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Objective Lupus nephritis, which shows various histologic patterns, is a serious complication of systemic lupus erythematosus (SLE). We previously demonstrated the importance of Th1 cell–mediated immune response in patients with diffuse proliferative lupus nephritis (DPLN). The aim of this study was to examine the relationship between the peripheral blood Th1/Th2 balance and the intrarenal immune response. Methods The Th1:Th2 ratio in peripheral blood was measured by intracellular staining for cytokines with flow cytometry. Immunohistochemical analysis of renal biopsy specimens was performed to clarify the characterization of local infiltrating cells in 3 groups of subjects: SLE patients with World Health Organization (WHO) class IV nephritis (DPLN) (group I; n = 13), SLE patients with WHO class V nephritis (group II; n = 9), and patients with minor glomerular lesions (group III; n = 7). In addition, the histologic activity index and chronicity index were evaluated and correlated with the Th1:Th2 ratio. Results Immunohistochemical studies showed higher numbers of CD68+ macrophages, CD3+ T cells, and interferon-γ–positive cells in group I than in groups II or III. Renal tissues from patients in group I also showed up-regulation of expression of osteopontin and CD40, with a small number of infiltrating T cells expressing interleukin-4. Overall, the Th1:Th2 ratio in group I patients (SLE with DPLN) was high and correlated significantly with the histologic activity index, but not with the chronicity index. Conclusion We have identified a predominance of Th1-type response in both peripheral and renal tissues of patients with DPLN, suggesting that the peripheral blood Th1:Th2 ratio directly reflects the local histopathologic findings. In patients with lupus nephritis, the peripheral blood Th1:Th2 ratio could be useful as a parameter that reflects the renal histologic activity or the strength of the local Th1 response.

Objective. Systemic lupus erythematosus (SLE) in a multisystem autoimmune disorder characterized by multiorgan pathology and autoantibodies against a variety of autoantigens. The CD28 and CTLA-4 genes might be candidate genes for SLE, because costimulation signals from CD80 CD86 to CD28 CTLA-4 have been suggested to play an important role in the activation or inactivation of T lymphocytes. Methods. We investigated three polymorphic regions within the CTLA-4 gene, a C/T base exchange in the promoter region -318 (CTLA-4 -318C/T), an A/G substitution in the exon 1 position 49 (CTLA-4 49A/G). an (AT) n repeat polymorphism in the 3' untranslated region of exon 4 [CTLA-4 3' (AT) n ], and a CD28 gene polymorphism, a T/C substitution in the intron 3 position + 17 (CD28 IVS3 + 17T/C), in SLE patients and controls. Results. SLE patients had significantly higher frequencies of the CTLA-4 49G allele (P = 0.003) and of the CTLA-4 (AT) n 106 bp allele (P = 0.0008) than controls. We also found a strong linkage disequilibrium between the A allele of CTLA-4 49A/G and the 86 bp allele of CTLA-4 3' (AT) n . On the contrary, no association was found between SLE and CTLA-4 -318C/T or CD28 IVS3 + 17T/C. Conclusion. We conclude that the CTLA-4 gene appears to play a significant role in the development of SLE in the Japanese population.

A 72-year-old woman with 5-year history of essential hypertension developed peritoneal tuberculosis. The patient's hypertension, which had been well-controlled by long-acting nifedipine, deteriorated after the administration of rifampicin, an antitubercular agent. During use of nifedipine and rifampicin, both the peak plasma concentration and the area under the curve of nifedipine decreased markedly to about 40% of those without rifampicin. The findings suggest that rifampicin may increase the elimination of nifedipine, presumably by induction of its hepatic metabolism. Nisoldipine, another calcium antagonist, also failed to lower the patient's blood pressure, when given in combination with rifampicin. Taken together, these findings indicate that more caution should be urged when calcium antagonist is prescribed along with rifampicin.

Objective: To study the effect of interleukin (IL)-4 and IL-10 on nitric oxide (NO) production by macrophages.¶Materials and Methods: Elicited or resident peritoneal macrophages (PMO) and a macrophage cell line Raw264.7 were primed by IL-4 or IL-10 for 6 hours, and were further incubated in the presence of interferon (IFN)-γ and/or lipopolysaccharide (LPS) for 48 hours. NO2 - accumulation in the supernatant of cultured cells was used as an indicator of NO production and was determined by the standard Griess reaction adapted for microplates. The amount of tumor necrosis factor (TNF)-α in the culture supernatants was determined with a commercially available ELISA kit. The absorbance was measured at 450 nm with a microplate photometer.¶Results: IL-4 inhibited NO production by murine macrophages of different sources and the macrophage cell line Raw264.7. In contrast, different macrophage populations showed differential responses to IL-10. After stimulation with LPS or IFN-γ, IL-10 suppressed NO production by elicited PMO but enhanced NO production by resident PMO or by Raw264.7. Both IL-4 and IL-10 inhibited the production of TNF-α, which has been shown to play a crucial role in NO production. In the presence or the absence of blocking antibody to TNF-α, IL-10 always enhanced NO production by resident PMO. This result suggests that the inhibition of TNF-α production and the enhancement of NO production by resident PMO stimulated with IL-10 are independent, coexisting events.¶Conclusions: Factors other than TNF-α have been suspected to influence NO production by macrophages, and this study indicates that IL-10 may be a candidate cytokine for resident PMO.

Objective To analyze the Th1/Th2 balance of peripheral Th cells in patients with systemic lupus erythematosus (SLE). Methods The Th1:Th2 ratio was analyzed in 3 groups: SLE without proteinuria (group I; n = 23), SLE with proteinuria (group II; n = 31), and normal controls (group III; n = 24). Group II patients who had undergone renal biopsy were classified into 3 subgroups based on their renal histopathologic findings. The intracellular cytokine detection method with flow cytometry was used to quantitate Th1 and Th2 cells. Results There was no difference in the mean Th1:Th2 ratio between SLE patients (groups I and II) and healthy controls (group III). However, the mean value in group II was significantly higher than those in groups I and III. Moreover, within group II, the mean value in SLE patients who had diffuse proliferative lupus nephritis (World Health Organization class IV) was especially high. Conclusion Although SLE has been considered to be a disease in which Th2 cells predominate, the Th1/Th2 balance of peripheral Th cells in SLE patients in the present study did not show a predominance of these cells. In contrast, among SLE patients with WHO class IV lupus nephritis, there was a strong predominance of Th1.

It has been demonstrated that interferon-gamma (IFN-gamma) and interleukin-10 (IL-10) have various reverse effects on macrophages; however, the molecular mechanism of this difference has not been fully understood. In this study, we analyzed the binding activity of IL-10- and IFN-gamma-activated STAT molecules to two kinds of GAS-motif sequences. IL-10-activated STAT1 could bind to the GAS-motif sequence in the promoter region of the Fcgamma receptor, but not to that in the promoter region of the COX-2 gene, whereas IFN-gamma-activated STAT1 and STAT5 could bind to both sequences. IL-10 inhibited IFN-gamma-induced STAT activation without newly synthesized protein. We further demonstrated that aspirin, but not dexamethasone, suppressed IFN-gamma-induced STAT activation. Taken together, these results suggest that IL-10-activated STAT1 has a specificity in binding to the GAS-motif sequences, whereas IFN-gamma-activated STAT1 and STAT5 have a broader spectrum in binding to the GAS-motif sequences. This may explain the difference between IL-10 and IFN-gamma in biological activity, and the inhibitory effect of IL-10 on IFN-gamma activities.

In this report, we presented the results that EGCG, the main constituent of the polyphenols present in Japanese green tea inhibited growth of leukemic cell lines of both human and mice. The proliferation of human leukemic cell lines and mouse NFS60 cell line was inhibited by EGCG. Sensitivity of each line to EGCG was different, and more than 50% of DNA synthesis was reduced in all the cell lines in the presence of 50 microM EGCG. On the other hand, normal hematopoietic progenitor cells retained their natural function of supplying mature cells of various lineages in the presence of less than 10 microM EGCG in vitro. Even in the presence of 100 microM EGCG, half the colonies containing all the lineages of cells were developed. All the dead cells of each line showed characteristics of apoptosis, which might be due to inhibition by EGCG of growth factors' signaling. Besides anticarcinogenic activity, EGCG is expected to have a new function for leukemia therapy without side effects.

In the present study we have focused mainly on the role of IL (interleukin)-10 in the crossregulation of prostaglandins and cytokines in human monocytes. We first determined the effects of tumor necrosis factor-α (TNF-α) and IL-10 on monocyte prostaglandin E2 (PGE2) production. Unstimulated monocytes constitutively produced a small but significant amount of PGE2 in the culture supernatants. Both TNF-α and lipopolysaccharide (LPS) caused a remarkable increase in monocyte PGE2 production. On the other hand, IL-10 alone was without effect on constitutive PGE2 production but drastically inhibited LPS-induced PGE2 production in monocytes. Moreover, this inhibitory effect of IL-10 was not simply attributable to its inhibition of TNF-α production in LPS-stimulated monocytes. Next, we determined the effect of PGE2 on TNF-α mRNA expression in monocytes. Treatment of monocytes with or without PGE2 showed no detectable TNF-α mRNA. Activation of monocytes by LPS resulted in a remarkable accumulation of TNF-α mRNA and PGE2 efficiently inhibited this expression. Finally, we determined the effect of PGE2 on IL-10 mRNA expression in monocytes. Similar to TNF-α mRNA, unstimulated monocytes showed no detectable IL-10 mRNA. Interestingly, PGE2 alone drastically induced IL-10 mRNA. Besides, activation of monocytes by LPS resulted in a remarkable accumulation of IL-10 mRNA, and PGE2 further enhanced this expression. These results indicate that TNF-α and PGE2 are key molecules for the induction of IL-10 in monocytes, and that IL-10, in turn, plays a crucial role in terminating the inflammatory cascade via downregulation of production of proinflammatory molecules including TNF-α and PGE2.

Interleukin-4 (IL-4) and IL-13 are functionally similar cytokines. The functional IL-4 receptor (IL-4R) consists of the IL-4R alpha chain (IL-4R alpha) and the IL-2R gamma chain (gamma c), which is shared by the IL-2, IL-7, IL-9, and IL-15 receptors. The functional IL-13R is thought to involve the IL-4R alpha but not gamma c. In this study, we have analyzed activation of members of the Janus tyrosine kinase (Jak) family and signal transducers and activators of transcription (STAT) 6 induced by IL-4 and IL-13 in Epstein-Barr virus-transformed B cells derived from two patients of X-linked severe combined immunodeficiency, who have mutations of the gamma c gene in the extracellular and intracellular domains. In these B cells, IL-4 failed to induce tyrosine phosphorylation of Jak3 and activation of STAT6, or activation of these molecules was significantly decreased compared with Epstein-Barr virus-transformed normal B cells. In contrast, IL-13 activated STAT6 in these cells as well as normal B cells. However, Jak3 was not activated by IL-13, even in normal B cells. These results clearly indicated that gamma c is essential for activation of Jak3 and STAT6 in the signal transduction pathway of IL-4 in human B cells and that IL-13 does not utilize gamma c but activates STAT6 through an alternative pathway, which is not impaired in B cells of X-linked severe combined immunodeficiency patients.

Recombinant human interleukin-10 (hIL-10) inhibited the formation of osteoclast-like multinucleated cells in rat whole bone marrow cultures. The effect of hIL-10 on the process of osteoclast formation was further examined, since the process of osteoclast formation includes the proliferation and the differentiation of osteoclast progenitors into mononuclear preosteoclasts and the fusion of preosteoclasts into multinucleated osteoclasts. In the nonadherent bone marrow cell culture system, which was free of stromal cells and formed preosteoclast-like cells, hIL-10 significantly inhibited the formation of preosteoclast-like cells even at a very low concentration (0.5 U/ml). The strong inhibition appeared even after treatment with hIL-10 for only the first 24 h of the culture. However, hIL-10 did not affect the fusion process of preosteoclast-like cells to form osteoclast-like multinucleated cells in the rat coculture system of preosteoclast-like cells with primary osteo-blasts. Furthermore, hIL-10 completely inhibited the colony formation induced by granulocyte macrophage colony-stimulating factor (GM-CSF). These findings suggest that the inhibition of osteoclastogenesis by hIL-10 started at the early stage of the differentiation of osteoclast progenitors to preosteoclasts. © 1995 Wiley-Liss Inc.

Band 3 is the major membrane protein of erythrocytes, which binds membrane skeletal proteins, glycolytic enzymes, and hemoglobin and transports various kinds of anions. Band 3-Memphis is a variant of Band 3, the amino terminal fragment of which depicts a slow electrophoretic mobility on sodium dodecyl sulfate-polyacrylamide gel. The frequency of Band 3-Memphis varies among populations, with a higher frequency among the Japanese. We investigated the frequency of Band 3-Memphis in a western Japanese island which is relatively isolated from the main islands, finding that the frequency of Band 3-Memphis of the inhabitants of this island is significantly higher than the frequency of the Japanese based on the survey in Kyushu Island. This indicates that there may be differences of population in the frequency of Band 3-Memphis in Japan and that Band 3-Memphis may be a good marker to genetically differentiate each population.

Both interleukin-10 (IL-10) and IL-4 inhibited the prostanoid synthesis of lipopolysaccharide (LPS)-stimulated human monocytes, and their inhibition was shown to be based on a common mechanism to suppress the gene expression of inducible cyclooxygenase (COX). COX has been shown to exist in at least two distinct isoforms, designated COX-1 and COX-2, and their gene expressions exhibit different profiles. At both the protein and mRNA levels, the expression of COX-1 was constitutive and was not modulated by treatments with LPS, IL-10, or IL-4. In contrast, the expression of COX-2 was observed only after stimulation with LPS. IL-10 and IL-4 significantly inhibited LPS-induced COX-2 expression. Kinetic studies showed that they inhibited COX-2 mRNA expression within 1 hour after stimulation and that maximal inhibition was consistently observed at 5 hours. Moreover, the addition of cycloheximide (CHX) to LPS-stimulated monocytes resulted in a superinduction of COX-2 mRNA, whereas CHX almost abrogated the abilities of IL-10 and IL-4 to inhibit this gene expression. Experiments with actinomycin D showed that both cytokines accelerated the degradation of COX-2 mRNA. Furthermore, nuclear run-on experiments showed that both cytokines modestly inhibited LPS-induced COX-2 gene transcription. Thus, both cytokines seemed to regulate the COX-related pathway in a similar manner, although their receptor systems did not show any structural similarities. Considering recent findings showing that the drugs that exhibit a selective effect on COX-2 may be more preferable in inflammatory conditions, such biologic activities of IL-10 and IL-4 described above may offer useful tools in controlling inflammatory disorders in the future.

Since IL-10 has recently been shown to exhibit pleiotropic effects on human monocytes, it was of interest to determine the effect of this cytokine on prostaglandin E2 (PGE2) production by monocytes. Recombinant IL-10 (rIL-10) did not significantly affect PGE2 production by lipopolysaccharide (LPS)-unstimulated monocytes, but efficiently inhibited PGE2 production by LPS-stimulated monocytes. The inhibition by rIL-10 was achieved in a dose-dependent manner. Recombinant IL-4 also inhibited PGE2 production at the same degree as rIL-10. Viral IL-10 inhibited PGE2 production by monocytes in a similar fashion as did human rIL-10. Endogenously produced IL-10 was also shown to inhibit PGE2 production by LPS-stimulated monocytes. Kinetic studies showed that the inhibition by rIL-10 on PGE2 production was observed at least 3 h after LPS stimulation. Taken together, these results indicate that IL-10 may play an important role in modulating immunological responses via down-regulation of PGE2 production by monocytes.

Recent advances have established that intralaminar and interlaminar excitatory networks between neocortical pyramidal cells are specialized into subnetworks. Here, we have investigated how the commissural system organizes the intracortical excitatory subnetworks to communicate between cortical hemispheres. Whole-cell recordings were obtained from callosal projection neurons [commissural (COM) cells], identified byin vivoinjection of retrograde fluorescent tracer into one hemisphere, in rat frontal cortical slices. We found that layer V (L5) COM cells were heterogeneous in physiological and morphological properties that correlated with projection patterns to contralateral and ipsilateral cortical areas. The probability of synaptically connected pairs of L5 COM cells was higher in cell pairs of the same firing subtypes than that in different cell subtype pairs. In interlaminar connections, layer II/III (L2/3) COM cells preferentially innervated L5 COM cells. Moreover, pairs of the same L5 COM subtypes were more likely to share inputs from L2/3 COM cells than were different COM subtype cell pairs. In addition, common inputs from L2/3 COM cells were frequently observed in L5 pairs of corticopontine cells and given firing subtypes of COM cells. Our results suggest that callosal communications are achieved via several distinct COM cell subnetworks differentiated according to the ipsilateral corticocortical and subcortical projection patterns.

Luminescent polymer nanocomposites were prepared from dye containing copolymers and inorganic nanocrystals. As a model material, 8-hydroxyquinoline containing poly(methyl methacrylate) with zirconium oxide nanocrystals (ZrO2-NCs) was prepared by forming coordination complexes with the surface of the ZrO2-NCs. Fluorescence emission in the visible light region which was from zirconium quinolate on the ZrO2-NC surface was observed at room temperature under UV illumination. The ZrO2-NCs were well dispersed in the polymer matrix with crosslinking on the nanocrystal surfaces. The polymer nanocomposites had high photostability, thermal stability and enhanced mechanical properties compared to those of the neat zirconium complexes. The luminescent stability of the polymer nanocomposites was enhanced due to the 8-hydroxyquinoline ligands fixed between inorganic nanocrystals and polymer chains. This new concept, in which the dye was immobilized by an organic/inorganic sandwich structure, was suitable for obtaining highly stabilized luminescent nanocomposite materials.

Mouse endothelial-adipocyte cell line (14F1.1), which induces proliferation of mouse stem cells in culture, is also capable of supporting long-term survival in culture of human myeloid progenitor cells; colony forming unit-granulocyte/macrophage (CFU-GM) was recovered from cultures incubated with the 14F1.1 cell line after over a month of incubation. The CFU-GM population increased beyond the input number, whereas, in control cultures initiated without stromal cells, the number of progenitors gradually declined. Addition of a relatively low concentration of human colony-stimulating factors (CSFs) into the cultures promoted the formation of “cobblestone areas,” where mouse stroma and human hemopoietic cells closely interacted. 14F1.1 supernatant alone did not support the survival of human CFU-GM but synergized with the function of human granulocyte-macrophage colony-stimulating factor (GM-CSF) to stimulate adherent macrophage proliferation.

Levels of serum granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with various leukocyte disorders were estimated by enzyme-linked immunosorbent assay (ELISA). Some cases of acute myelogenous leukemia and aplastic anemia showed elevated serum levels of G-CSF and/or GM-CSF, whereas almost all of 23 healthy controls showed G-CSF and GM-CSF levels lower than 100 pg/ml. High levels of both types of CSF were noted in patients with granulocytosis due to infection. These levels became lower after resolution of the infection. Daily changes in serum CSF levels were also examined in a patient with autoimmune neutropenia, and it was found that the peripheral neutrophilic granulocyte count changed almost in parallel with the serum G-CSF level but not with GM-CSF, following the pattern with a delay of about 4-5 h, suggesting the possibility that G-CSF mainly regulates peripheral neutrophil circulation.

The 26S ribosomal RNA gene of Physarum polycephalum is interrupted by two introns, and we have previously determined the sequence of one of them (intron 1) (Nomiyama et al. Proc.Natl.Acad.Sci.USA 78, 1376-1380, 1981). In this study we sequenced the second intron (intron 2) of about 0.5 kb length and its flanking regions, and found that one nucleotide at each junction is identical in intron 1 and intron 2, though the junction regions share no other sequence homology. Comparison of the flanking exon sequences to E. coli 23S rRNA sequences shows that conserved sequences are interspersed with tracts having little homology. In particular, the region encompassing the intron 2 interruption site is highly conserved. The E. coli ribosomal protein L1 binding region is also conserved.

Plasma renin activity (PRA) and urinary electrolyte excretion were measured in 137 healthy children aged 6 to 14 years. Plasma aldosterone concentration (PAC) was measured in 52 of the children. Nocturnal 12-hour urine was collected in 110 of the children. Spot urine was collected on two occasions, once just before lying down, once after 90-min supine rest in another 27. Na/K ratio and fractional Na excretion rate (FENa) in 12-hour urine showed a significant inverse correlation with PRA or PAC. Na excretion (mmol/min, mmol/mmol creatinine), Na/K ratio and FENa in the spot urine following 90 min in a supine position showed a significant inverse correlation with PRA or PAC, but they failed to show a significant relationship to PRA or PAC in the spot urine preceding supine rest. A spot urine after 90 min in the supine position is collected easily and hence most appropriate to study the relationship between Na excretion and PRA or PAC clinically.

The complete nucleotide sequences of the 5.8S and 26S rRNA genes of Physarum polycephalum and the transcribed spacer between them were determined. Comparison of the sequences with those of the Escherichia coli 23S rRNA and yeast 26S rRNA genes showed that there are 16 highly homologous regions in the sequences of Physarum and E. coli and that eukaryotes have some eukaryote-specific extra sequences. The sequence immediately following the 5.8S-like region of E. coli 23S rRNA was found to be highly homologous to the 5' terminus of Physarum 26S rRNA, indicating that the eukaryote-specific 5.8S rRNA gene is derived from the 5'-terminal region of the prokaryote large rRNA gene.

The nucleotide sequence of Physarum polycephalum 5.8S rRNA gene and its flanking regions has been determined. The homologies of the 5.8S rRNA sequence with those of Saccharomyces, Chlamydomonas and Xenopus were 56%, 50% and 52%, respectively. In spite of these relatively low homologies, its possible secondary structure was very similar to those of other species.

UCHIYAMA, M., OTSUKA, T., SHIBUYA, Y. and SAKAI, K. Abnormal Sodium and Potassium Metabolism in Orthostatic Dysregulation in Childhood. Tohoku J. exp. Med., 1984, 144 (3), 327-328 - Serum sodium (Na) and potassium (K), 12- hr urine Na, K and Na/K ratio and fractional Na excretion rate (FENa) were examined in 142 children with orthostatic dysregulation (O.D.) aged 6 to 15 years. Serum K and FENa were significantly lower in children with O.D. than in normal children, conflicting with the results of low plasma renin activity and aldosterone concentration in children with O.D. which we had previously reported. This suggests that there might be excessive excretion of a mineralocorticoid other than aldosterone or that there might be abnormal regulation of Na and K metabolism by the renin-angiotensin-aldosterone system.

Fractional excretion of filtered sodium (FENa), plasma renin activity (PRA), urinary kallikrein excretion and main urinary metabolite of prostaglandin F2 alpha (PGF MUM) excretion were measured to evaluate the relationship between FENa and these hormonal factors in 33 healthy children aged 8 to 15 years. FENa showed a significant negative correlation with PRA and PGF MUM excretion (P less than 0.001, P less than 0.01, respectively), suggesting that PRA and PGF MUM are useful investigations in evaluating FENa. Especially PRA is often measured routinely and should be measured first, which may provide useful pathophysiological information on the genesis of abnormal FENa.

Plasma renin activity (PRA) was measured after various stimuli to evaluate a renin-stimulating test and to screen suppressed PRA in 60 children with labile hypertension aged 10 to 14 years. There was a significant difference between supine PRA and that after both standing (for 15 or 60 minutes) or frusemide administration (P less than 0.001, respectively); however, there was no statistical difference between the PRA while standing or after frusemide. Children who gripped a hand dynamometer for three minutes did not show any change in PRA. Standing upright for 15 minutes or supine rest for 90 minutes after the administration of frusemide i.v. are easily applicable to children and seem the most appropriate renin-stimulating test in childhood. No subjects showed suppressed PRA in this study.

The subthalamic nucleus (STN) plays a key role in motor control. Although previous studies have suggested that Ca2+ conductances may be involved in regulating the activity of STN neurons, Ca2+ channels in this region have not yet been characterized. We have therefore investigated the subtypes and functional characteristics of Ca2+ conductances in STN neurons, in both acutely isolated and slice preparations. Acutely isolated STN cells were identified by retrograde filling with the fluorescent dye, Fluoro-Gold. In acutely isolated STN neurons, Cd2+-sensitive, depolarization-activated Ba2+ currents were observed in all cells studied. The current-voltage relationship and current kinetics were characteristic of high-voltage–activated Ca2+channels. The steady-state voltage-dependent activation curves and inactivation curves could both be fitted with a single Boltzmann function. Currents evoked with a prolonged pulse, however, inactivated with multiple time constants, suggesting either the presence of more than one Ca2+ channel subtype or multiple inactivation processes with a single channel type in STN neurons. Experiments using organic Ca2+ channel blockers revealed that on average, 21% of the current was nifedipine sensitive, 52% was sensitive to ω-conotoxin GVIA, 16% was blocked by a high concentration of ω-agatoxin IVA (200 nM), and the remainder of the current (9%) was resistant to the co-application of all blockers. These currents had similar voltage dependencies, but the nifedipine-sensitive current and the resistant current activated at slightly lower voltages. ω-Agatoxin IVA at 20 nM was ineffective in blocking the current. Together, the above results suggest that acutely isolated STN neurons have all subtypes of high-voltage–activated Ca2+ channels except for P-type, but have no low-voltage–activated channels. Although acutely isolated neurons provide a good preparation for whole cell voltage-clamp study, dendritic processes are lost during dissociation. To gain information on Ca2+ channels in dendrites, we thus studied Ca2+ channels of STN neurons in a slice preparation, focusing on low-voltage–activated channels. In current-clamp recordings, a slow spike was always observed following termination of an injected hyperpolarizing current. The slow spike occurred at resting membrane potentials and was sensitive to micromolar concentrations of Ni2+, suggesting that it is a low-threshold Ca2+ spike. Together, our results suggest that STN neurons express low-voltage–activated Ca2+ channels and several high-voltage–activated subtypes. Our results also suggest the possibility that the low-voltage–activated channels have a preferential distribution to the dendritic processes.