Substance P and Glucagon-like Peptide-17-36 Amide Mediate Anorexic Responses to Trichothecene Deoxynivalenol and Its Congeners.

Type B trichothecenes commonly contaminate cereal grains and include five structurally related congeners: deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), fusarenon X (FX), and nivalenol (NIV). These toxins are known to have negative effects on human and animal health, particularly affecting food intake. However, the pathophysiological basis for anorexic effect is not fully clarified. The purpose of this study is to explore the potential roles of the brain-gut peptides substance P (SP) and glucagon-like peptide-17-36 amide (GLP-1) in anorexic responses induced by type B trichothecenes following both intraperitoneal (IP) and oral administration. SP and GLP-1 were elevated at 1 or 2 h and returned to basal levels at 6 h following exposure to DON and both ADONs. FX induced the production of both brain gut peptides with initial time at 1 or 2 h and duration > 6 h. Similar to FX, exposing IP to NIV caused elevations of SP and GLP-1 at 1 h and lasted more than 6 h, whereas oral exposure to NIV only increased both brain gut peptides at 2 h. The neurokinin-1 receptor (NK-1R) antagonist Emend® dose-dependently attenuated both SP- and DON-induced anorexic responses. Pretreatment with the GLP-1 receptor (GLP-1R) antagonist Exending9-39 induced a dose-dependent attenuation of both GLP-1- and DON-induced anorexic responses. To summarize, the results suggest that both SP and GLP-1 play important roles in anorexia induction by type B trichothecenes.

Protective effects of dihydromyricetin on primary hippocampal astrocytes from cytotoxicity induced by comorbid diabetic neuropathic pain and depression.

Activated astrocytes play a key role in diabetic neuropathic pain and depression. We aimed to assess the protective effects of dihydromyricetin (DHM) on primary hippocampal astrocytes cultured with high glucose (HG), substance P (SP), and corticosterone (CORT). Culturing with HG + SP + CORT resulted in damage to primary hippocampal astrocytes, which simulates the clinical damage caused by comorbidity of diabetic neuropathic pain and depression. Western blot, qPCR, and immunofluorescence analyses revealed that HG + SP + CORT increased P2X7 receptor expression in primary hippocampal astrocytes, which was reversed by DHM treatment. Further, HG + SP + CORT elevated TNF-α, IL-1ß, free Ca2+, and ERK1/2 phosphorylation levels, which was inhibited by DHM or P2X7 shRNA treatment. Moreover, DHM significantly reduced the P2X7 agonist-activated currents in HEK293 cells transfected with the P2X7 receptor. These findings suggest that DHM can protect primary hippocampal astrocytes cultured with HG + SP + CORT from P2X7 receptor-mediated damage. Culturing cells with HG + SP + CORT might be a viable cell model for cellular injury exploration of diabetic comorbid pain and depression.

Targeted hippocampal GABA neuron ablation by Stable Substance P-saporin causes hippocampal sclerosis and chronic epilepsy in rats.

Cryptogenic temporal lobe epilepsy develops in the absence of identified brain injuries, infections, or structural malformations, and in these cases, an unidentified pre-existing abnormality may initiate febrile seizures, hippocampal sclerosis, and epilepsy. Although a role for GABAergic dysfunction in epilepsy is intuitively obvious, no causal relationship has been established. In this study, hippocampal GABA neurons were targeted for selective elimination to determine whether a focal hippocampal GABAergic defect in an otherwise normal brain can initiate cryptogenic temporal lobe epilepsy with hippocampal sclerosis. We used Stable Substance P-saporin conjugate (SSP-saporin) to target rat hippocampal GABA neurons, which selectively and constitutively express the neurokinin-1 receptors that internalize this neurotoxin. Bilateral and longitudinally extensive intrahippocampal microinjections of SSP-saporin caused no obvious behavioral effects for several days. However, starting ~4 days postinjection, rats exhibited episodes of immobilization, abnormal flurries of "wet-dog" shakes, and brief focal motor seizures characterized by facial automatisms and forepaw clonus. These clinically subtle behaviors stopped after ~4 days. Convulsive status epilepticus did not develop, and no deaths occurred. Months later, chronically implanted rats exhibited spontaneous focal motor seizures and extreme hippocampal sclerosis. These data suggest that hippocampal GABAergic dysfunction is epileptogenic and can produce the defining features of cryptogenic temporal lobe epilepsy.

Involvement of the cystathionine-γ-lyase/Cav3.2 pathway in substance P-induced bladder pain in the mouse, a model for nonulcerative bladder pain syndrome.

Hydrogen sulfide (H2S) formed by cystathionine-γ-lyase (CSE) enhances the activity of Cav3.2 T-type Ca2+ channels, contributing to the bladder pain accompanying hemorrhagic cystitis caused by systemic administration of cyclophosphamide (CPA) in mice. Given clinical and fundamental evidence for the involvement of the substance P/NK1 receptor systems in bladder pain syndrome (BPS)/interstitial cystitis (IC), we created an intravesical substance P-induced bladder pain model in mice and analyzed the possible involvement of the CSE/Cav3.2 pathway. Bladder pain/cystitis was induced by i.p. CPA or intravesical substance P in female mice. Bladder pain was evaluated by counting nociceptive behavior and by detecting referred hyperalgesia in the lower abdomen and hindpaw. The isolated bladder tissue was weighed to estimate bladder swelling and subjected to histological observation and Western blotting. Intravesical substance P caused profound referred hyperalgesia accompanied by little bladder swelling or edema 6-24 h after the administration, in contrast to i.p. CPA-induced nociceptive behavior/referred hyperalgesia with remarkable bladder swelling/edema and urothelial damage. The bladder pain and/or cystitis symptoms caused by substance P or CPA were prevented by the NK1 receptor antagonist. CSE in the bladder was upregulated by substance P or CPA, and the NK1 antagonist prevented the CPA-induced CSE upregulation. A CSE inhibitor, a T-type Ca2+ channel blocker and gene silencing of Cav3.2 abolished the intravesical substance P-induced referred hyperalgesia. The intravesical substance P-induced pain in mice is useful as a model for nonulcerative BPS, and involves the activation of the NK1 receptor/CSE/H2S/Cav3.2 cascade.

Substance P promotes hepatic stellate cell proliferation and activation via the TGF-ß1/Smad-3 signaling pathway.

Prolonged activation and proliferation of hepatic stellate cells (HSCs) usually results in the initiation and progression of liver fibrosis following injury. Recent studies have shown that Substance P (SP) participates in the development of fibrosis. However, whether SP is involved in liver fibrosis, especially in the activation and proliferation of HSCs, is largely unknown. In the present study, we measured the effects of a series of concentrations of SP on the cell viability and activation of HSC-T6 cells and LX2 cells. The underlying mechanism was also investigated. We found that SP effectively increased cell viability, both in an MTT assay (p<0.05) and in a lactate dehydrogenase activity assay (LDH) (p<0.05). Moreover, SP upregulated the protein expression of α-SMA and Collagen I (both p<0.05) and decreased the release of lipid droplets (LDs) (p<0.05), all of which are associated with HSC activation. Apoptosis analysis revealed that SP can attenuate the increase of cell apoptosis induced by serum withdrawal (p<0.05). Furthermore, these effects were all blocked by an SP receptor antagonist, L732138. More importantly, L732138 decreased the activation of the TGF-ß1/Smad3 signaling pathway, which is highly associated with liver fibrosis. Taken together, our results demonstrate that SP can promote HSC proliferation and induce HSC activation via the TGF-ß1/Smad3 signaling pathway.

Intrathecal substance P-saporin in the dog: distribution, safety, and spinal neurokinin-1 receptor ablation.

BACKGROUND: Neurokinin-1 receptors (NK1-rs) located on superficial dorsal horn neurons are essential for integration of nociceptive input. Intrathecal injection of substance P-saporin (SP-SAP) leads to local loss of spinal NK1-r (+) neurons suggesting its potential as a therapeutic agent for chronic pain. The authors determined, in a canine model, effects of lumbar intrathecal SP-SAP. METHODS: Distribution of SP-SAP and Saporin was determined in plasma, lumbar cerebrospinal fluid, and tissue. Safety of intrathecal SP-SAP was determined in four groups (six dogs each) administered 0 (0.9% saline), 1.5, 15, or 150 µg SP-SAP through lumbar intrathecal catheters. Behavioral, physiologic, and biochemical variables were assessed. Spinal tissues were collected at 7 and approximately 90 days, or earlier if significant morbidity developed, and analyzed for NK1-r (+) neuron loss and histopathology. RESULTS: SP-SAP and Saporin were detectable in lumbar cerebrospinal fluid for up to 4 and 24 h, respectively. Animals receiving intrathecal saline, 1.5, or 15 µg of SP-SAP showed no persistent neurologic deficits. Three animals receiving 150 µg of SP-SAP developed pelvic limb paraparesis and were euthanized prematurely. Immunohistochemistry and in situ hybridization cell counts confirmed a significant reduction in NK1-r (+) in superficial dorsal horn neurons from lumbar spinal cord after intrathecal administration of 15 and 150 µg of SP-SAP. A significant loss of NK1-r neurons in the lumbar ventral horn occurred only with 150-µg SP-SAP. CONCLUSION: Intrathecal 15-µg SP-SAP reduced dorsal, but not ventral, NK1-r (+) neurons at the spinal level of delivery with minimal side effects, whereas 150-µg SP-SAP resulted in motor neuron toxicity.

Chronic peripheral administration of kappa-opioid receptor antagonist advances puberty onset associated with acceleration of pulsatile luteinizing hormone secretion in female rats.

Puberty in mammals is timed by an increase in gonadotropin-releasing hormone (GnRH) secretion. Previous studies have shown involvement of the two neuropeptides, kisspeptin and neurokinin B (NKB), in controlling puberty onset. Little is known about the role of the other key neuropeptide, dynorphin, in controlling puberty onset, although these three neuropeptides colocalize in the arcuate kisspeptin neurons. The arcuate kisspeptin neuron, which is also referred to as the KNDy neuron, has recently been considered to play a role as an intrinsic source of the GnRH pulse generator. The present study aimed to determine if attenuation of inhibitory dynorphin-kappa-opioid receptor (KOR) signaling triggers the initiation of puberty in normal developing female rats. The present study also determined if stimulatory NKB-neurokinin 3 receptor (NK3R) signaling advances puberty onset. Female Wistar-Imamichi rats were weaned and intraperitoneally implanted with osmotic minipumps filled with nor-binaltorphimine (nor-BNI), a KOR antagonist, or senktide, a NK3R agonist, at 20 days of age. Fourteen days of intraperitoneal infusion of nor-BNI or senktide advanced puberty onset, manifested as vaginal opening and the first vaginal estrus in female rats. Frequent blood sampling showed that nor-BNI significantly increased luteinizing hormone (LH) pulse frequency at 29 days of age compared with vehicle-treated controls. Senktide tended to increase this frequency, but its effect was not statistically significant. The present results suggest that the inhibitory input of dynorphin-KOR signaling plays a role in the prepubertal restraint of GnRH/LH secretion in normal developing female rats and that attenuation of dynorphin-KOR signaling and increase in NKB-NK3R signaling trigger the onset of puberty in female rats.

Keratinocyte expression of inflammatory mediators plays a crucial role in substance P-induced acute and chronic pain.

Tibia fracture in rats followed by cast immobilization leads to nociceptive, trophic, vascular and bone-related changes similar to those seen in Complex Regional Pain Syndrome (CRPS). Substance P (SP) mediated neurogenic inflammation may be responsible for some of the signs of CRPS in humans. We therefore hypothesized that SP acting through the SP receptor (NK1) leads to the CRPS-like changes found in the rat model. In the present study, we intradermally injected rats with SP and monitored hindpaw mechanical allodynia, temperature, and thickness as well as tissue levels of tumor necrosis factor-α (TNF-α), interleukin 1ß (IL-1ß), interleukin 6 (IL-6), and nerve growth factor-ß (NGF) for 72 h. Anti-NGF antibody was utilized to block the effects of SP-induced NGF up-regulation. Fracture rats treated with the selective NK1 receptor antagonist LY303870 prior to cast removal were assessed for BrdU, a DNA synthesis marker, incorporation in skin cells to examine cellular proliferation. Bone microarchitecture was measured using micro computed tomography (µCT). We observed that: (1) SP intraplantar injection induced mechanical allodynia, warmth and edema as well as the expression of nociceptive mediators in the hindpaw skin of normal rats, (2) LY303870 administered intraperitoneally after fracture attenuated allodynia, hindpaw unweighting, warmth, and edema, as well as cytokine and NGF expression, (3) LY303870 blocked fracture-induced epidermal thickening and BrdU incorporation after fracture, (4) anti-NGF antibody blocked SP-induced allodynia but not warmth or edema, and (5) LY303870 had no effect on bone microarchitecture. Collectively our data indicate that SP acting through NK1 receptors supports the nociceptive and vascular components of CRPS, but not the bone-related changes.

Ventilatory effects of substance P-saporin lesions in the nucleus tractus solitarii of chronically hypoxic rats.

During ventilatory acclimatization to hypoxia (VAH), time-dependent increases in ventilation lower Pco(2) levels, and this persists on return to normoxia. We hypothesized that plasticity in the caudal nucleus tractus solitarii (NTS) contributes to VAH, as the NTS receives the first synapse from the carotid body chemoreceptor afferents and also contains CO(2)-sensitive neurons. We lesioned cells in the caudal NTS containing the neurokinin-1 receptor by microinjecting the neurotoxin saporin conjugated to substance P and measured ventilatory responses in awake, unrestrained rats 18 days later. Lesions did not affect hypoxic or hypercapnic ventilatory responses in normoxic control rats, in contrast to published reports for similar lesions in other central chemosensitive areas. Also, lesions did not affect the hypercapnic ventilatory response in chronically hypoxic rats (inspired Po(2) = 90 Torr for 7 days). These results suggest functional differences between central chemoreceptor sites. However, lesions significantly increased ventilation in normoxia or acute hypoxia in chronically hypoxic rats. Hence, chronic hypoxia increases an inhibitory effect of neurokinin-1 receptor neurons in the NTS on ventilatory drive, indicating that these neurons contribute to plasticity during chronic hypoxia, although such plasticity does not explain VAH.

Lactobacillus paracasei CNCM I-2116 (ST11) inhibits substance P-induced skin inflammation and accelerates skin barrier function recovery in vitro.

Over the past few decades the number of people presenting reactive skin has increased in industrial countries. Skin inflammation mediated by neuropeptides and impaired skin barrier function are both underlying features of reactive skin conditions. Live microorganisms defined as probiotics have been successfully used to improve health status in humans. Beyond the effects on intestinal microbiota, some probiotic strains display potent immune-modulatory properties at the skin level. The aim of this study was to evaluate whether Lactobacillus paracasei CNCM-I 2116 (ST11) could modulate reactive skin-associated inflammatory mechanisms. The Caco-2/PBMC co-culture cell system was stimulated on the apical side with probiotics. The resulting medium collected from the basolateral compartment of the cell culture system, so called conditioned medium, was tested in ex vivo human abdominal plastic skin explant models of substance P-induced skin inflammation and skin barrier reconstruction. We show that ST11 was able to abrogate vasodilation, edema, mast cell degranulation and TNF-alpha release induced by substance P, compared to control. Moreover, using ex vivo skin organ culture, we show that ST11-conditioned medium induced a significantly faster barrier function recovery after SLS disruption, compared to control. These results support a beneficial role of ST11 on key biological processes associated with barrier function and skin reactivity.

Warm SPA-induced hyperthermia confers protection to rats against airway inflammation evoked by capsaicin and substance P.

Solus par aqua (SPA) is a traditional health care therapy. Warm SPA may enhance immunity and cellular defense to protect body against diseases. The present study investigated whether the warm SPA could confer protection to neurogenic inflammation in rats. The rats were immersed in water where the body core temperatures were maintained at hyperthermia (41.5 degrees C) or normothermia (37 degrees C) for a period of 15min. After SPA for 1 or 6 days, neurogenic inflammation was induced by intravenous injection of capsaicin (90microg/kg) or substance P (SP; 3microg/kg). The plasma leakage and arterial pressures in rats after neurogenic inflammation were monitored. The extent of capsaicin- or SP-induced plasma leakage and hypotension was significantly attenuated in rats on day 1 after SPA hyperthermia. However, such resistance to neurogenic inflammation was not found on day 6 after hyperthermia. Western blotting analysis showed that the expression of heat shock protein 72 (HSP 72) in the trachea on days 1 and 2 after hyperthermia was 9.61-fold and 6.66-fold, respectively, of that in normothermia. Afterwards, the hyperthermia-induced HSP 72 upregulation gradually declined in a time-dependent manner. Thus, SPA hyperthermia may protect rats against neurogenic inflammation through modulation of HSP expression.

Ablation of least shrew central neurokinin NK1 receptors reduces GR73632-induced vomiting.

The neurocircuitry mediating the emetic reflex is still incompletely understood, and a key question is the degree to which central and/or peripheral components contribute to the overall vomiting mechanism. Having previously found a significant peripheral component in neurokinin NK-receptor mediated emesis, the authors undertook this study to examine the putative central component. Adult least shrews were injected intracerebroventricularly (icv) with saline or the blood-brain barrier impermeable toxin, stable substance P-saporin (SSP-SAP), which ablates cells expressing NK receptors. After 3 days, shrews were challenged intraperitoneally with the emetogenic NK agonist GR73632 at different doses, and vomiting and scratching behaviors were quantified. Ablation of NK1-bearing cells was verified immunohistochemically. Although SSP-SAP injection reduced emesis at GR73632 doses of 2.5 and 5 mg/kg, no injections completely eliminated emesis. These data demonstrate that there is both a major central nervous system component and a minor peripheral nervous system component to tachykinin-mediated vomiting. Side effects of the current generation of antiemetics could potentially be reduced by improving bioavailability of the drugs in the more potent central nervous system compartment while reducing bioavailability in the less potent peripheral compartment.

Investigation of the pruritogenic effects of histamine, serotonin, tryptase, substance P and interleukin-2 in healthy dogs.

There are numerous studies of the pruritus-producing effects of histamine, serotonin, tryptase, substance P and interleukin-2 in humans and mice, but very little reported in dogs even though a common reason dogs are presented to veterinarians is pruritus. The aim of this study was to determine whether substances known to cause pruritus in humans also cause pruritus in dogs. Twenty-five clinically healthy research beagle dogs were included in the study. All dogs first received an intradermal injection of 0.05 mL saline as a control substance and were video-recorded for 20 min before and after the injection. Twenty-four hours later the dogs were randomly divided into five groups of five dogs each and randomly assigned to receive histamine, serotonin, tryptase, substance P or interleukin-2 injected intradermally each at the volume of 0.05 mL. On subsequent days, increasing concentrations of each substance were used. Before (baseline) and after the injection of each concentration of the substances, the dogs were video-recorded for 20 min. The frequency and character of pruritus episodes (scratching, licking, chewing, rubbing or rolling) were noted and these data were used for statistical analysis. The number of pruritus episodes was compared among baseline, saline and the different concentrations of each substance. The results showed that dogs did not have a significant increase in pruritic behaviour above baseline or saline after injection of any of the investigated substances (generalized linear model; P = 0.23).

Acetaminophen prevents hyperalgesia in central pain cascade.

Acetaminophen is an analgesic and antipyretic drug believed to exert its effect through interruption of nociceptive processing. In order to determine whether this effect is due to peripheral or central activity, we studied the efficacy of systemic (oral) and intrathecal (IT) application of acetaminophen in preventing the development of hyperalgesia induced through the direct activation of pro-algogenic spinal receptors. Spinal administration of substance P (SP, 30 nmol, IT) in rats produced a decreased thermal threshold, indicating centrally mediated hyperalgesia. Pretreatment of rats with oral acetaminophen (300 mg/kg), but not vehicle, significantly attenuated IT SP-induced hyperalgesia. Acetaminophen given IT also produced a dose-dependent (10-200 microg) antinociceptive effect. In addition, oral acetaminophen suppressed spinal PGE(2) release evoked by IT SP in an in vivo IT dialysis model. The ability of IT as well as oral acetaminophen to reverse this spinally initiated hyperalgesia emphasizes the likely central action and bioavailability of the systemically delivered drug. Jointly, these data argue for an important central antihyperalgesic action of acetaminophen.

Elimination of rat spinal substance P receptor bearing neurons dissociates cardiovascular and nocifensive responses to nicotinic agonists.

Intrathecal (IT) delivery of nicotinic agonists evokes dose dependent nocifensive behavior and cardiovascular responses. Previous studies suggested that these effects may be attenuated by the loss of substance P positive (sP(+)) primary afferents. To further characterize these cell systems, we examined the effect of selectively destroying neurokinin 1 receptor bearing (NK1-r(+)) dorsal horn neurons on IT nicotinic agonist evoked responses. In the dorsal spinal cord, confocal immunohistochemical microscopy revealed that nAChR subunits (alpha3, alpha4, alpha5, beta2 and beta4), NeuN B (neuronal marker) and NK1-r were all co-expressed in the superficial dorsal horn; however alpha3, alpha5, beta2 and beta4 exhibited the highest degree of colocalization with NK1-r expressing neurons. After intrathecal substance P-saporin (sP-SAP), NK1-r(+) cell bodies and dendrites in the superficial dorsal horn were largely abolished. The greatest loss in co-expression of nAChR subunits with NK1-r was observed with alpha3, alpha5, beta2 and beta4 subunits. Following intrathecal sP-SAP, the nocifensive responses to all nicotinic agonists were reduced; however, in contrast, while cardiovascular responses evoked by IT nicotine were unaltered, IT cytisine and epibatidine exhibited enhanced tachycardia and pressor responses. These results indicate subunit-specific relationships between the NK1-r and nicotinic receptor systems. The loss of nocifensive activity after destruction of the NK1-r bearing cells in spite of the persistence of nicotinic subunits on other cells, emphasizes the importance of the superficial marginal neuron in mediating these nicotinic effects. Further, the exaggerated cardiovascular responses to cytisine following loss of NK1-r bearing cells suggest the presence of a nicotinic receptor-mediated stimulation of inhibitory circuits at the spinal level.

Roles of TRPV1 and neuropeptidergic receptors in dorsal root reflex-mediated neurogenic inflammation induced by intradermal injection of capsaicin.

BACKGROUND: Acute cutaneous neurogenic inflammation initiated by activation of transient receptor potential vanilloid-1 (TRPV1) receptors following intradermal injection of capsaicin is mediated mainly by dorsal root reflexes (DRRs). Inflammatory neuropeptides are suggested to be released from primary afferent nociceptors participating in inflammation. However, no direct evidence demonstrates that the release of inflammatory substances is due to the triggering of DRRs and how activation of TRPV1 receptors initiates neurogenic inflammation via triggering DRRs. RESULTS: Here we used pharmacological manipulations to analyze the roles of TRPV1 and neuropeptidergic receptors in the DRR-mediated neurogenic inflammation induced by intradermal injection of capsaicin. The degree of cutaneous inflammation in the hindpaw that followed capsaicin injection was assessed by measurements of local blood flow (vasodilation) and paw-thickness (edema) of the foot skin in anesthetized rats. Local injection of capsaicin, calcitonin gene-related peptide (CGRP) or substance P (SP) resulted in cutaneous vasodilation and edema. Removal of DRRs by either spinal dorsal rhizotomy or intrathecal administration of the GABAA receptor antagonist, bicuculline, reduced dramatically the capsaicin-induced vasodilation and edema. In contrast, CGRP- or SP-induced inflammation was not significantly affected after DRR removal. Dose-response analysis of the antagonistic effect of the TRPV1 receptor antagonist, capsazepine administered peripherally, shows that the capsaicin-evoked inflammation was inhibited in a dose-dependent manner, and nearly completely abolished by capsazepine at doses between 30-150 mug. In contrast, pretreatment of the periphery with different doses of CGRP8-37 (a CGRP receptor antagonist) or spantide I (a neurokinin 1 receptor antagonist) only reduced the inflammation. If both CGRP and NK1 receptors were blocked by co-administration of CGRP8-37 and spantide I, a stronger reduction in the capsaicin-initiated inflammation was produced. CONCLUSION: Our data suggest that 1) the generation of DRRs is critical for driving the release of neuropeptides antidromically from primary afferent nociceptors; 2) activation of TRPV1 receptors in primary afferent nociceptors following intradermal capsaicin injection initiates this process; 3) the released CGRP and SP participate in neurogenic inflammation.

Anti-inflammatory evaluation of Solidago chilensis Meyen in a murine model of pleurisy.

UNLABELLED: The aim of this study was to investigate the anti-inflammatory effects and the mechanism of action of the aqueous extracts obtained from rhizomes, leaves and inflorescences of Solidago chilensis in the mouse model of pleurisy. The extracts were prepared by infusion and were lyophilized. RESULTS: The aqueous extracts of rhizomes, leaves or inflorescences inhibited leukocytes, neutrophils and exudation (P<0.05) in the inflammation induced by carrageenan. The rhizomes aqueous extract, butanolic and aqueous residual fractions inhibited leukocytes, neutrophils, myeloperoxidase, adenosine-deaminase, and tumor necrosis factor alpha levels in the inflammation induced by carrageenan (P<0.05). The rhizome aqueous extract and butanolic fraction also inhibited exudation, nitric oxide, and interleukin-1 beta levels (P<0.05). The rhizomes aqueous extract and its two derived fractions reduced leukocytes and mononuclears in the pleurisy induced by bradykinin, histamine, or substance P (P<0.05) and neutrophils in the pleurisy induced by histamine or substance P (P<0.05). Only aqueous residual fraction inhibited neutrophils induced by bradykinin (P<0.05). CONCLUSION: Solidago chilensis aqueous extracts from leaves, inflorescences and rhizomes demonstrated an important anti-inflammatory effect, inhibiting cells in the inflammation caused by carrageenan. In addition, the rhizomes aqueous extract and its derived fractions also decreased pro-inflammatory mediators release into the site of the inflammatory process. The rhizomes aqueous extract and the butanolic fraction showed more evident anti-inflammatory actions.

Superficial NK1 expressing spinal dorsal horn neurones modulate inhibitory neurotransmission mediated by spinal GABA(A) receptors.

Lamina 1 projection neurones which express the NK1 receptor (NK1R+) drive a descending serotonergic pathway from the brainstem that enhances spinal dorsal horn neuronal activity via the facilitatory spinal 5-HT3 receptor. Selective destruction of these cells via lumbar injection of substance P-saporin (SP-SAP) attenuates pain behaviours, including mechanical and thermal hypersensitivity, which are mirrored by deficits in the evoked responses of lamina V-VI wide dynamic range (WDR) neurones to noxious stimuli. To assess whether removing the origin of this facilitatory spino-bulbo-spinal loop results in alterations in GABAergic spinal inhibitory systems, the effects of spinal bicuculline, a selective GABA(A) receptor antagonist, on the evoked neuronal responses to electrical (Abeta-, Adelta-, C-fibre, post-discharge and Input) and mechanical (brush, prod and von Frey (vF) 8 and 26 g) stimuli were measured in SAP and SP-SAP groups. In the SAP control group, bicuculline produced a significant dose related facilitation of the electrically evoked Adelta-, C-fibre, post-discharge and input neuronal responses. The evoked mechanical (prod, vF8 g and 26 g) responses were also significantly increased. Brush evoked neuronal responses in these animals were enhanced but did not reach significance. This facilitatory effect of bicuculline, however, was lost in the SP-SAP treated group. The generation of intrinsic GABAergic transmission in the spinal cord appears dependent on NK1 bearing neurons, yet despite the loss of GABAergic inhibitory controls after SP-SAP treatment, the net effect is a decrease in spinal cord excitability. Thus activation of these cells predominantly drives facilitation.

Suppression by bepotastine besilate of substance P-induced itch-associated responses through the inhibition of the leukotriene B4 action in mice.

Anti-pruritic effects of the antihistamine bepotastine besilate were studied in mice. Bepotastine besilate (10 mg/kg) inhibited scratching induced by an intradermal injection of histamine (100 nmol/site), but not serotonin (100 nmol/site). Bepotastine besilate (1-10 mg/kg, oral) dose-dependently suppressed scratching induced by substance P (100 nmol/site) and leukotriene B(4) (0.03 nmol/site). An intradermal injection of substance P (100 nmol/site) increased the cutaneous concentration of leukotriene B(4), which was not affected by bepotastine besilate (10 mg/kg, oral). Leukotriene B(4) increased Ca(2+) concentration in cultured neutrophils, which was suppressed by bepotastine besilate (1-100 microM). Leukotriene B(4) increased Ca(2+) concentration in cultured dorsal root ganglion neurons, which was also suppressed by bepotastine besilate (100 microM). The results suggest that the inhibition of the actions of leukotriene B(4) as well as histamine is involved in the anti-pruritic effect of bepotastine besilate.