergic nerves in the skin.

Disruption of δ-opioid receptor phosphorylation at Threonine 161 attenuates morphine tolerance in rats with CFA-induced inflammatory hypersensitivity

Our previous study identified Threonine 161 (Thr-161), located in the second intracellular loop of the δ-opioid receptor (DOR), as the only consensus phosphorylation site for cyclin-dependent kinase 5 (Cdk5). The aim of this study was to assess the function of DOR phosphorylation by Cdk5 in complete Freund's adjuvant (CFA)-induced inflammatory pain and morphine tolerance. Dorsal root ganglion (DRG) neurons of rats with CFA-induced inflammatory pain were acutely dissociated and the biotinylation method was used to explore the membrane localization of phosphorylated DOR at Thr-161 (pThr-161-DOR), and paw withdrawal latency was measured after intrathecal delivery of drugs or Tat-peptide, using a radiant heat stimulator in rats with CFA-induced inflammatory pain. Both the total amount and the surface localization of pThr-161-DOR were significantly enhanced in the ipsilateral DRG following CFA injection. Intrathecal delivery of the engineered Tat fusion-interefering peptide corresponding to the second intracellular loop of DOR (Tat-DOR-2L) increased inflammatory hypersensitivity, and inhibited DOR- but not µ-opioid receptor-mediated spinal analgesia in CFA-treated rats. However, intrathecal delivery of Tat-DOR-2L postponed morphine antinociceptive tolerance in rats with CFA-induced inflammatory pain. Phosphorylation of DOR at Thr-161 by Cdk5 attenuates hypersensitivity and potentiates morphine tolerance in rats with CFA-induced inflammatory pain, while disruption of the phosphorylation of DOR at Thr-161 attenuates morphine tolerance.

Neural pathways to cardioaccelerator neurons in the isopod crustacean Bathynomus doederleini: Cholinergic activation by somatic movements

We investigated the excitatory and inhibitory input to cardioaccelerator (CA) and cardioinhibitor (CI) neurons located in the thoracic ganglia of the isopod crustacean Bathynomus doederleini by extracellular and intracellular recording. Electrical stimuli applied to the anterior and posterior connectives of single-ganglion preparations, containing either the 2nd or 3rd thoracic ganglion alone, and each of three paired ganglionic nerve roots produced excitatory postsynaptic potentials (EPSPs) in the cell body of a CA neuron. Artificial movements of appendages, such as the thoracic limbs and the swimmerets, also evoked EPSPs in the CA neuron. Electrical stimuli applied to the peripheral nerves running to appendages induced inhibitory postsynaptic potentials (IPSPs) in a CI neuron. Since artificial movements of the appendages caused decrease of CI impulse rate, these IPSPs in the CI neuron may be caused by mechanoproprioceptors in the appendages. Since tachycardia was accompanied by excitation of CA neurons and inhibition of CI neurons, activation of the mechanoproprioceptors may be responsible for tachycardia. EPSPs in CA neurons produced by stimulation of peripheral nerves were augumented by eserinization and blocked by curarization. The activation of CA neurons by ganglionic roots may be mediated by cholinergic processes ascending from mechanoproprioceptors.

The Mrg Family and Pain*

A novel receptor family, the Mas-related G protein-coupled receptors (Mrgs, also called Sensory neuron-specific G protein-coupled receptors or SNSRs), was found in 2001. Interestingly, the mRNAs of Mrgs are expressed predominantly, if not exclusively, in non-overlapping subsets of nonpeptidergic neurons in dorsal root (DRG) and trigeminal ganglia (TG). This specific expression pattern implies significance in physiological and pharmaceutical sciences of pain processing. Study of Mrgs is a new field and will help us to understand the mechanism of pain and nociceptor development. It would also contribute to develop a new analgesic with less central side-effects. The present article summarizes the research progress about Mrgs and provides useful information, such as classification, distribution, expressing regulation and the possible functions in neural circuit and nociception.