Primary diaphragmatic schwannoma with a typical target appearance: correlation of CT and MR imagings and histologic findings

A rare case of benign diaphragmatic schwannoma in a 38-year-old female is reported. Precontrast computed tomography (CT) showed an encapsulated well-defined round homogeneous tumor with central calcification, measuring approximately 5 cm in diameter, arising from the left diaphragm. Contrast-enhanced CT and gadolinium-enhanced T1-weighted magnetic resonance (MR) imaging showed focal enhancement in the central portion of the tumor. The tumor showed a typical target appearance of increased peripheral signal intensity and decreased central signal intensity on unenhanced T2-weighted images. Pathological examination of resected specimens of the tumor showed two zonal histological components: a hypercellular portion of spindle cells with nuclear palisading (Antoni A tissue) and a hypocellular portion of cells with cystic degeneration, together with focal calcification and hemangeomatous vascular changes (Antoni B tissue). We consider the radiological characteristics of diaphragmatic schwannoma on CT and MR imagings to represent the geographic difference between the histologic zones of the tumor.

Inhibitory effect of ascorbate on cell growth: relation to catalase activity

The effect of ascorbate on cell growth was examined using primary cultured hepatocytes and chondrocytes elicited from guinea pigs and six kinds of cell lines derived from the tissue and blood of mammals. Cells were cultured in medium supplemented with or without ascorbate at various concentrations for 24 and 48 h. There were differences among the cells used here in the effect of ascorbate on growth, and also in the concentrations of ascorbate required to lower cell viabilities. This indicates that different cell species have varying sensitivities to ascorbate in medium. On the other hand, cells such as HL-60, which showed growth inhibition at higher concentrations of ascorbate in medium among observed cells, were damaged by the exposure to higher concentrations of hydrogen peroxide (H2O2). Furthermore, there was a positive correlation between the activity of catalase in cells that decomposed H2O2 and the concentration of ascorbate required to lower cell viability (p < 0.01). These results indicate that the concentration of ascorbate in medium required to inhibit cell growth depends on the activity of catalase in the cells.

Differences in the reduced 18F-Dopa uptakes of the caudate and the putamen in Parkinson's disease: correlations with the three main symptoms

It has been reported that the F-Dopa (FD) uptake in patients with idiopathic Parkinson's disease (PD) decreased significantly in the caudate and putamen when compared to controls. The FD uptake severely decreased in the putamen, while it was relatively spared in the caudate nucleus. We also previously reported that atypical parkinsonism with no or little tremor showed a homogeneously reduced FD uptake in both the caudate and the putamen. In this study we evaluated the caudate and the putaminal FD uptakes in relation to the three main symptoms in PD. The FD uptake was measured by PET with 6-L-[18F]fluorodopa in 17 patients with PD. The caudate and the putaminal FD uptake ratios to the cerebellum at 120 min were evaluated. The caudate and the putaminal FD uptake ratios in the patients with PD decreased as their clinical stages advanced. These decreases also correlated with the degree of rigidity and bradykinesia. However, such decreases did not correlate with the degree of tremor. The caudate-putamen index (CPI)(%), which was calculated by a formula based on the difference in the uptakes of the caudate and putamen divided by the caudate uptake, indicated 11.6 +/- 3.6, 16.5 +/- 5.5 and 18.3 +/- 4.1 in the group of no, mild and moderate tremor, respectively, and increased as the degree of tremor advanced. The CPI in the group of moderate tremor significantly increased from that in the group of no tremor (P < 0.04). However, the CPI did not correlate with the clinical stage, the degree of rigidity or the degree of bradykinesia. The FD/PET study therefore effectively demonstrated the severity of the clinical symptoms of rigidity and bradykinesia in patients with PD in correlation with a decrease in the FD uptakes in the caudate and the putamen, and it also demonstrated that the severity of tremor might have a different mechanism from that of such other symptoms as rigidity and bradykinesia.

[Hypoplastic mixed lineage leukemia successfully treated with low-dose cytosine arabinoside]

A 54-year-old male was admitted because of dyspnea on exercise. His peripheral blood revealed pancytopenia with severely hypoplastic bone marrow. Bone marrow aspiration showed a marked hypocellular marrow with 62.4% of blast cells. Cytochemical studies showed that peroxidase activity, alpha-nephtyl buthylate esterase activity and PAS reaction were negative, and that only ASD-chroloacetate esterase activity was positive. Surface marker analysis of blast cells showed positive result for CD5, 7, 33 and 34 antigens. The T-cell receptor beta gene was rearranged, but the immunoglobulin H chain gene showed a germ line configuration. Terminal Deoxynucleotydyl Transferase (TdT) was positive, but cellular surface and cytoplasmic immunoglobulin were not recognized. A diagnosis of hypoplastic mixed lineage leukemia was made and treated with low dose cytosine arabinoside, he resulted in complete remission. The relation between hypoplastic leukemia, AML-M0 and mixed lineage leukemia was also discussed.

[The relief of postoperative pain by suppositories of buprenorphine or NSAID]

We evaluated the effects of suppositories of buprenorphine (BN) or NSAID (supp.) preoperatively administered for postoperative pain relief in patients who underwent elective gynecological surgeries. Fifty six patients were randomized into four groups: group B; 0.4 mg BN supp., group B+I; 0.4 mg BN supp. and 50 mg indomethacine (IND) supp., group B+D; 0.4 mg BN supp. and 50 mg diclofenac supp., group C; no supp. given as control. They were administered rectally after induction of general anesthesia. In all the supp. groups the patients had good pain relief during the first 24 hrs after the administration of supp. Group B+I seemed to have better pain relief, but, there was no statistical significance among the 3 groups. Nausea and vomiting were observed more frequently in group B and in control group C than in NSAIDs combined groups. The difference in the incidence rates was not significant. In conclusion, the simultaneous administration of BN and IND supp. was considered to be useful for postoperative pain relief without producing major side effects.

A case of alpha-fetoprotein-producing gastric cancer showing an exogastric growth pattern

A case of alpha-fetoprotein (AFP)-producing gastric cancer, which showed a huge abdominal mass due to an exogastric growth, is here described. A 69-year-old Japanese woman with a huge abdominal mass, measuring 22 x 15 cm in size, had a serum AFP level that was exceptionally high (155 x 10(3) ng/ml). CT, barium meal studies, and gastrointestinal fiberoscopy revealed a gastric tumor with an exogastric growth pattern. The patient underwent a partial gastrectomy. The histological examination revealed that the tumor consisted of anaplastic carcinoma with positive staining for AFP. Although no liver metastasis was observed at operation, she died of multiple liver metastases 8 weeks after the operation. A gastric cancer that shows both AFP production and an exogastric growth pattern is quite rare and may be virulent.

[Influences of a shiitake (Lentinus edodes)-fructo-oligosaccharide mixture (SK-204) on experimental pulmonary thrombosis in rats]

Effects of the mixture (SK-204) consisting of dried shiitake mushroom (Lentinus edodes) treated with wet-heating and fructo-oligosaccharides (7:3) on the experimental models of pulmonary thrombosis induced by lactic acidosis in rats were evaluated. Chronic oral administration (10 weeks) of SK-204 significantly prevented the thrombus formation on this thrombosis model. However, decreases in the numbers of platelet and fibrinogen level by lactate were not changed by SK-204. These results suggest that SK-204 have an anti-thrombotic action, which is due to neither the inhibition of platelet aggregation nor coagulation, but probably due to the promotion of fibrinolysis and thrombolysis.

A detoxication route for acetaldehyde: metabolism of diacetyl, acetoin, and 2,3-butanediol in liver homogenate and perfused liver of rats

The metabolism of diacetyl (2,3-butanedione), acetoin (3-hydroxy-2-butanone), and 2,3-butanediol, which are metabolites of acetaldehyde was quantitatively investigated using rat liver homogenate, liver perfusion, and in vivo experiments. Diacetyl and acetoin were reduced to 2,3-butanediol in these experiments, but acetoin and 2,3-butanediol were scarcely oxidized to diacetyl, indicating that the reduction reaction to 2,3-butanediol from diacetyl occurs actively in rat liver. The formation of acetoin from diacetyl required either NADH or NADPH as a reductant, while the reduction of acetoin to 2,3-butanediol required NADH. Acetoin and 2,3-butanediol were more readily accumulated than diacetyl in brain tissue.

Metal-chelating inhibitors of a zinc finger protein HIV-EP1. Remarkable potentiation of inhibitory activity by introduction of SH groups

HIV-EP1 is a C2H2 type zinc finger protein which binds to DNA kappa B site present in the long terminal repeat of HIV provirus. Previously we have reported zinc chelators having histidine--pyridine--histidine skeleton and were successful in inhibiting the DNA binding of HIV-EP1 by removing zinc from the zinc finger domain. Aiming at the potentiation of the inhibitory activity of our previous zinc chelators, herein synthesized were novel chelators comprising pyridine and aminoalkanethiol. These showed marked inhibitory activity on the DNA binding of HIV-EP1. In particular, one of them having a bis(2-mercaptoethyl) amino side chain showed inhibitory activity (IC50, approximately 4 microM) 10 times stronger than that of the strongest inhibitor that we reported previously. It appeared that these inhibited the DNA binding of HIV-EP1 by a mechanism distinct from that of the previous histidine-based inhibitors.

Comparative evaluation of mean particle size of bulk drug powder in pharmaceutical preparations by Fourier-transformed powder diffuse reflectance infrared spectroscopy and dissolution kinetics

This paper reports a quantitative correlation between specific FT-IR absorption peak intensity of phenytoin (PTH) to its particle size in the bulk as well as in powder blends. Absorption peak intensity in FT-IR spectra of phenytoin (PHT) increased with decrease of mean particle size of the powders. The relationships between the FT-IR absorbance at 1724 cm-1 of PHT and the specific surface area (Sw) obtained by the BET N2 gas absorption method or the reciprocal of mean particle size (D50) obtained by particle counting of SEM photomicrographs of ground samples showed straight lines, indicating that the absorbance followed the equation log (lo/l) = K1/D50 = K2Sw, where lo and l are intensities of the incident and transmitted light, respectively, and K1 and K2 are constants. In binary mixture of powders containing 50% PHT and 50% lactose, the relationship between the absorbance at 1724 cm-1 of PHT powder and Sw of the reciprocal of D50 also gave a linear plot. The dissolution behaviors of the binary mixture samples were measured in pH 1.2 buffer containing 0.1% sodium lauryl sulfate at 37 degrees C. The data from initial rates of dissolution of the binary mixture was utilized to calculate the particle size (Dg) using the Hixon-Crowell equation, and these particle size values were consistent with those obtained from Sw data as well as the absorbance data by the IR spectral method.

A self-setting TTCP-DCPD apatite cement for release of vancomycin

Vancomycin (VCM), a methiciline-cefem resistant Staphylococcus aureus (MRSA)-specific antibiotic, was incorporated in a self-setting tetracalcium phosphate (TTCP)-dicalcium phosphate dihydrate (DCPD) apatite cement that hardened isothermally into a hydroxyapatite (HAP) phase with crystallinity similar to that of host bone. Effective release of VCM into PBS lasted for 2 weeks from cements containing 1% VCM and for longer than 9 weeks from cements containing 5% VCM. The rate of release of VCM differed between cements with different crystallinities as well as between the two dissolution media, PBS and simulated body fluid. Mean concentration of VCM in the bone marrow tissue released from cements containing 5% VCM was 20 times the minimum inhibitory concentration 3 weeks after implantation in bone. Direct contact with new bone was observed with the cements containing 1% VCM. Slow delivery of VCM from a self-setting TTCP-DCPD apatite cement with low crystallinity could be used to treat MRSA osteomyelitis.

Determination of acetylcholine concentration in cerebrospinal fluid of patients with neurologic diseases

INTRODUCTION

Acetylcholine (ACh) is a well known neurotransmitter in the central nervous system, but determining its level in cerebrospinal fluid (CSF) is very difficult and the origin of CSF ACh is still unknown. In this study, we attempted to measure CSF ACh by a specific and sensitive radioimmunoassay (RIA) from patients with neurologic diseases.

MATERIAL AND METHODS

Patients with cerebral infarction (n = 7), Parkinson's disease (n = 6), spinocerebellar degeneration (n = 6), Alzheimer's disease (n = 3), amyotrophic lateral sclerosis (n = 3) and disc herniation with no central nervous involvement (n = 8) participated to determine the CSF ACh levels.

RESULTS

Of these 33 patients, the mean ACh level in CSF was 282.2 +/- 61.7 fmol/ml (mean +/- SE, range 20-1505.8 fmol/ml). The mean ACh level of spinocerebellar degeneration group was lower than others, but not statistically significant.

CONCLUSION

We conclude that an amount of ACh detectable by RIA is certainly present in CSF.

Calculation of intercrystalline solution composition during in vitro subsurface lesion formation in dental minerals

Applications of a novel technique to calculate intercrystalline solution composition during enamel demineralization are presented. Bovine tooth enamel blocks and carbonated apatite (CAP) compressed disks were demineralized in an in vitro subsurface lesion system. The demineralization medium was a 0.1 M acetate buffer at pH 4.5, containing calcium, phosphate, and fluoride (0.5 ppm). Mineral samples were demineralized for various times, and fluoride profiles and mineral density profiles of these samples were determined by electron microprobe and X-ray microradiography, respectively. A model independent data analysis (MIDA) technique uses these data along with the differential equations for mass transfer and permits calculation of the local intercrystalline solution composition profiles inside the porous mineral matrix as functions of time and position. The invariance in diffusivity with time as calculated in the analysis was taken as an indicator of the physical reasonableness of the method. Current outcomes suggest that it is the sharp gradient of fluoride concentration in the intercrystalline solution which causes the formation of subsurface lesions. Since the driving force for mineral dissolution is a function of solution composition, a gradient of this driving force is consequently formed. Using a compressed disk of carbonated apatite powder as a model for block enamel excluded the possibility of the existence of a gradient of mineral composition which could also cause a gradient of the driving force for mineral dissolution. An FAP surface complex hypothesis is consistent with the current view that fluoride in the intercrystalline solution has a stronger inhibition effect on the dissolution of mineral than does fluoride in the mineral phase. With the help of the MIDA technique, calculated results indicate that the mechanism of the formation of subsurface lesions is dynamically controlled by the intercrystalline solution composition.

Effect of cogrinding with various kinds of surfactants on the dissolution behavior of phenytoin

The physicochemical properties of phenytoin (PHT) combined with various kinds of surfactants at 40 w/w % such as sodium lauryl sulfate (SLS), sodium deoxycholate (DCNa), and the sucrose ester of stearic acid (SE) by a cogrinding method were investigated by X-ray diffraction analysis, Fourier transformed infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and dissolution kinetics in 2nd fluid (Japanese Pharmacopoeia XII, pH 6.8, 37 degrees C). All X-ray diffraction peak intensities of the coground mixtures were decreased by grinding, and the product with DCNa grinding for 3 h transformed into a noncrystalline solid, but the products with SE and SLS were not. The solubilities of ground products with SLS and SE were almost the same as those of respective physical mixtures. However, the apparent solubility of ground products with DCNa was 28.7 times higher than that of the physical mixture.

Synthesis and protein tyrosine phosphatase inhibitory activity of dephostatin analogs

We have synthesized derivatives of dephostatin, a protein tyrosine phosphatase (PTPase) inhibitor, to study the structure-activity relationships of this inhibitor. Inactive analogs revealed some insight into structural requirements or PTPase inhibitory activity of dephostatin. Both a nitroso group and phenolic hydroxyl groups were found to be essential for the inhibitory activity. Among the dephostatin derivative synthesized, one of the regioisomers of dephostatin showed PTPase inhibitory activity equivalent to that of dephostatin, and also had increased stability.

Nigrofrontal dopaminergic function as assessed by 18F-dopa PET

The existence of the nigrofrontal dopaminergic pathway has been demonstrated in neuroanatomical studies. We evaluated the presynaptic nigrofrontal dopaminergic function using 18F-dopa (FD) positron emission tomography (PET). The multiple time PET data in the frontal cortex from 20 to 70 min post-injection for FD were evaluated by Patlak analysis using the cerebellar time-activity curve as an input function. The frontal FD uptake rate constants could not be determined in 5 of 12 normal volunteers because of large deviations in the plots. There were no significant differences between the subjects among whom the frontal FD uptake rate constants could or could not be determined regarding the amount of FD injected, the frontal 18F counts, or whether or not they were pretreated with carbidopa. The uptake constants were determined in 9 or 12 patients with parkinsonian syndrome. While the mean (+/- S.D.) uptake constants in patients with Parkinson's disease (2.89 +/- 0.06 x 10(-3), n = 4) and in patients with progressive supranuclear palsy (2.81 +/- 0.10 x 10(-3), n = 3) were not significantly different from those in the normal volunteers (2.93 +/- 0.14 x 10(-3)), those in two patients with corticobasal degeneration (2.42 and 2.46, respectively) decreased in comparison to the control values. Differences in the nigrofrontal presynaptic dopaminergic function as assessed by FD-PET may explain the different pathogenesis and also help to differentiate between corticobasal degeneration and other parkinsonian syndromes, such as Parkinson's disease and progressive supranuclear palsy.

Cupric ion blocks NF kappa B activation through inhibiting the signal-induced phosphorylation of I kappa B alpha

A transcription factor NF kappa B, which regulates expression of various cellular genes involved in immune responses and viral genes including HIV, is sequestered in the cytoplasm as a complex with an inhibitory protein I kappa B. Various extracellular signals induce phosphorylation and rapid degradation of I kappa B alpha to release NF kappa B. Cu2+ was found to inhibit the activation of NF kappa B induced by TNF-alpha, TPA, or H2O2. Deoxycholate treatment of the cytoplasmic extract prepared from cells stimulated by TNF-alpha in the presence of Cu2+ resulted in the release of NF kappa B from I kappa B alpha, indicating that Cu2+ interferes with the dissociation of the NF kappa B-I kappa B complex. Neither phosphorylation nor degradation of I kappa B alpha was observed upon TNF-alpha stimulation in the presence of Cu2+. These results indicate that Cu2+ inhibits the release of NF kappa B by blockade of a signal leading to the phosphorylation of I kappa B alpha.

Characteristics of substance P-evoked release of amino acids from neonatal rat spinal cord

The characteristics of release of amino acids evoked by substance P from the neonatal rat spinal cord were examined. A hemisected spinal cord was continuously perfused and the release of amino acids into the perfusate was measured using high-performance liquid chromatography with a precolumn derivatization technique. Substance P (10 microM) evoked a significant increase in the release of aspartate, glutamate, GABA, glycine and taurine. The substance P-evoked release of these five amino acids was not reduced by Ca(2+)-free medium, but was blocked by [D-Pro4,D-Trp] substance P4-11 (10 microM). Perfusion of the spinal cord with low-Na+ medium (22 mM) induced a marked increase in the high-K+ (90mM)-evoked release of GABA, glutamate and glycine. In contrast, the substance P-evoked release of the five amino acids was significantly decreased by the low-Na+ medium. Similarly, perfusion of the spinal cord with low-Cl- medium (8 mM) increased the high-K(+)-evoked release of GABA and glycine, but decreased the substance P-evoked release of GABA, glycine and taurine. The substance P-evoked release of the five amino acids was dose-dependently blocked by d-tubocurarine (3-10 microM), whereas it was not blocked by tetrodotoxin (0.2 microM) or amiloride (30 microM). Compound 48/80 (10 micrograms/ml), a histamine-releasing agent on mast cells, evoked release of the amino acids from the spinal cord with characteristics similar to those of substance P-evoked amino acid release.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of the intestinal T-lymphocyte-associated-molecule recognized by the HML-1 antibody on mononuclear cells from HTLV-I-infected subjects

We investigated the expression of a monoclonal antibody (HML-1) defined antigen that appears on human intestinal T-lymphocytes in HTLV-I-related disease. We studied 25 ATL, and 24 healthy HTLV-I carriers. Patients with acute ATL showed a variety of the expression of the HML-1 antigen (range 0.4-74.8%). HML-1 expression on mononuclear cells (MNCs) in blood from patients with chronic ATL ranged from 1.7-43.6% (mean 13.5%). This level of expression was less than that of patients with acute ATL, but not significantly. In patients with smoldering ATL, the degree of patients with acute ATL, but not significantly. In patients with smoldering ATL, the degree of expression ranged from 1.6-13.3% (mean 8.0%). In contrast to patients with acute ATL, MNCs from patients with acute myelogenous leukemia (AML), acute lymphocytic leukemia (ALL), and B-cell type chronic lymphocytic leukemia (B-CLL) did not express the HML-1 antigen, except for the 2 patients with ALL. Healthy HTLV-I carriers and healthy controls also were negative for HML-1 reactivity. In acute ATL, patients with gastrointestinal tract infiltration tended to have high expression of the HML-1 epitope. After stimulation with phytohemagglutinin (PHA), healthy HTLV-I carriers showed significantly increased expression of the HML-1 epitope (P < 0.05). Recently, the beta 7 integrin family has been found to play a specific role in mucosal localization or adhesion, and HML-1 protein was found to match the deduced beta 7 N-terminal sequence. We propose that the cellular gene responsible for HML-1 epitope expression may, like IL-2, IL-2R, etc., be transactivated by infection with HTLV-I, and HML-1 antigen gene expression by HTLV-I infection may lead to infiltration of ATL cells with highly expressed HML-1 epitope into the gut mucosa.

[Intra-arterial 5-FU/intra-venous MTX therapy for metastatic liver lesions]

We have performed intra-arterial 5-fluorouracil (5-FU)/intra-venous methotrexate (MTX) therapy for 4 patients with multiple metastatic liver tumors at out-patient clinic. Primary lesions were of the stomach (one patient, synchronous) and colon (3 patients, two were synchronous and one was metachronous). 5-FU (250-350 mg/day) was continuously infused for two weeks into the hepatic artery through the reservoir using the Baxter Infuser (multi-day type). MTX (100 mg/m2) was infused into the peripheral vein on days 1, 8 and 15. Leucovorin calcium (15 mg) was orally administered three times after MTX infusion. All patients partially responded, and no remarkable side effect was detected. We propose that this new combination therapy, that is intra-arterial 5-FU and intra-venous MTX for metastatic liver cancer, can be useful and safe even for out-patients.

Novel zinc chelators with dual activity in the inhibition of the kappa B site-binding proteins HIV-EP1 and NF-kappa B

Both HIV-EP1 (also called PRDII-BF1 or MBP-1), a zinc finger protein, and NF-kappa B, a Rel family protein, bind to kappa B site present in the enhancer of multiple cellular and viral genes involved in immune function and inflammatory response including HIV-1 LTR and human interferon beta gene. When cells are exposed to extracellular stimuli such as virus or phorbol ester, the activity of both HIV-EP1 and NF-kappa B is induced. Thus, kappa B site-directed transcription could be regulated by two distinct proteins in a cooperative way. Novel heterocyclic compounds comprising (dimethylamino)pyridine and histidine units, i.e., 1-4, have been designed and synthesized, aiming at inhibition of these kappa B site-binding proteins to discriminate their functions. These compounds exhibited remarkable zinc-binding capability as revealed by NMR study. Compounds 1 and 2 showed a marked inhibitory effect on the DNA binding activity of HIV-EP1 by removing zinc without interfering with the DNA binding activity of NF-kappa B. Since it has been demonstrated that zinc somehow influences the DNA binding of NF-kappa B, the effect of these heterocyclic compounds and their zinc complexes on NF-kappa B was examined. Zinc complexes of 3 and 4 exhibited the inhibitory effect on the DNA binding of NF-kappa B and/or homodimeric complexes of p50 and p65 subunits of NF-kappa B without affecting HIV-EP1. Thus, it became possible to inhibit either one of the two kappa B site-binding proteins without inhibiting the other.(ABSTRACT TRUNCATED AT 250 WORDS)

[Double cancer in patients with adult T cell leukemia]

We have studied the incidence and characteristics of associated neoplasms in 210 ATL patients. Twelve patients had other primary neoplasms and the incidence of double cancer was 5.7%. The additional malignancies in ATL patients consisted of 4 cases of stomach, 3 cases of colon and one of each lung, ovary, uterus, liver and bladder cancer. In metachronous double cancer patients, the neoplasm was found before the time of diagnosis of ATL in 5 out of 6 patients. Immunodeficiency due to HTLV-I infection as well as chemotherapy for the preceding neoplasm are suggested to be related to the leukemogenesis of ATL.

Pharmacological characterization of GR82334, a tachykinin NK1 receptor antagonist, in the isolated spinal cord of the neonatal rat

Pharmacological characteristics of [D-Pro9,[spiro-gamma-lactam]Leu10,Trp11]physalaemin-(1-11) (GR82334), a tachykinin NK1 receptor antagonist, and its effects on slow depolarizing responses of lumbar ventral roots evoked by primary afferent stimulation were examined in isolated spinal cord preparations of neonatal rats. GR82334 (1-3 microM) caused dose-dependent rightward shifts of the concentration-response curves for substance P, substance P methyl ester, delta-aminovaleryl [Pro9,N-Me-Leu10]substance P-(7-11) (GR73632) and neurokinin A in normal artificial cerebrospinal fluid and those for substance P methyl ester, GR73632 and neurokinin A in the presence of tetrodotoxin. GR82334 (10 microM) did not evoke gamma-aminobutyric acid (GABA) release from spinal cords of neonatal rats, whereas [D-Pro9,[spiro-gamma-lactam] Leu10,Trp11]substance P (GR71251), another tachykinin NK1 receptor antagonist, induced a significant increase in GABA release. GR82334 (1-3 microM) markedly depressed the slow depolarizing response of ventral roots, referred to as slow ventral root potential, evoked by the stimulation of the contralateral dorsal root or the ipsilateral saphenous nerve. In contrast, cyclo[Gln,Trp,Phe,Gly,Leu,Met] (L-659,877, 1 microM), a selective tachykinin NK2 receptor antagonist, did not depress the saphenous nerve-evoked slow ventral root potential and did not antagonize the action of neurokinin A to induce ventral root depolarization. The present results provide further evidence for the involvement of substance P, neurokinin A and tachykinin NK1 receptors in the primary afferent-evoked slow ventral root potentials.