Influence of the polymorphism of the DUSP14 gene on the expression of immune-related genes and development of pulmonary tuberculosis.

Recently, a genome-wide screening identified a functional single-nucleotide polymorphism in dual-specificity phosphatase 14 gene (DUSP14), which was associated with pulmonary tuberculosis (TB) in a West African study. DUSP14 regulates T-cell proliferation and cytokine production in a negative way via dephosphorylation and inactivation of key signaling molecules. The aim of this study is to further explore the possible significance of the DUSP14 polymorphism. Total RNA was extracted from the whole blood of 109 healthcare workers (HCWs) in Vietnam and subjected to quantitative reverse-transcription PCR for DUSP14 and 20 immune-related genes. DUSP14 rs1051838 was genotyped in 502 new pulmonary TB patients and 506 healthy controls. Among disease-free individuals (HCWs), T-helper type-1 (Th1)-related genes, interferon-gamma receptor 2 (IFNGR2) and signal transducer and activator of transcription-1 (STAT1) mRNA levels significantly increased as the number of A alleles of rs1051838 increased, whereas the DUSP14 mRNA level tended to decrease. The AA genotype was associated with protection against active TB in younger patients (⩽45 years old, OR=0.63, 95% CI 0.44-0.90). Our results suggest that a low-expression genotype of DUSP14 accompanied by high transcript levels of Th1 immune-related genes may confer protection against early TB development.

Enteric opportunistic parasitic infections among HIV seropositive patients in Kathmandu, Nepal.

BACKGROUND: Enteric opportunistic parasitic infections are the major source of diarrheal disease in developing countries mainly in Human Immunodeficiency virus (HIV) infected patients. OBJECTIVE: The study was to detect enteric parasites causing diarrhea and their association with immune status in HIV-seropositive patients. METHODS: The present study was conducted in Dirgh-Jeevan Health Care Research Center and Tribhuvan University Teaching Hospital, Public Health Research Laboratory, Kathmandu, Nepal between June 2010 and May 2011 involving 146 Human Immunodeficiency virus (HIV) positive patients. Serostatus from these patients were detected by Enzyme Linked Immunosorbent assay. CD4+ T cell counts were done by flow cytometry. Stool was examined for enteric parasites by microscopy with special staining methods. RESULTS: A total of 146 HIV sero-positive patients with and without diarrhea age between 20 to 45 years were included in the study. Of the 146 patients, the protozoan parasitic infection was found in 30.13% (44/146). Out of 146 patients, 78 had diarrhea in which parasitic infection was 39 (50%) and 7.35% (5/68) protozoal parasites positive cases did not have diarrhea. A significant difference (p less than 0.05) was observed in the level of infection of intestinal protozoan between the HIV seropositive with diarrhea and HIV-seropositive without diarrhea. Out of 43 patients whose CD4+ T cells were less than 200/µl, 29 (67.4%) had opportunistic parasitic infection whereas out of 103 patients whose CD4+ T cells were =200/mcl, only 15 (14.56%) had opportunistic parasitic infection (P less than 0.05). CONCLUSION: Enteric opportunistic parasitic infections were detected in 30.1% among HIV-seropositive patients and low CD4+ T count indicated high enteric opportunistic infection. Early detection of enteric parasitic infections will help in the management and to improve the quality of life for HIV-infected individuals.

Is there a rational basis for cannabinoids research and development in ocular pain therapy? A systematic review of preclinical evidence.

BACKGROUND: Purpose of the present systematic review is to investigate preclinical evidence in favor of the working hypothesis of efficacy of cannabinoids in ocular pain treatment. METHODS: Literature search includes the most relevant repositories for medical scientific literature from inception until November, 24 2021. Data collection and selection of retrieved records adhere to PRISMA criteria. RESULTS: In agreement with a priori established protocol the search retrieved 2471 records leaving 479 results after duplicates removal. Eleven records result from title and abstract screening to meet the inclusion criteria; only 4 results are eligible for inclusion in the qualitative synthesis impeding meta-analysis. The qualitative analysis highlights the antinociceptive and anti-inflammatory efficacy of Δ8-tetrahydrocannabinol, cannabidiol and its derivative HU-308 and of new racemic CB1 allosteric ligand GAT211 and its enantiomers GAT228 and GAT229. Moreover, CB2R agonists RO6871304 and RO6871085 and CB2R ligand HU910 provide evidence of anti-inflammatory efficacy. CB2 agonist HU308 reduces of 241% uveitis-induced leukocyte adhesion and changes lipidome profile. Methodological and design issues raise concern of risk of bias and the amount of studies is too small for generalization. Furthermore, the ocular pain model used can resemble only inflammatory but not neuropathic pain. CONCLUSIONS: The role of the endocannabinoid system in ocular pain is underinvestigated, since only two studies assessing the effects of cannabinoid receptors modulators on pain behavior and other two on pain-related inflammatory processes are found. Preclinical studies investigating the efficacy of cannabinoids in ocular inflammatory and neuropathic pain models are needed to pave the way for clinical translation.

Inhibition of development of Kaposi's sarcoma-related lesions by a bacterial cell wall complex.

In vitro and in vivo model systems for the study of human immunodeficiency virus (HIV)-associated Kaposi's sarcoma (KS) were used to evaluate compounds for their potential as therapeutic agents. A sulfated polysaccharide-peptidoglycan compound (SP-PG) produced by bacteria controlled the in vitro growth of acquired immunodeficiency syndrome (AIDS)-associated, KS-derived spindle-shaped cells (AIDS-KS cells) at noncytotoxic concentrations. Angiogenesis induced by AIDS-KS cells in the chicken chorioallantoic membrane assay was blocked by SP-PG, which also inhibited the vascular hyperpermeability response and the angiogenesis associated with the induction of KS-like lesions that develop after subcutaneous inoculation of AIDS-KS cells into nude mice. Suramin, pentosan polysulfate, and interferon alpha, which are currently in use for therapy of KS, were either less effective than SP-PG or much more cytotoxic, or both.

A survey of tuberculosis prevalence in Hanoi, Vietnam.

OBJECTIVE: To assess the prevalence of tuberculosis (TB) in Hanoi, Vietnam, in 2003/2004. METHODS: A random selection was carried out involving 11624 subjects from 20 communes within the city. RESULTS: On chest X-ray examination, 317 subjects (2.73%) showed abnormal lung opacity, of which 17 were sputum smear-positive, two concentrated smear-positive and three culture-positive, all with active TB. The prevalence of sputum smear-positive pulmonary TB was 146 per 100000 in persons aged >or=15 years (95%CI 65-228). CONCLUSION: This is the first large-scale assessment of the prevalence of TB in Hanoi. The prevalence rate was higher than expected, suggesting that a significant number of patients with active TB, particularly females, remain undiagnosed, thus representing a continuing potential source of transmission in the community.

Inhibitory regulation of Rac activation, membrane ruffling, and cell migration by the G protein-coupled sphingosine-1-phosphate receptor EDG5 but not EDG1 or EDG3.

Sphingosine-1-phosphate (S1P) is a bioactive lysophospholipid that induces a variety of biological responses in diverse cell types. Many, if not all, of these responses are mediated by members of the EDG (endothelial differentiation gene) family G protein-coupled receptors EDG1, EDG3, and EDG5 (AGR16). Among prominent activities of S1P is the regulation of cell motility; S1P stimulates or inhibits cell motility depending on cell types. In the present study, we provide evidence for EDG subtype-specific, contrasting regulation of cell motility and cellular Rac activity. In CHO cells expressing EDG1 or EDG3 (EDG1 cells or EDG3 cells, respectively) S1P as well as insulin-like growth factor I (IGF I) induced chemotaxis and membrane ruffling in phosphoinositide (PI) 3-kinase- and Rac-dependent manners. Both S1P and IGF I induced a biphasic increase in the amount of the GTP-bound active form of Rac. In CHO cells expressing EDG5 (EDG5 cells), IGF I similarly stimulated cell migration; however, in contrast to what was found for EDG1 and EDG3 cells, S1P did not stimulate migration but totally abolished IGF I-directed chemotaxis and membrane ruffling, in a manner dependent on a concentration gradient of S1P. In EDG5 cells, S1P stimulated PI 3-kinase activity as it did in EDG1 cells but inhibited the basal Rac activity and totally abolished IGF I-induced Rac activation, which involved stimulation of Rac-GTPase-activating protein activity rather than inhibition of Rac-guanine nucleotide exchange activity. S1P induced comparable increases in the amounts of GTP-RhoA in EDG3 and EDG5 cells. Neither S1P nor IGF I increased the amount of GTP-bound Cdc42. However, expression of N(17)-Cdc42, but not N(19)-RhoA, suppressed S1P- and IGF I-directed chemotaxis, suggesting a requirement for basal Cdc42 activity for chemotaxis. Taken together, the present results demonstrate that EDG5 is the first example of a hitherto-unrecognized type of receptors that negatively regulate Rac activity, thereby inhibiting cell migration and membrane ruffling.

Effects of anti-nuclear factor kappa B reagents in blocking adhesion of human cancer cells to vascular endothelial cells.

Transcription factor nuclear factor kappa B (NF kappa B) controls gene expression of a number of genes including cell adhesion molecules such as E-selectin, intercellular adhesion molecule 1, and vascular adhesion molecule 1. These cell adhesion molecules are known to play important roles in a critical step of tumor metastasis, arrest of tumor cells onto the venous or capillary bed of the target organ. NF kappa B is activated by extracellular signals such as those elicited by proinflammatory cytokines, tumor necrosis factor and interleukin 1 (IL-1). Here we demonstrate that IL-1 beta induces nuclear translocation of NF kappa B in human umbilical vein endothelial cells, followed by induction of cell surface expression of E-selectin, intercellular adhesion molecule-1, and vascular adhesion molecule 1, and subsequently augments adhesion of those cancer cells expressing sialyl Lewis X antigen, a ligand to E-selectin. We have also demonstrated that the adhesion of tumor cells to IL-1 beta-treated human umbilical vein endothelial cells can be inhibited by anti-NF kappa B reagents such as N-acetyl L-cysteine, aspirin, or pentoxifylline. These observations indicate the involvement of NF kappa B in cancer metastasis and the feasibility of using anti-NF kappa B reagents in preventing metastasis.

Rational Basis for the Use of Bergamot Essential Oil in Complementary Medicine to Treat Chronic Pain.

In complementary medicine, aromatherapy uses essential oils to improve agitation and aggression observed in dementia, mood, depression, anxiety and chronic pain. Preclinical research studies have reported that the essential oil obtained from bergamot (BEO) fruit (Citrus bergamia, Risso) modifies normal and pathological synaptic plasticity implicated, for instance, in nociceptive and neuropathic pain. Interestingly, recent results indicated that BEO modulates sensitive perception of pain in different models of nociceptive, inflammatory and neuropathic pain modulating endogenous systems. Thus, local administration of BEO inhibited the nociceptive behavioral effect induced by intraplantar injection of capsaicin or formalin in mice. Similar effects were observed with linalool and linalyl acetate, major volatile components of the phytocomplex, Pharmacological studies showed that the latter effects are reversed by local or systemic pretreatment with the opioid antagonist naloxone hydrochloride alike with naloxone methiodide, high affinity peripheral µ-opioid receptor antagonist. These results and the synergistic effect observed following systemic or intrathecal injection of an inactive dose of morphine with BEO or linalool indicated an activation of peripheral opioid system. Recently, in neuropathic pain models systemic or local administration of BEO or linalool induced antiallodynic effects. In particular, in partial sciatic nerve ligation (PSNL) model, intraplantar injection of the phytocomplex or linalool in the ipsilateral hindpaw, but not in the contralateral, reduced PSNL-induced extracellularsignal- regulated kinase (ERK) activation and mechanical allodynia. In neuropathic pain high doses of morphine are needed to reduce pain. Interestingly, combination of inactive doses of BEO or linalool with a low dose of morphine induced antiallodynic effects in mice. Peripheral cannabinoid and opioid systems appear to be involved in the antinociception produced by intraplantar injection of ß -caryophyllene, present in different essential oils including BEO. The data gathered so far indicate that the essential oil of bergamot is endowed with antinociceptive and antiallodynic effects and contribute to form the rational basis for rigorous testing of its efficacy in complementary medicine.

Role of intracellular SOD in protecting human leukemic and cancer cells against superoxide and radiation.

Many anticancer drugs have been shown to produce superoxide anion (O2.-) and seem to involve O2.- in their mode of action. Ionizing radiation provokes the decomposition reaction of water, producing a variety of reactive oxygen species, including O2.-. The finding that cancer cells are generally low in SOD activity may offer a theoretical base for radiation therapy and chemotherapy. The purpose of this study was to examine the protective effect of intracellular SOD against cytotoxicity induced by O2.- or radiation and to investigate whether exogenous SOD can protect cells from O2.-(-) and radiation-induced cytotoxicity. For this purpose, xanthine (X) and xanthine oxidase (XOD) were employed as an O2.- (-)generating system, and a linear accelerator was used for ionizing radiation. Cytotoxicity against monolayer cancer cell lines and leukemic cell lines was estimated by measuring the release of lactate dehydrogenase from these cells. The results revealed that the resistibilites to X- and XOD-generated O2.- and radiation correlated with intracellular Cu. Zn-SOD levels and that exogenous SOD could only slightly reduce X- and XOD-induced cytotoxicity while having no influence on radiation-induced cytotoxicity. Thus, intracellular SOD may play a central role in protecting cancer cells against reactive oxygen species generated by anticancer drugs and radiation.

Beta-interferon and early stage HIV infection.

beta-Interferon (IFN-beta) was evaluated prospectively for its antiviral activities in early stage human immunodeficiency virus (HIV) infection. Ten patients with hemophilia and HIV infection [8 asymptomatic carriers (AC) and 2 AIDS-related complex (ARC)] were intravenously injected with 1 million IU of IFN-beta twice a week for 6 months. For comparison, seven patients (six AC and one ARC) with hemophilia and HIV infection were observed for the same time period without any drugs. One episode of localized herpes zoster each occurred during the trial in the IFN group and in the control group. There were no significant differences in the absolute number of CD4+ lymphocytes and ratios of CD4+/CD8+ lymphocytes between the two groups. Recipients had flu-like symptoms but no serious toxicities. No clinical and immunological benefits to patients with early stage HIV infection were observed during the 6 months of treatment.

Behavioural and electrocortical changes induced by muscimol in rats withdrawn from chronic treatment with diazepam.

In rats withdrawn from a chronic treatment with diazepam, the effects of muscimol, given into the III cerebral ventricle, on behaviour and spectrum power of activity in the electrocorticogram (ECoG) were studied. In comparison to control rats which received only muscimol, in rats pretreated with diazepam (1 mg/kg/day for 30 consecutive days) the behavioural and ECoG effects of muscimol were significantly reduced or abolished. In fact, in rats pretreated with diazepam a small dose (50 ng) of muscimol did not affect behaviour or ECoG activity, in contrast to control animals in which the same dose produced, after a period of locomotor stimulation and ECoG desynchronization, typical and long-lasting behavioural sedation or sleep accompanied by a significant increase in total voltage power and in the lower frequency bands in the ECoG. In addition, larger doses (100 and 200 ng) of muscimol, which in control rats produced a typical biphasic pattern of ECoG and behavioural changes, i.e. an initial period of ECoG desynchronization and behavioural stimulation, followed by a second period of behavioural and ECoG sleep, in animals pretreated with diazepam, produced only an increase in total voltage power and in the lower frequency bands in the ECoG resembling the effects of the smaller (50 ng) dose. The present experiments suggest that, after chronic stimulation of benzodiazepine receptors a decrease in sensitivity of receptors for gamma-aminobutyric acid (GABA) occurs, since the effects of muscimol on behaviour and spectrum power were significantly reduced or abolished.

The capsaicin test in mice for evaluating tachykinin antagonists in the spinal cord.

A capsaicin test involving peripheral nociception, which produces behaviour similar to that elicited by formalin, is described in mice. Capsaicin was injected subcutaneously (s.c.) into the dorsal surface of a hindpaw and the time the animals spent licking the paw was recorded. Doses of capsaicin of 6.25-1600 ng induced nociception, during a period of 5 min, starting immediately after injection and disappearing completely at 10 min. Intrathecally (i.t.) administered [D-Arg1,D-Trp7,9,Leu11]substance P (spantide), a tachykinin antagonist and [D-Phe7,D-His9]substance P (6-11), a selective antagonist of substance P (SP), inhibited the capsaicin-induced behaviour, in a dose-dependent manner. This licking behaviour was also inhibited by intrathecal administration of SP antiserum but not by somatostatin (SOM) antiserum. Intrathecal pretreatment with capsaicin resulted in a marked reduction of the licking response, following subcutaneous injection of capsaicin into the paw. Capsaicin-induced licking was not affected by intrathecal administration of cyclo[7-aminoheptanoyl-Phe-D-Trp-Lys-(OBz)-Thr], a SOM antagonist and by intrathecal pretreatment with cysteamine, a SOM depletor. This nociceptive test may allow discrimination between SP- and SOM-mediated responses in the spinal cord of the mouse.

Characterization of the hyperalgesic effect induced by intrathecal injection of substance P.

Substance P (SP) was administered to awake rats by injection into the lumbar subarachnoid space via an indwelling cannula. Intrathecal (i.t.) injection of substance P produced a dose-related hyperalgesic response in the tail-pressure assay. This hyperalgesic effect peaked at 1 min and returned to control level within 15 min. Tachyphylaxis to the action of substance P was not observed by successive intrathecal injections. The hyperalgesic effect induced by substance P was increased by pretreatment with naloxone and blocked by a large dose of morphine. A synthetic analogue (D-Pro2, D-Trp7,9)-substance P, was not found to block the action of substance P on mechanical responses. These results suggest that substance P apparently produces a direct action on spinal substance P receptors and the antagonistic effect of morphine on the hyperalgesia induced by substance P may be mediated through a postsynaptic mechanism in the spinal cord.

Behavioural and ECoG spectrum power effects after intraventricular injection of drugs altering dopaminergic transmission in rats.

In rats with cannulae permanently implanted into the third cerebral ventricle, the effects of different pharmacological manipulations affecting dopaminergic mechanisms, were studied on behaviour and electrocorticographic (ECoG) activity, continuously quantified in its spectrum power. The intraventricular injection (0.1-1 nmol) of (-)3PPP[3-(3-hydroxyphenyl) N-n-propylpiperidine], a specific agonist at dopamine (DA) autoreceptors, produced dose-dependent behavioural sedation or sleep and an increase in ECoG spectrum power, with a predominant increase in the lower frequency bands. Short episodes of stereotyped movements, wet-dog syndrome, penile grooming and erection were also observed. Similar behavioural and ECoG effects were elicited by the intraventricular injection of R-(+)-8-chloro-2,3,4,5-tetrohydro-3-methyl-5-phenyl-1H-3-benzazepi ne-7-ol (SCH 23390), a selective antagonist at D1 postsynaptic receptors, although these were preceded by a short period of behavioural and sexual stimulation. In addition, the intraventricular administration of some neuroleptics, chloropromazine and haloperidol, produced behavioural and ECoG slow wave sleep. No significant changes were observed with a neuroleptic drug, 1-sulpiride, which is reputed to act selectively as an antagonist at dopamine D2 receptors. In conclusion, the present experiments add new evidence in favour of the idea that dopaminergic mechanisms are involved in mammalian species in the control of arousal and that both post-synaptic D1 and D2 receptors may take part in such a control.

Behavioural characterization of substance P-induced nociceptive response in mice.

Intrathecal injection of substance P produced a behavioural syndrome, consisting of reciproacal hindlimb scratching and biting or fore- and hind-licking. Pretreatment with either an analogue of substance P, (D-Pro2, D-Trp7,9)-substance P (DPDT-SP) or (D-Arg1, D-Pro2,4, D-Trp7,9, Leu11)-substance P, given intrathecally, reduced the response to substance P in a dose-dependent manner. The behaviour induced by substance P was also inhibited by intrathecal, intracerebroventricular (i.c.v.) or intraperitoneal (i.p.) injection of morphine. Intrathecal or subcutaneous injection of naloxone showed a biphasic effect on substance P response; the substance P-induced nociceptive response was increased by a small dose of naloxone, while it was inversely decreased by a large dose of naloxone. The results with analogues of substance P support the hypothesis that substance P, injected intrathecally, acts directly on substance P receptors in the spinal cord. The nociceptive response induced by substance P appears to be controlled by endogenous opioids in the spinal cord.

Tolerance and cross-tolerance to the antinociceptive effects of [D-Arg2]-dermorphin tetrapeptide analogue and morphine.

Rats were given repeated subcutaneous injections of [D-Arg2, Sar4]-dermorphin (1-4) [DAS-DER-(1-4)] and/or morphine over a period of 4 or 7 days. Antinociception was determined at 90 min for DAS-DER (1-4) and 30 min for morphine after each morning injection (9:00 a.m.), using the tail-flick and digit pinching tests in rats. Subcutaneous administration of DAS-DER (1-4) and morphine produced the development of antinociceptive tolerance, respectively. A marked tolerance to DAS-DER (1-4) and morphine was seen in rats made tolerant to morphine. However, administration of morphine produced no significant decrement in the antinociceptive activity in rats made tolerant to DAS-DER (1-4). These results suggest that the site of action of DAS-DER (1-4) may be more limited than that of morphine in the nociceptive pathways, for lack of its antinociceptive efficacy in morphine-tolerant rats.

Intrathecal substance P analogue causes motor dysfunction in the rat.

(D-Pro2, Trp7,9)-substance P injected into the subarachnoid space produced a severe faccid extension of hindlimb in a dose-related manner in the rat. This motor dysfunction was neither reversed by naloxone, an opioid receptor antagonist nor by intrathecal SP. SP levels in the lumbar cord were markedly depleted in rats with hindlimb paralysis, though there was not significant changes in rats without paraplegia. These results suggest that DPDT-SP produces motor dysfunction which dose not appear to be mediated by opioid and SP receptors.

Spinal antinociception: comparison of a dermorphin tetrapeptide analogue, [D-arginine2, sarcosine4]-dermorphin (1-4) and morphine in rats.

Intracerebroventricular injections of [D-arginine2, sarcosine4]-dermorphin (1-4) (DAS-DER 1-4) and morphine produced a dose-dependent inhibition of the tail-flick response to thermal stimulation. The ED50 value for each drug was 3.23 (1.35-7.73) nmol/rat and 32.0 (13.3-76.6) nmol/rat, respectively. When injected into the spinal subarachnoid space, the ED50 value was 0.035 (0.015-0.086) nmol/rat for the tetrapeptide and 11.9 (5.7-25.2) nmol/rat for morphine, respectively. Antinociception induced by DAS-DER 1-4 and morphine, through the intracerebroventricular and intrathecal routes, was clearly reduced by pretreatment with a small dose of naloxone. After spinal transection, the antinociceptive potency of systemically-administered morphine was significantly reduced while that of DAS-DER 1-4 was unaltered. The activity of DAS-DER 1-4 and morphine was also reversed by naloxone in spinal animals. It is concluded that DAS-DER 1-4, a dermorphin analogue, has a minor supraspinal action but acts mainly at the level of the spinal cord, in contrast to the action of morphine.

Comparison of the antinociceptive effects of intracerebroventricular injection of kyotorphin, cyclo (N-methyl-Tyr-Arg) and Met-enkephalin in mice.

Intracerebroventricular (i.c.v.) administration of kyotorphin (L-Tyrosine-L-Arginine) or Metenkephalin (Met-ENK) to conscious mice resulted in a dose-dependent antinociceptive effect as measured by three pain tests. Cyclo(N-methyl-L-Tyrosine-L-Arginine) (cyclo NMTA), an analogue of kyotorphin, increased the reaction time in the tail-pressure and tail-flick tests. Both dipeptides also decreased writhing induced by acetic acid. However, the antinociceptive activity of cyclo NMTA was substantially greater than that of kyotorphin or Met-enkephalin. At the maximum effective dose of 62.7 nmol/mouse, this cyclic dipeptide produced a more long-lasting antinociceptive effect than did kyotorphin or Met-enkephalin. Antinociception induced by cyclo NMTA or kyotorphin was significantly reversed by pretreatment with naloxone (2 or 8 mg/kg, i.p.), though naloxone was not as effective an antagonist of the antinociceptive action of these peptides as it was against Met-enkephalin. The results indicate that the antinociceptive effect induced by cyclo NMTA may in part involve the endogenous opioid system in mice.

The effects of substance P analogues on the scratching, biting and licking response induced by intrathecal injection of N-methyl-D-aspartate in mice.

1. Intrathecal (i.t.) administration of N-methyl-D-aspartate (NMDA) elicited a dose-dependent behavioural response consisting of licking, biting and scratching in mice. 2. Repeated i.t. injections of 0.4 nmol NMDA, at 5 min intervals, resulted in the rapid development of desensitization to this NMDA-induced behavioural phenomenon. 3. The NMDA-induced response was dose-dependently inhibited by the simultaneous injection of a selective NMDA-receptor antagonist, D-2-amino-5-phosphonovaleric acid. 4. The substance P (SP) analogues [D-Pro2, D-Trp7,9] SP and [D-Arg1, D-Trp7,9, Leu11] SP (spantide) inhibited NMDA-induced behavioural responses in a dose-dependent manner. However, [D-Phe7, D-His9] SP (6-11), a SP analogue selective for neurokinin1 (NK1) receptors, failed to inhibit NMDA-induced responses even at a dose of 4.0 nmol. 5. These results indicate that NMDA-induced behavioural responses are mainly mediated through NMDA receptors without affecting NK1 receptors in the spinal cord.