Direct modification of spermatogonial stem cells using lentivirus vectors in vivo leads to efficient generation of transgenic rats / 亚洲男科学杂志(英文版)

Spermatogonial stem cells (SSCs) transmit genetic information to the next progeny in males. Thus, SSCs are a potential target for germline modifications to generate transgenic animals. In this study, we report a technique for the generation of transgenic rats by in vivo manipulation of SSCs with a high success rate. SSCs in juvenile rats were transduced in vivo with high titers of lentivirus harboring enhanced green fluorescent protein and mated with wild-type females to create founder rats. These founder rats expressed the transgene and passed on the transgene with an overall success rate of 50.0%. Subsequent generations of progeny from the founder rats both expressed and passed on the transgene. Thus, direct modification of SSCs in juvenile rats is an effective means of generating transgenic rats through the male germline. This technology could be adapted to larger animals, in which existing methods for gene modification are inadequate or inapplicable, resulting in the generation of transgenic animals in a variety of species.

Lamotrigine, an antiepileptic drug, inhibits 5-HT₃ receptor currents in NCB-20 neuroblastoma cells

Lamotrigine is an antiepileptic drug widely used to treat epileptic seizures. Using whole-cell voltage clamp recordings in combination with a fast drug application approach, we investigated the effects of lamotrigine on 5-hydroxytryptamine (5-HT)₃ receptors in NCB-20 neuroblastoma cells. Co-application of lamotrigine (1~300 µM) resulted in a concentration-dependent reduction in peak amplitude of currents induced by 3 µM of 5-HT for an IC₅₀ value of 28.2±3.6 µM with a Hill coefficient of 1.2±0.1. These peak amplitude decreases were accompanied by the rise slope reduction. In addition, 5-HT₃-mediated currents evoked by 1 mM dopamine, a partial 5-HT₃ receptor agonist, were inhibited by lamotrigine co-application. The EC₅₀ of 5-HT for 5-HT₃ receptor currents were shifted to the right by co-application of lamotrigine without a significant change of maximal effect. Currents activated by 5-HT and lamotrigine co-application in the presence of 1 min pretreatment of lamotrigine were similar to those activated by 5-HT and lamotrigine co-application alone. Moreover, subsequent application of lamotrigine in the presence of 5-HT and 5-hydroxyindole, known to attenuate 5-HT₃ receptor desensitization, inhibited 5-HT₃ receptor currents in a concentration-dependent manner. The deactivation of 5-HT₃ receptor was delayed by washing with an external solution containing lamotrigine. Lamotrigine accelerated the desensitization process of 5-HT₃ receptors. There was no voltage-dependency in the inhibitory effects of lamotrigine on the 5-HT3 receptor currents. These results indicate that lamotrigine inhibits 5-HT₃-activated currents in a competitive manner by binding to the open state of the channels and blocking channel activation or accelerating receptor desensitization.

The Change of Ginsenoside Composition in the Ginseng (Panax ginseng) Flower Buds by the Ultrasonication and Vinegar Process

The purpose of this study was to develop a new ginseng (Panax ginseng) flower buds extract with the high concentration of ginsenoside Rg3, Rg5, Rk1, Rh1 and F4, the Red ginseng special component. Chemical transformation from the ginseng saponin glycosides to the prosapogenin was analyzed by the HPLC. The ginseng flower buds were processed at the several treatment conditions of the ultrasonication (Oscillator 600W, Vibrator 600W) and vinegar (about 14% acidity). The result of UVGFB-480 was the butanol fraction of ginseng flower buds that had been processed with ultrasonication and vinegar for 480 minutes gained the highest amount of ginsenoside Rg5 (3.548%), Rh1 (2.037%), Rk1 (1.821%), Rg3 (1.580%) and F4 (1.535%). The ginsenoside Rg5 of UVGFB-480 was found to contain 14.3 times as high as ginseng flower buds extracts (GFB, 0.249%).

Novel Influenza A (H1N1)-Associated Acute Necrotizing Encephalopathy: A Case Report

Several cases of acute necrotizing encephalopathy (ANE) with influenza A (H1N1) have been reported to date. The prognosis of ANE associated with H1N1 is variable; some cases resulted in severe neurologic complication, whereas other cases were fatal. Reports mostly focused on the diagnosis of ANE with H1N1 infection, rather than functional recovery. We report a case of ANE with H1N1 infection in a 4-year-old Korean girl who rapidly developed fever, seizure, and altered mentality, as well as had neurologic sequelae of ataxia, intentional tremor, strabismus, and dysarthria. Brain magnetic resonance imaging showed lesions in the bilateral thalami, pons, and left basal ganglia. To our knowledge, this is the first report of ANE caused by H1N1 infection and its long-term functional recovery in Korea.

Reliability of Visual Classification of Sagittal Gait Patterns in Patients with Bilateral Spastic Cerebral Palsy

OBJECTIVE: To investigate the reliability of inspection-based classification of sagittal gait patterns in children with bilateral spastic cerebral palsy (CP). METHOD: Video clip recordings of gait patterns and sagittal kinematic data obtained by a computerized motion analysis system from 91 patients with bilateral spastic CP were reviewed. The abnormal gait patterns were classified into 4 groups using the method described by Rodda et al. Visual observation-based classification (visual classification) was compared with classification by 3D analysis-based methods (3D classification). The reliabilities of visual classifications made by an experienced physician and a trainee physician were analyzed. RESULTS: The consistency of inspection-based gait classification using kinematic data analysis was demonstrated by an experienced physician (Kappa coefficient (k)=0.67, p<0.001). However, the consistency was low for the trainee physician (k=0.37, p<0.001). Group III (apparent equinus) was commonly confused with group IV (crouch gait) by the trainee physician, resulting in lower agreement for those two evaluation groups than for other patterns. Video observation showed low reliability in comparisons made between the experienced and the trainee physician (k=0.37, p<0.001). CONCLUSION: There was substantial agreement of gait classification between video observation and kinematic data analysis by the experienced physician, but not by the trainee physician. Low reliability was also demonstrated for inspection-based gait classification.

Electrophysiological Characterization of AMPA and NMDA Receptors in Rat Dorsal Striatum

The striatum receives glutamatergic afferents from the cortex and thalamus, and these synaptic transmissions are mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and N-methyl-D-aspartate (NMDA) receptors. The purpose of this study was to characterize glutamate receptors by analyzing NMDA/AMPA ratio and rectification of AMPA and NMDA excitatory postsynaptic currents (EPSCs) using a whole-cell voltage-clamp method in the dorsal striatum. Receptor antagonists were used to isolate receptor or subunit specific EPSC, such as (DL)-2-amino-5-phosphonovaleric acid (APV), an NMDA receptor antagonist, ifenprodil, an NR2B antagonist, CNQX, an AMPA receptor antagonist and IEM-1460, a GluR2-lacking AMPA receptor blocker. AMPA and NMDA EPSCs were recorded at -70 and +40 mV, respectively. Rectification index was calculated by current ratio of EPSCs between +50 and -50 mV. NMDA/AMPA ratio was 0.20+/-0.05, AMPA receptor ratio of GluR2-lacking/GluR2-containing subunit was 0.26+/-0.05 and NMDA receptor ratio of NR2B/NR2A subunit was 0.32+/-0.03. The rectification index (control 2.39+/-0.27) was decreased in the presence of both APV and combination of APV and IEM-1460 (1.02+/-0.11 and 0.93+/-0.09, respectively). These results suggest that the major components of the striatal glutamate receptors are GluR2-containing AMPA receptors and NR2A-containing NMDA receptors. Our results may provide useful information for corticostriatal synaptic transmission and plasticity studies.

Forskolin Enhances Synaptic Transmission in Rat Dorsal Striatum through NMDA Receptors and PKA in Different Phases

The effect of forskolin on corticostriatal synaptic transmission was examined by recording excitatory postsynaptic currents (EPSCs) in rat brain slices using the whole-cell voltage-clamp technique. Forskolin produced a dose-dependent increase of corticostriatal EPSCs (1, 3, 10, and 30micrometer) immediately after its treatment, and the increase at 10 and 30micrometer was maintained even after its washout. When the brain slices were pre-treated with (DL)-2-amino-5-phosphonovaleric acid (AP-V, 100micrometer), an NMDA receptor antagonist, the acute effect of forskolin (10micrometer) was blocked. However, after washout of forskolin, an increase of corticostriatal EPSCs was still observed even in the presence of AP-V. When KT 5720 (5micrometer), a protein kinase A (PKA) inhibitor, was applied through the patch pipette, forskolin (10micrometer) increased corticostriatal EPSCs, but this increase was not maintained. When forskolin was applied together with AP-V and KT 5720, both the increase and maintenance of the corticostriatal EPSCs were blocked. These results suggest that forskolin activates both NMDA receptors and PKA, however, in a different manner.

Effects of Apigenin on Glutamate-induced Ca2+i Increases in Cultured Rat Hippocampal Neurons

Flavonoids have been shown to affect calcium signaling in neurons. However, there are no reports on the effect of apigenin on glutamate-induced calcium signaling in neurons. We investigated whether apigenin affects glutamate-induced increase of free intracellular Ca2+concentration ([Ca2+]i) in cultured rat hippocampal neurons, using fura-2-based digital calcium imaging and microfluorimetry. The hippocampal neurons were used between 10 and 13 days in culture from embryonic day 18 rats. Pretreatment of the cells with apigenin (1micrometerto 100micrometer for 5 min inhibited glutamate (100 micrometer 1 min) induced [Ca2+]i increase, concentration-dependently. Pretreatment with apigenin (30micrometer for 5 min significantly decreased the [Ca2+]i responses induced by two ionotropic glutamate receptor agonists, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA, 10 micrometer 1 min) and N-methyl-D-aspartate (NMDA, 100 micrometer 1 min), and significantly inhibited the AMPA-induced peak currents. Treatment with apigenin also significantly inhibited the [Ca2+]i response induced by 50 mM KCl solution, decreased the [Ca2+]i responses induced by the metabotropic glutamate receptor agonist, (S)-3,5-dihydroxyphenylglycine (DHPG, 100micrometer 90 s), and inhibited the caffeine (10 mM, 2 min)-induced [Ca2+]i responses. Furthermore, treatment with apigenin (30micrometer significantly inhibited the amplitude and frequency of 0.1 mM [Mg2+o-induced [Ca2+]i spikes. These data together suggest that apigenin inhibits glutamate-induced calcium signaling in cultured rat hippocampal neurons.

Fluoxetine Modulates Corticostriatal Synaptic Transmission through Postsynaptic Mechanism

Fluoxetine, widely used for the treatment of depression, is known to be a selective serotonin reuptake inhibitor (SSRI), however, there are also reports that fluoxetine has direct effects on several receptors. Employing whole-cell patch clamp techniques in rat brain slice, we studied the effects of fluoxetine on corticostriatal synaptic transmission by measuring the change in spontaneous excitatory postsynaptic currents (sEPSC). Acute treatment of rat brain slice with fluoxetine (10microM) significantly decreased the amplitude of sEPSC (84.1+/-3.3%, n=7), but did not alter its frequency (99.1+/-4.7%, n=7). Serotonin (10microM) also significantly decreased the amplitude (81.2+/-3.9%, n=4) of sEPSC, but did not affect its frequency (105.8+/-8.0, n=4). The effect of fluoxetine was found to have the same trend as that of serotonin. We also found that the inhibitory effect of fluoxetine on sEPSC amplitude (93.0+/-1.9%, n=8) was significantly blocked, but not serotonin (84.3+/-1.6%, n=4), when the brain slice was incubated with p-chloroamphetamine (10microM), which depletes serotonin from the axon terminals and blocks its reuptake. These results suggest that fluoxetine inhibits corticostriatal synaptic transmission through postsynaptic, and that these effects are exerted through both serotonin dependent and independent mechanism.

NMDA Receptor-dependent Inhibition of Synaptic Transmission by Acute Ethanol Treatment in Rat Corticostriatal Slices

The effects of ethanol on corticostriatal synaptic transmission were examined, using extracellular recording and analysis of population spike amplitudes in rat brain slices, to study how acute ethanol intoxication impairs striatal function. Ethanol caused a decrease in population spike amplitudes in a dose dependent manner (50~200 mM). Pretreatment with picrotoxin, a gamma-amino butyric acid (GABA)A receptor antagonist, increased the population spikes but ethanol (100 mM) was still effective in decreasing the population spikes under this condition. In the presence of (DL)-2-amino-5-phosphonovaleric acid (APV), N-methyl-D-aspartate (NMDA) receptor antagonist, the inhibitory action of ethanol on population spikes was not shown. These results suggest that ethanol inhibits the glutamatergic corticostriatal synaptic transmission through blockade of NMDA receptors.

Dopamine Modulates Corticostriatal Synaptic Transmission through Both D1 and D2 Receptor Subtypes in Rat Brain

Striatum has important roles in motor control, habitual learning and memory. It receives glutamatergic inputs from neocortex and thalamus, and dopaminergic inputs from substantia nigra. We examined effects of dopamine (DA) on the corticostriatal synaptic transmission using in vitro extracellular recording technique in rat brain corticostriatal slices. Synaptic responses were elicited by stimulation of cortical glutamatergic inputs on the corpus callosum and recorded in the dorsal striatum. Corticostriatal population spike (PS) amplitudes were decreased (39.4+/-7.9%) by the application of 100microM DA. We applied receptor subtype specific agonists and antagonists and characterized the modulation of corticostriatal synaptic transmission by different DA receptor subtypes. D2 receptor agonist (quinpirole), antagonist (sulpiride), and D1 receptor antagonist (SKF 83566), but not D1 receptor agonist (SKF 38393), induced significantly the reduction of striatal PS. Pretreatment neither with SKF 83566 nor sulpiride significantly affected corticostriatal synaptic inhibition by DA. However, the inhibition of DA was completely blocked by pretreatment with mixed solution of both SKF 83566 and sulpiride. These results suggest that DA inhibits corticostriatal synaptic transmission through both D1 and D2 receptors in concert with each other.

5-Hydroxytryptamine Inhibits Glutamatergic Synaptic Transmission in Rat Corticostriatal Brain Slice

Striatum is involved in the control of movement and habitual memory. It receives glutamatergic input from wide area of the cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from the raphe nuclei. In our study, the effects of 5-HT on synaptic transmission were studied in the rat corticostriatal brain slice using in vitro whole-cell recording technique. 5-HT inhibited the amplitude as well as frequency of spontaneous excitatory postsynaptic currents (sEPSC) significantly, and neither gamma-aminobutyric acid (GABA) A receptor antagonist bicuculline (BIC), nor N-methyl-D-aspartate (NMDA) receptor antagonist, DL-2-amino-5-phosphonovaleric acid (AP-V) could block the effect of 5-HT. In the presence non-NMDA receptor antagonist, 2, 3-dioxo-6-nitro-1, 2, 3, 4-tetrahydrobenxo[f] quinoxaline-7-sulfonamide (NBQX), the inhibitory effect of 5-HT was blocked. We also figured out that 5-HT change the channel kinetics of the sEPSC. There was a significant increase in the rise time during the 5-HT application. Our results suggest that 5-HT has an effect on both pre- and postsynaptic site with decreasing neurotransmitter release probability of glutamate and decreasing the sensitivity to glutamate by increasing the rise time of non-NMDA receptor mediated synaptic transmission in the corticostriatal synapses.

Genetics in Epilepsy / 대한소아신경학회지

No abstract available.

The association between dietary fat and body fat in obese adults

BACKGROUND: There are different opinions on whether the percentage of dietary fat is associated with the development of obesity and on it's treatment . In this country, dietary fat intake has been smaller compared to the Western countries. The purpose of this study was to find whether intake of dietary fat is related to percentage body fat in obese adults cross sectionally. METHODS: Nutrient intake from 24 hour dietary recall and percent body fat from bioelectrical impedance method were measured in 51 obese adults. Total energy intake was associated with intake of dietary fat and body size. Thus, the association of intake of dietary fat and three types of fat with percentage body fat were examined after adjustment for total energy intake by using 4 statistical models (standard multivariate model, and nutrient residual model, energy partition model, and multivariate nutrient density model). RESULTS: In all of these models, the results for types of fat and total fat showed similar results. Higher intake of total fat, saturated and polyunsaturated fat was associated with increased percentage body fat, while higher intake of monounsaturated fat was associated with decreased percentage body fat. CONCLUSION: We found positive association between dietary intake of fat and percentage body fat in obese adults. Our results suggest that reducing fat intake would be a helpful way to prevent and treat obesity in adults.

Study on the Attitude to Home Attendants System and Home Nursing Education of the Housewives in the City / 예방의학회지

This study was conducted in order to find out the attitude of housewives toward the home attendants system, the type of institute managing home attendants, the education for home attendants, the basic requisites for home attendants, and home nursing education, and identify the factors influencing on the housewives's attitude. The data were collected through questionnaires obtained from 401 housewives from March 1 to March 31, 1988. The results summarized were as follows; 1) 90.2 percent of total housewives favored the home attendants system, and housewives who had have their family member with health problem especially showed favorable response. 2) The favored types of institution managing home attendants appeared to be private social work agency(33.0%), half-private and half-public agency(32.2%), government agency(19.9%) and profit agency(2.2%). In particular, housewives who had experienced nursing favored half-private and half-public agency(37.6%). 3) As the basic requisites for home attendants, housewives wanted service attitude(37.2%), nursing education(34.4%) and nursing experience(28.4%). But, housewives with nursing experience favored nursing education rather than service attitude. 4) 91.1% of total housewives favored the home nursing education. In particular, housewives of high education level and nursing experience showed more favorable response to the home nursing education.

The Response to a Cholesterol-Lowering Diet Instructed by Physicians and Dieticians

BACKGROUND: This study was performed to compare the effectiveness of cholesterol-lowering diet therapy instructed by physicians with that instructed by dieticians using techniques that remove regression to the mean. METHODS: 118 patients who visited the office of Family Medicine department in Pusan Paik Hospital from February to November, 1996 and had serum total cholesterol(TC) concentrations greater or equal to 200mg/dL from two measurements were enrolled. The patients were divided into two groups randomly according to the cholesterol-lowering dietary education methods : the one was educated by physicians(Group I), and the other by dieticians(Group II). We evaluated the differences of lipid levels after education in consideration of regression to the mean. RESULTS: The mean reduction in TC concentrations achieved by dietary therapy was 10.7 % and 7.3%(without and with adjustment for regression to the mean) in Group I, and 9.8 and 6.5%(without and with adjustment, for regression to the mean) in Group II. The baseline TC concentrations and TC concentrations after dietary therapy were significantly different in individual group regardless of adjustment for regression to the mean. However, the reduction degrees of TC concentrations were not significantly different between two groups. CONCLUSIONS: The results indicate that even after adjustment for regression to the mean, dietary therapy will achieve the expected reduction. And it seems that the diet education by physicians will be effective as much as that by dieticians.

Clinical study of hypertensive diseases in pregnancy in Southwest region of Chonnam / 대한산부인과학회잡지

OBJECTIVE: The purpose of this study is to analyze the present conditions of hypertensive diseases in pregnancy so as to examine the differences between the urban and rural communities in the southwest region of Chonnam about prenatal care from 1996 to 2000. METHODS: We analyzed the clinical characteristics of only 251 out of 13,296 pregnant women who were hospitalized to be delivered in Department of obstetrics and gynecology in the Mokpo Catholic Hospital for the past five years from 1996 to 2000. RESULTS: The incidence of hypertensive diseases in pregnancy was 1.89% of the total deliveries: mild preeclampsia (55.4%), severe preeclampsia (38.2%), eclampsia (1.2%) and chronic hypertension (5.2%). Hypertensive diseases in pregnancy was common in the age group of 25-29 years (45.9%) and in gestational age of 37-40 weeks was 67.3%. The rate of vaginal delivery was 49.0%: spontaneous delivery (33.5%), induced labor (15.5%) but the rate of cesarean section was 51%. As a maternal complications, anemia (55.7%) and postpartum hemorrhage (11.4%) were developed and fetus and neonatal complication due to intrauterine growth restriction showed a considerably high rate of 12.2%. Seen from the interrelation between a residential district and the frequency of prenatal care, 40.6% of pregnant women were undergone an prenatal care at most one time, especially 53.4% of reside in rural area (p.05). CONCLUSION: Not only a study of the cause and early diagnosis of hypertensive diseases in pregnancy, but also prenatal care, early checkup and education with keeping in close contact with an executive agency will lead to decrease newborn infant mortality and hypertensive diseases in pregnancy.

The effect of diet education provided by physicians and dieticians on serum lipid profiles during more than 1 year

BACKGROUND: The purpose of this study was to compare the long term effect of the cholesterol lowering diet education provided by physicians with the education provided by dieticians on serum lipid profiles of hypercholesterolemic patients. METHODS: Among 248 ambulatory patients who had mean baseline serum total cholesterol (TC) level > or = 200mg/dL and received cholesterol lowering diet education from physicians or dieticians, 41 patients who checked serum lipid profiles three times during the mean of 403 days after education were included as subjects. The differences in means of all serum lipid profiles associated with education methods after controlling for follow up duration, differences in means of all serum lipid profiles associated with follow up duration after controlling for education methods, any interaction between education methods and follow up duration on serum lipid profiles were analysed by using repeated measures of analysis of variance. The difference between the baseline lipid levels and the third lipid levels after education were analyzed by using Wilcoxon signed ranks tests in each group. Correlations between baseline serum lipid profiles and the last changes in serum lipid profiles were analyzed. RESULTS: There were no significant differences in means of all serum lipid profiles associated with education methods or follow up duration except LDL cholesterol (LDL C). The first LDL C level after education was significantly lower in the group educated by physicians compared with the baseline LDL C, but there was no such change in the group educated by dieticians. There were no interactions between education methods and follow up duration on all serum lipid profiles. The last change of total cholesterol in both groups and LDL C only in the group educated by dieticians were significant. Correlation coefficients between baseline triglyceride (TG) and change in TG, baseline LDL C and change in LDL C, baseline total cholesterol (TC) and change in TC in patients with TC > or = 240mg/dL were 0.500 (P=0.002), 0.597 (P<0.001), and 0.578 (P=0.001), respectively. CONCLUSION: The changes of serum lipid profile during more than 1 year after education were not significantly different according to diet education methods, but total cholesterol level was significantly decreased in both groups.

Artifacts by dental materials on magnetic resonance imaging

Magnetic resonance imaging(MRI)has proved to be a valuable method for evaluation of the head and neck. Unfortunately, metallic devices associated with certain dental fillings and applicances often cause variable artifacts that can obscure normal or pathologic conditions on MR and computed tomography. In this work, we assessed the MR appearance of dental prosthetic materials in vitro and in vivo including precious alloys. Nonprecions alloys, resin, amalgam and titanium alloy, For in vivo studies, these materials were placed in healthy volunteer's mouths and then images were assesed. Analyis of the appearance of shape and extent of artifact,and observed influence of these artifacts on the image interpretation at 0.2 Tesla permanent type MR scanner were valuated. Material used as temporary or permanent filling of crowns such as amalgam. precious alloy and, microfilled resin did not cause artifact on the image. The size of the artifact produced by the nonprecious alloys was influenced by the ferromagnetism of the object and the volume prosthesis, and was related to the scanning sequence. Nonprecious alloys produced minimal local signal distortions, where precious alloys, and dental resin had no effect on the MR image in vivo. These results were mainly from a low field strength MR scanner used in this study.

Inhibitory Modulation of 5-Hydroxytryptamine on Corticostriatal Synaptic Transmission in Rat Brain Slice

Striatum plays a crucial role in the movement control and habitual learning. It receives an information from wide area of cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from raphe nuclei. In the present study, the effects of 5-HT to modulate synaptic transmission were studied in the rat corticostriatal brain slice using in vitro extracellular recording technique. Synaptic responses were evoked by stimulation of cortical glutamatergic inputs on the corpus callosum and recorded in the dorsal striatum. 5-HT reversibly inhibited coticostriatal glutamatergic synaptic transmission in a dose-dependent fashion (5, 10, 50, and 100 microM), maximally reducing in the corticostriatal population spike (PS) amplitude to 40.1+/-5.0% at a concentration of 50 microM 5-HT. PSs mediated by non-NMDA glutamate receptors, which were isolated by bath application of the NMDA receptor antagonist, d, l-2-amino-5-phospohonovaleric acid (AP-V), were decreased by application of 50 microM 5-HT. However, PSs mediated by NMDA receptors, that were activated by application of zero Mg2+ aCSF, were not significantly affected by 50 microM 5-HT. To test whether the corticostriatal synaptic inhibitions by 5-HT might involve a change in the probability of neurotransmitter release from presynaptic nerve terminals, we measured the paired-pulse ratio (PPR) evoked by 2 identical pulses (50 ms interpulse interval), and found that PPR was increased (33.4+/-5.2%) by 5-HT, reflecting decreased neurotransmitter releasing probability. These results suggest that 5-HT may decrease neurotransmitter release probability of glutamatergic corticostriatal synapse and may be able to selectively decrease non-NMDA glutamate receptor-mediated synaptic transmission.