[Bioinformatics-based analysis of the effect of general Transcription Factor IIH on prognosis of Prostate cancer]

Objective: To investigate the genetic and expression characteristics of transcription factor IIH (TFIIH) in pre-initiationcomplex in prostate cancer (PCa) and its relationship with prostate cancer progression. Methods: Analyzing the expression characteristics and clinical signification of TFIIH subunits about 495 cases of PCa and 52 cases of adjacent cancer in The Cancer Genome Atlas-Prostate adenocarcinoma (TCGA-PRAD) database. PCa microarray chip was used to verify the correlation between the key factor General Transcription Factor IIH Subunit 4 (GTF2H4) in TFIIH and clinical features. Results: The 495 patients with PCa were (61.01±6.82) years old.The mRNA expression of ERCC3、GTF2H4 and MNAT1 were high in PCa tissues with GS≥8(P<0.05). The expression of GTF2H4 and MNAT1 were relevant to the pathological stages(P<0.05). High expression of GTF2H4 has higher biochemical recurrence (BCR) rate in PCa patients(HR=2.47, 95%CI:1.62-3.77, P<0.001), which has better predictive effect of BCR in PCa patients(The 3rd, 5th, and 7th year AUC all>0.7) than other subunits, and it has been verified in four additional databases. Single-factor Cox regression analysis showed that GTF2H4 were risk factors for BCR (HR=2.470, 95%CI:1.620-3.767, P<0.001) and GTF2H5 were protective factors(HR=0.506,95%CI: 0.336-0.762, P=0.001). The results of immunohistochemical staining showed that the protein expression of GTF2H4 was correlated with the clinical features of PCa patients.The differences of the above results were statistically significant. Conclusion: GTF2H4, the key factor of TFIIH, is highly expressed in PCa and indicates a poor prognosis.

[Anatomical characteristics of profunda artery perforator flap in the posteromedial femoral region and its application in the reconstruction of oral and maxillofacial defects]

Objective: To investigate the anatomical basis for the preparation of the profunda artery perforator flap (PAPF) in the posteromedial femoral region and its application in the reconstruction of oral and maxillofacial defects. Methods: Six lower limbs of Chinese adult cadavers were micro-surgically dissected. CT angiography (CTA) data of bilateral lower limbs of 6 patients was also collected retrospectively. The number, external diameter, pedicle length, and distribution of perforators in the posteromedial femoral region were recorded from the specimens and CTA data. Meanwhile, 10 patients with oral squamous cell carcinoma in the Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University from August 2018 to June 2021 were treated with the PAPF. At each follow-up, contour and function of recipient and donor site, as well as swallowing and speech function were evaluated. Results: A total of 19 profunda artery perforator were identified in 6 lower limb specimens. The outer diameter at the beginning of the source artery was (2.34±0.25) mm and the total length of the pedicle was (11.12±1.06) cm. CTA data analysis of 12 legs identified 15 perforators of profunda artery in the posteromedial region. Eleven perforators were septocutaneous, including 2 perforators with a common trunk, while the remaining 4 perforators were musculocutaneous. As for different patterns of perforators (septocutaneous perforators, musculocutaneous perforators and perforators with a common trunk), the longitudinal distance to the pubic tubercle was (19.95±2.43), (21.84±2.54) and (19.48±0.55) cm respectively. The horizontal distance to the posterior edge of gracilis was (3.54±1.10), (3.72±0.30) and (3.85±1.48) cm, respectively. The initial diameters of perforators was (2.4±0.4), (2.6±0.6) and 1.9 mm respectively. Ten cases of the profunda artery perforator flaps survived successfully after operation. The flap sizes ranged from 8 cm×6 cm to 12 cm×7 cm. The patients were evaluated at 1, 3 and 6 months, and with 6 months interval ever since. During the follow-up, the shape of the recipient site was ideal, and the swallowing and language functions were not significantly affected. There was only linear scar in the donor area, and the function of the thigh was basically normal. Conclusions: PAPF possessed a good anatomic stability, suitable vascular pedicle length and diameter, minor influence to the donor area, sufficient amount tissue with good quality. It is an ideal choice for head and neck reconstruction.

[Application and research progress of digital virtual simulated design in dental esthetic rehabilitation]

In dental esthetic rehabilitation, patients pay great attention to the rehabilitative esthetic effect before teeth preparation, and this is also an important content of doctor-patient communication. Along with the development and combined application of intraoral scan, three-dimensional (3D) face scan, digital design, numerical control machining and 3D printing technology, digital technology is gradually applied to the virtual simulated design before irreversible operation in dental esthetic rehabilitation. Digital technology can be used in dentistry to simulate the esthetic outcome in advance, to assist communication among the dentists, patients and dental technicians, and to realize satisfactory outcome in the final restorations precisely, which, as a result, increases the clinical satisfaction. This review focuses on the application of digital virtual simulated design technology in dental esthetic rehabilitation, analyzes the current research development, deficiency and future prospects, so as to provide guidance for clinical diagnosis and treatment.

[Activation of GPER inhibts proliferation and autophagy in prostatic epithelial cells]

Objective: To investigate the effect of G protein-coupled estrogen receptor (GPER) on proliferation and autophagy in prostatic epithelial cells. Methods: Cell Counting Kit-8 (CCK8) assay was used to observe the growth of BPH-1 and RWPE-1 cells after treating with or not with estradiol or GPER selective agonist G1. Autophagy was quantified with Western blot and Cyto-ID autophagy detection kit after treating with estradiol, G1 or both G1 and G15 in the same cells. Results: The OD value in estrogen group and G1 group was significantly lower than those in control group (P<0.01). Compared with control group, Western blot and Cyto-ID green reagent staining revealed that the ratio of LC3Ⅱ/LC3Ⅰ and the relative fluorescence intensity of BPH-1 and RWPE-1 cells were decreased in G1 group and estradiol group (P<0.01). Pretreatment with G15 reversed the effect of G1 (P<0.05). Conclusion: The activation of GPER leads to the inhibition of autophagy and cell proliferation.

[Effect of interleukin-6 promoter DNA methylation on the pathogenesis of systemic lupus erythematosus]

Objective: To analyze peripheral blood interleukin-6 (IL-6) promoter DNA methylation status and its clinical significance in patients with systemic lupus erythematosus (SLE). Methods: Blood samples of 41 adult patients with SLE and 20 healthy controls were collected.The methylation status of IL-6 promoter was determined by methylation specific polymerase chain reaction (MSP). The IL-6 expression was detected by real-time PCR.Correlations between IL-6 promoter methylation status and clinical features or laboratory findings in patients with SLE were analyzed. Results: The levels of IL-6 mRNA were significantly higher in peripheral blood of SLE.DNA methylation levels of IL-6 promoter were reduced in SLE patients as compared with healthy controls.The methylation status and expression of IL-6 in peripheral blood reflected the levels in peripheral blood mononuclear cells (PBMCs). Significantly positive correlation was found between IL-6 hypomethylation and renal disorder, as well as hypocomplementemia in patients with SLE. Conclusion: Hypomethylation of interleukin-6 promoter in peripheral blood might be involved in the etiology of SLE.

[Associations of obesity and physical activity with cognition in people aged 50 and above in Shanghai]

Objective: To investigate the associations of obesity and physical activity with cognition in the elderly. Methods: A cross-sectional survey was conducted from October 2009 to June 2010 among people aged ≥50 years selected through multistage random cluster sampling in Shanghai. The subjects' body weight, body height, waist circumference and hip circumference were measured to calculate body mass index (BMI) and waist-hip ratio (WHR), and the data on self-reported physical activity level were collected through questionnaire survey. A comprehensive battery of cognitive tests was conducted to assess subjects' cognitive functions, including verbal recall, forward digit span (FDS), backward digit span (BDS), and verbal fluency (VF). General linear model was used to examine the associations of BMI, WHR and physical activity with cognition. Results: A total of 7 913 participants were included, with a median age of 60 years. Age, sex, education level, income level, BMI, WHR and physical activity level were significantly associated with cognitive scores in univariate analysis. After adjusted for age, sex, education level and income level, BMI was no longer significantly associated with cognitive scores in all cognitive functions (all P>0.01). WHR was significantly associated with VF score (P<0.01). Abdominally obese participants had lower VF score than non-abdominally obese participants (P<0.01). Physical activity level was significantly associated with all cognitive functions (P<0.01). Compared with participants with moderate physical activity level, participants with low physical activity level had lower scores in all cognitive functions (P<0.01). Conclusion: Abdominal obesity and low physical activity level were negatively associated with cognition level in the elderly, suggesting that waist circumference control and physical activity might help maintain cognition in the elderly.

[The impact of weight management and related diuretic medication intervention based on body weight changes on cardiac function and re-hospitalization rate in patients with chronic congestive heart failure]

Objective: To explore the impact of weight management and related medication intervention based on body weight changes on cardiac function among patients with chronic congestive heart failure (CHF). Methods: Using prospective, randomized, controlled study methods, consecutive CHF patients, who hospitalized in our department from June 2014 to June 2016 (n=350), were randomly divided into intervention group (n=175) and control group (n=175). Patients in the intervention group received weight management guidance and the post discharge diuretic drugs regimen was adjusted based on body weight changes. The control group received routine medical care post discharge. Left ventricular ejection fraction (LVEF), B type natriuretic peptide precursor (NT-proBNP), 6 minutes walk distance and NYHA classification at one day before discharge and after 6 months were compared between the two groups respectively. Results: Follow-up visit data were not available from 6 patients in the control and intervention group respectively. NYHA classification, LVEF, NT-proBNP and 6 minutes walk distance were similar between the two groups at one day before discharge (all P>0.05). After 6 months, the LVEF and 6 minutes walk distance were significantly higher while NT-proBNP level was significantly lower in the intervention group compared to the control group (all P<0.01). Meanwhile, the LVEF and 6 minutes walk distance were significantly increased, while NT-proBNP was significantly reduced at 6 months post discharge compared to one day before discharge in the intervention group (all P<0.01). The LVEF was also significantly improved (P=0.035), but the NT-proBNP and 6 minutes walk distance were similar (P were 0.328 and 0.807 respectively) at 6 months after discharge compared to one day before discharge in the control group. The NYHA classification was significantly lower in intervention group and in control group at 6 months after discharge compared to one day before discharge (Z=5.154, P<0.01 and Z=10.497, P<0.01), and the NYHA classification improved more in the intervention group than in control group at 6 months after discharge (Z=9.235, P<0.01). The re-hospitalization rate of CHF patients in intervention group was 11.83% (20/169), which was significantly lower than the control group (33.14% (56/169), χ(2)=21.99, P<0.01). At 6 months follow up, body weight remained unchanged in the intervention group, while body weight tended to be higher in the control group compared to one day before discharge. Conclusion: The weight management and diuretic drug regimen adjudgment intervention based on body weight changes can improve cardiac function and reduced re-hospitalization rate in CHF patients.

Axonal regeneration by chronically injured supraspinal neurons can be enhanced by exposure to insulin-like growth factor, basic fibroblast growth factor or transforming growth factor beta

To test whether known growth factors could promote the regenerative reponse of chronically injured neurons, we exposed the injured adult rat spinal cord to insulin-like growth factor 1 (IGF-1), basic fibroblast growth factor (bFGF) or transforming growth factor beta 1 + 2 (TGFβs) 1 month after creation of a hemisection lesion. At 1 week later an autologous peripheral nerve graft was apposed to the rostral cavity wall and 1 month later Nuclear Yellow (NY) was used to retrogradely label neurons that had grown an axon into the graft. Neurons capable of axonal regeneration after a long term (5 weeks) injury were double labeled with True Blue (TB, provided at the time of hemisection lesion) and NY. Exposure to any of the three growth factors, compared to a PBS-treated control, resulted in a significant increase in the total number of regenerating supraspinal neurons, with the greatest increase after treatment with TGFβs. Treatment with TGFβs or bFGF led to a significant increase in the number of regenerating neurons in 6 out of 7 major regions (excluding the motor cortex) contributing to descending spinal pathways. Treatment with IGF-1 promoted significant regeneration only by reticular formation neurons. These results indicate that exposure to specific growth factors can enhance axonal regeneration by chronically injured neurons, thus overcoming one significant challenge to the repair of long standing structural damage to the spinal cord. © 1996 Elsevier Science Ireland Ltd. All rights reserved.

Single sevoflurane exposure decreases neuronal nitric oxide synthase levels in the hippocampus of developing rats

BACKGROUND

The use of general anaesthetics in young children and infants has raised concerns regarding the adverse effects of these drugs on brain development. Sevoflurane might have harmful effects on the developing brain; however, these effects have not been well investigated.

METHODS

Postnatal day 7 (P7) Sprague-Dawley rats were continuously exposed to 2.3% sevoflurane for 6 h. We used the Fox battery test and Morris water maze (MWM) to examine subsequent neurobehavioural performance. Cleaved caspase-3 and neuronal nitric oxide synthase (nNOS) were quantified by immunoblotting, and the Nissl staining was used to observe the histopathological changes in the hippocampus.

RESULTS

A single 6 h sevoflurane exposure at P7 rats resulted in increased cleaved caspase-3 expression and decreased nNOS levels in the hippocampus, and induced the loss of pyramidal neurones in the CA1 and CA3 subfields of the hippocampus at P7-8. These changes were accompanied by temporal retardation of sensorimotor reflexes. However, neither the Fox battery test at P1-21 nor the MWM test at P28-32 showed differences between the air- and sevoflurane-treated groups.

CONCLUSIONS

Although early exposure to sevoflurane increases activated caspase-3 expression and neuronal loss and decreases nNOS in the neonatal hippocampus, it does not affect subsequent neurobehavioural performances in juvenile rats.

Enhanced osseointegration of titanium implant through the local delivery of transcription factor SATB2

Titanium implants are widely used in dentistry and orthopedic surgery. Nevertheless, bone regeneration around the implant is a relatively slow process, after placement. This study assessed whether SATB2 can enhance osseointegration of a titanium implant. To determine the effect of SATB2 in implant integration, two different viruses encoding SATB2 (PBABE-Satb2 virus or RCAS-Satb2 virus) were locally administered to the bone defect prior to titanium implant placement in our established transgenic TVA mice. Seven and 21 days post implantation, the femurs were isolated for quantitative real-time RT-PCR, H&E staining, immunohistochemical (IHC) staining, and microcomputed tomography (microCT) analysis. Quantitative real-time RT-PCR results demonstrated that the in vivo overexpression of SATB2 enhanced expression levels of potent osteogenic transcription factors and bone matrix proteins. We also found that 21 days after implantation, there were no significant differences in the expression levels of SATB2, Osx, Runx2, COLI, OC, and BSP between the RCAS-Satb2 group and the RCAS group. Histological analysis showed that SATB2 overexpression significantly enhanced new bone formation and bone-to-implant contact after implantation. IHC staining analysis revealed that forced expression of SATB2 increased the number of BSP-positive cells surrounding the implant. MicroCT analysis demonstrated that in vivo overexpression of SATB2 significantly increased the density of the newly formed bone surrounding the implant. These results conclude that in vivo overexpression of SATB2 significantly accelerates osseointegration of titanium implants and SATB2 can serve as a potent molecule in promoting tissue regeneration.

Using tea stalk lignocellulose as an adsorbent for separating decaffeinated tea catechins

Lignocelluloses prepared from woody tea stalk, pine sawdust and sugarcane bagasse were used as adsorbents to isolate decaffeinated catechins from tea extracts and compared with synthetic macroporous resin HPD 600. HPD 600 had the highest adsorption capacity to catechins, followed by tea stalk lignocellulose while lignocelluloses of pine sawdust and bagasse the least. Tea stalk lignocellulose absorbed preferentially tea catechins and showed a good selectivity. HPD 600 absorbed caffeine and tea catechins simultaneously. The kinetics data of tea stalk lignocellulose showed a good fit with the Langmuir isotherm model. It is considered that tea stalk lignocellulose is an alternative low-cost adsorbent for preparing decaffeinated tea catechins.

The slow wave component of retinal activity in rd/rd mice recorded with a multi-electrode array

We investigated the differences in the retinal activity between normal and degenerate retina. Multi-electrode recordings were performed in in vitro mice retinas. Only short duration (<2 ms) retinal spikes were recorded in normal mice by postnatal day 28. However, in rd/rd mice, a slow wave component with approximately 100 ms duration was also recorded along with the spikes. We attempted to understand the mechanism of this slow wave component in degenerate retina by applying various synaptic blockers. With CNQX/AP-7, the glutamate antagonist (n = 7), the slow wave component disappeared while the normally less-dominant retinal spikes became more apparent. With strychnine, the glycine antagonist (n = 3) or picrotoxin, GABA antagonist (n = 3), the amplitude of the slow wave component increased. These suggest that a stronger excitatory glutamate input from bipolar cells to ganglion cells is the main contributor to this slow wave component in rd/rd mice.

Genistein directly blocks glycine receptors of rat neurons freshly isolated from the ventral tegmental area

The effects of tyrosine kinase inhibitors on the glycine-induced current (I(Gly)) were studied in rat neurons freshly isolated from the ventral tegmental area (VTA). Genistein reversibly and concentration-dependently depressed I(Gly), with an IC(50) of 13 microM. Preincubation with genistein had no effect on I(Gly), indicating that genistein is effective only when glycine is bound to the receptor and channels are most likely open. Genistein depressed maximum I(Gly) without significantly changing the EC(50) for glycine. Genistein-induced inhibition of I(Gly) was sensitive to membrane voltage, being greater at positive membrane potentials. A kinetic analysis indicated that genistein lengthens the time constant of I(Gly) activation, but has no effect on deactivation or desensitization. When genistein was rapidly washed out, a transient rebound current probably reflected a faster dissociation of genistein, with respect to glycine. Results of competition experiments suggest that genistein acts on the same region of the glycine receptor as picrotoxin. Daidzein, an analog of genistein that does not act on protein kinases, also inhibited I(Gly). Co-application of lavendustin A, a specific inhibitor of tyrosine kinase, had no effect on I(Gly). Our results extend to neurons isolated from the VTA, the previous finding that genistein directly inhibits glycine receptors of hypothalamic brain slices.

Decay of ethanol-induced suppression of glycine-activated current of ventral tegmental area neurons

We demonstrated previously that ethanol depresses glycine-induced currents in 45% of neurons freshly isolated from the ventral tegmental area (VTA) of rats (), and that protein kinase C (PKC) modulates this action of ethanol (). In the present study, we investigated the time course of this effect of ethanol on VTA neurons from young rats. For 70% of the neurons in which ethanol reduced glycine-evoked currents, this depressant effect gradually diminished during continuous superfusion with ethanol. Its action decayed faster when ethanol was applied in several brief pulses than by continuous superfusion. On the other hand, the decay was especially slower when ethanol was applied in pulses at longer intervals or by preincubation. Phorbol ester 12,13-dibutyrate (PDBu, 1 microM), an activator of PKC, also depressed glycine-induced currents. In approximately 40% (6/15) of the neurons, the effect of PDBu diminished with time and was antagonized by the specific PKC inhibitor, chelerythrine (7 microM). Chelerythrine also attenuated the ethanol-induced depression of glycine-induced currents and its time-dependent decay, thus confirming our previous evidence that PKC mediates, at least in part, the decay of the depressant effect of ethanol on glycine-induced currents of VTA neurons.

Ethanol inhibition of glycine-activated responses in neurons of ventral tegmental area of neonatal rats

The brain is particularly sensitive to alcohol during the period of its rapid growth. To better understand the mechanism(s) involved, we studied ethanol effects on glycine-activated responses of ventral tegmental area (VTA) neurons isolated from the newborn rat, using whole cell and gramicidin perforated patch-clamp techniques. Previously we reported that 0.1-40 mM ethanol enhances glycine-induced responses of 35% of VTA neurons. We now direct our attention to the inhibitory effects of ethanol observed in 45% (312 of 694) of neonatal VTA neurons. Under current-clamp conditions, 1 mM ethanol had no effect on the membrane potential of these cells, but it decreased glycine-induced membrane depolarization and the frequency of spontaneous action potentials. Under voltage-clamp conditions, 0.1-10 mM ethanol did not elicit a current but depressed the glycine-induced currents. The ethanol-induced inhibition of glycine current was independent of membrane potential (between -60 and +60 mV). Likewise, ethanol did not alter the reversal potential of the glycine-activated currents. Ethanol-mediated inhibition of glycine current depended on the glycine concentration. While ethanol strongly depressed currents activated by 30 microM glycine, it had no appreciable effect on maximal currents activated by 1 mM glycine. In the presence of ethanol (1 mM), the EC(50) for glycine increased from 32 +/- 5 to 60 +/- 3 microM. Thus ethanol may decrease the agonist affinity of glycine receptors. A kinetic analysis indicated that ethanol shortens the time constant of glycine current deactivation but has no effect on activation. In conclusion, by altering VTA neuronal function, ethanol-induced changes in glycine receptors may contribute to neurobehavioral manifestations of the fetal alcohol syndrome.

Ondansetron: a selective 5-HT(3) receptor antagonist and its applications in CNS-related disorders

Ondansetron is a selective 5-hydroxytryptamine(3) (5-HT(3)) receptor antagonist that has been introduced to clinical practice as an antiemetic for cancer treatment-induced and anesthesia-related nausea and vomiting. Its use under these circumstances is both prophylactic and therapeutic. It has a superior efficacy, safety and pharmacoeconomic profile compared with other groups of antiemetics, namely antidopaminergics, antihistamines and anticholinergics. However, its place in the management of anticipatory and delayed vomiting in cancer treatment and as a rescue antiemetic in surgical patients needs to be further explored. Furthermore, recent animal and human research also reflects its possible novel application in the treatment of other disease states, such as alcoholism, cocaine addiction, opioid withdrawal syndrome, anxiety disorders, gastrointestinal motility disorders, Tourette's syndrome and pruritus. This review revisits the widespread physiological and pathological effects of 5-HT and discusses both the basic science literature and the clinical developments responsible for the conventional and novel uses of ondansetron. In addition, new discoveries relating to the effects of ondansetron on other receptors/channels and their possible therapeutic applications are presented.

Interleukin-2 modulates N-methyl-D-aspartate receptors of native mesolimbic neurons

Interleukin (IL)-2 is a brain-derived cytokine that influences mesocorticolimbic dopamine release, and is associated with pathological outcomes that are mediated, at least in part, by aberrations in mesolimbic neurotransmission. The mechanisms by which IL-2 modulates mesolimbic transmission, however, are not known. The NMDA receptor/channel (NMDAR) plays an essential role in neuronal excitability of mesolimbic neurons; we thus examined in neonatal rats the effects of IL-2 on NMDA-activated current (I(NMDA)) in voltage-clamped neurons freshly isolated from the ventral tegmental area (VTA), the site of origin of the mesolimbic system. IL-2 (0.01-500 ng/ml) alone had no effect on membrane conductance. When co-applied with NMDA, IL-2 (50-500 ng/ml) significantly potentiated I(NMDA). In contrast, doses as low as 0.01 ng/ml markedly decreased the NMDA response. Dose-response analysis showed that IL-2 ( > 50 ng/ml) increased the maximal I(NMDA), without changing the EC(50), indicating that IL-2 potentiates I(NMDA) by increasing the efficacy of the NMDAR. Moreover, current-voltage analysis revealed that IL-2 potentiation of I(NMDA) was voltage-dependent, being greater at negative potentials. In contrast, IL-2 inhibition of I(NMDA) was voltage-independent, and IL-2 did not alter the reversal potential. Additionally, IL-2 (1 ng/ml) shifted the NMDA concentration-response curve to the right, significantly increasing the EC(50) for NMDA without changing the maximal I(NMDA), suggesting that IL-2 inhibits the NMDAR by a competitive mechanism. IL-2 thus acts as a potent modulator of the NMDAR. IL-2-induced alterations of responses to NMDAR activation may contribute to synaptic plasticity in the mesolimbic system and to pathological outcomes associated with this system.

Ethanol potentiation of glycine-induced responses in dissociated neurons of rat ventral tegmental area

The potentiation of glycine-induced responses by ethanol (EtOH) was studied in neurons freshly dissociated from the ventral tegmental area (VTA) of 5- to 14-day-old postnatal rats using whole-cell and gramicidin-perforated patch-clamp techniques. Under current-clamp conditions, EtOH increased glycine-induced membrane depolarization and action potential firing. Under voltage-clamp conditions, EtOH (0. 1-40 mM) alone did not elicit a current. When coapplied with glycine, EtOH enhanced the glycine-induced current in 35% (180 of 474) of the neurons. The EtOH-induced enhancement of glycine current was independent of membrane potential (between -60 and +60 mV); the reversal potential was not changed. Concentration-response analysis showed that in the presence of EtOH (10 mM), the EC(50) for glycine decreased from 25 +/- 4 to 14 +/- 3 microM; the Hill coefficient increased from 1.5 +/- 0.2 to 1.9 +/- 0.3. Kinetic analysis of glycine currents indicated that EtOH decreased the time constant of activation and increased the time constant of deactivation of glycine-gated chloride channels. EtOH may accelerate glycine association with its receptor at the agonist binding site and increase the apparent agonist affinity. Our observations suggest that, at pharmacologically relevant concentrations, EtOH alters the function of glycine receptors and thus the excitability of neonatal VTA neurons. This action of EtOH may contribute to the neurobehavioral disturbances associated with fetal alcohol syndrome.

Survival of chronically-injured neurons can be prolonged by treatment with neurotrophic factors

Axonal regeneration by chronically-injured supraspinal neurons can be enhanced by neurotrophic factor treatment at the site of injury, although the number of regenerating neurons decreases as the interval between spinal cord injury and treatment increases. This study investigated whether this decline in regenerative response could be due to continued loss of neurons during the post-injury period. Adult rats received a cervical hemisection lesion and axotomized neurons were labeled by retrograde transport of True Blue from the lesion site. Animals were killed one, four or eight weeks after injury and surviving neurons (True Blue-labeled) were counted in the red nucleus and lateral vestibular nucleus. The neuron number in the lateral vestibular nucleus was stable for eight weeks after spinal cord injury, while survival in the red nucleus decreased by 25% between four and eight weeks. To test how neurons respond to a second injury with or without trophic factor treatment, at four, eight, 14 or 22 weeks after injury the lesion cavity was enlarged by 0.5 mm in a rostral direction. Gel foam saturated with ciliary neurotrophic factor, brain-derived neurotrophic factor or basic fibroblast growth factor was placed into the cavity. Animals were killed four weeks later. Re-injury of the spinal cord caused a significant decrease in neuron survival in both the red nucleus and lateral vestibular nucleus, the effects of which were lessened by treatment with ciliary neurotrophic factor or brain-derived neurotrophic factor for the red nucleus and with ciliary neurotrophic factor for the lateral vestibular nucleus, when re-injured at four or eight weeks. Basic fibroblast growth factor did not affect neuron survival at any time post-injury. Ciliary neurotrophic factor was not effective with longer delays (14 or 22 weeks) between the initial injury and re-injury. These results indicate a delayed pattern of secondary neuronal cell loss after spinal cord injury that is exaggerated by re-injury, but which can be ameliorated by treatment with neurotrophic factors.

Waglerin-1 inhibits GABA(A) current of neurons in the nucleus accumbens of neonatal rats

The effect of Waglerin-1, a 22-amino acid peptide purified from the venom of Wagler's pit viper on the whole cell current response (I(GABA)) to gamma-aminobutyric acid (GABA) was examined for neurons freshly isolated from the nucleus accumbens of 3- to 7-day-old rats. Waglerin-1 depressed I(GABA) induced by subsaturating concentrations of GABA; the IC(50) for I(GABA) induced by 10 microM GABA was 2.5 microM Waglerin-1. This concentration of Waglerin-1 shifted the GABA concentration-response curve to the right in a parallel manner, increasing the GABA EC(50) from 12+/-3 to 27+/-5 microM. The depressant effect of Waglerin-1 was greater at negative holding potentials. Zn(2+) also inhibited I(GABA) with an IC(50) of 0.3 microM. Phosphorylation state appeared to modulate GABA(A) receptor sensitivity to the inhibitory effect of Waglerin-1 since dialysis of neurons with N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide HCl (H-89), an inhibitor of protein kinase A, prevented inhibition. The data are discussed in terms of developmental influences on the subunit composition of GABA(A) receptors in neurons of the nucleus accumbens.

Inhibitory effect of ondansetron on glycine response of dissociated rat hippocampal neurons

We examined the effect of ondansetron, an antagonist of type 3 serotonin receptors, on the whole cell response of freshly isolated hippocampal CA1 pyramidal neurons of neonatal and "mature" rats to glycine using the gramicidin perforated patch technique. Ondansetron depressed the current induced by subsaturating concentrations of glycine (IGly) in a concentration-dependent manner. The ondansetron concentration needed to depress IGly induced by 30 microM glycine to half amplitude was 25 microM. Ondansetron (54 microM) shifted the glycine concentration-response curve to the right in a parallel manner, increasing the EC50 for glycine from 40 +/- 3 microM to 70 +/- 5 microM. Ondansetron increased the time constant of activation of IGly without affecting the time constant of deactivation. When examined under current clamp conditions, glycine induced depolarization and hyperpolarization in neonatal and mature neurons, respectively; ondansetron also suppressed these responses to glycine. The data suggest that ondansetron competitively inhibits the glycine receptor.

Cocaine and lidocaine have additive inhibitory effects on the GABAA current of acutely dissociated hippocampal pyramidal neurons

Inhibition mediated by gamma-aminobutyric acid (GABA) is a major target for the central actions of cocaine and lidocaine, which can result in seizures, especially when these drugs are abused in combination. In the present study, we investigated how cocaine and lidocaine interact to depress GABA current (IGABA), recorded by the whole-cell technique in freshly isolated rat hippocampal neurons. Cocaine depressed IGABA in a concentration dependent manner, such that cocaine was more potent against lower than higher GABA concentrations: the cocaine IC50 was 0.13, 0.62 and 1.2 mM for GABA at 2, 10 and 100 microM, respectively. Cocaine depressed IGABA to the same extent in the absence and presence of 1 microM tetrodotoxin, indicating that cocaine inhibition of IGABA is distinct from its Na+ channel blocking action. Lidocaine reversibly depressed IGABA evoked by 10 microM GABA, with an IC50 of 9.8 mM. In the presence of 3 mM lidocaine, 0.3 mM cocaine depressed IGABA (10 microM GABA) to 30+/-7%. The significantly greater depression by the combined agents (p<0.05) indicates additive effects on the GABA receptor/channel complex, which are likely to contribute to the additive convulsant effects noted when these drugs are abused in combination.

Cocaine decreases the glycine-induced Cl- current of acutely dissociated rat hippocampal neurons

The effects of cocaine on glycine-induced Cl- current (I(GLY)) of single neurons, freshly isolated from the rat hippocampal CA1 area, were studied with conventional whole-cell recording under voltage-clamp conditions. Cocaine depressed I(GLY) in a concentration-dependent manner, with an IC50 of 0.78 mM. Preincubation with 1 mM cocaine alone had no effect on I(GLY), suggesting that resting glycine channels are insensitive to cocaine. The depression of I(GLY) by cocaine was independent of membrane voltage. Internal cell dialysis with 1 mM cocaine failed to modify I(GLY). Because the depression of I(GLY) was noncompetitive, cocaine may act on the glycine receptor-chloride ionophore complex at a site distinct from that to which glycine binds. The cocaine suppression of I(GLY) was unaffected by 1 microM tetrodotoxin and 1 microM strychnine. Blockers of protein kinase C (Chelerythrine), kinase A (N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide HCl, (H-89)) and Ca-calmodulin-dependent kinase (1-[N,O-bis(5-isoquinoline-sulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperaz ine (KN-62)) were also ineffective, which suggests that these phosphorylating mechanisms do not modulate cocaine-induced suppressant action on I(GLY). This extracellular, strychnine-independent depression of I(GLY) may contribute to cocaine-induced seizures.

cAMP-dependent protein kinase modulation of glycine-activated chloride current in neurons freshly isolated from rat ventral tegmental area

Adenosine 3',5'cyclic monophosphate-(cAMP)-dependent protein kinase (PKA) modulation of glycine-activated Cl- currents (IGly) in single neurons freshly isolated from the rat ventral tegmental area (VTA) was studied using whole-cell patch-clamp technique. In the majority of cells tested with Mg-ATP in the internal solution, IGly induced by 3-10 microM glycine increased spontaneously (ran up). In the absence of internal ATP, IGly remained stable in six of seven cells. External perfusion of 8-Br-cAMP, a PKA activator, potentiated IGly only in cells showing run-up. 8-Br-cAMP potentiated IGly induced by low concentrations of glycine, but had no effect on the maximal current. When added to the pipette solution, H-89, a PKA inhibitor, blocked ATP and 8-Br-cAMP induced run-up of IGly. In contrast, dialysis with chelerythrine, a PKC inhibitor, did not alter the run-up of IGly. These results suggest that the PKA pathway modulates the activity of the glycine receptor/channel complex via enhancing the affinity of the receptor for glycine.

Glycine-activated chloride currents of neurons freshly isolated from the ventral tegmental area of rats

Properties of whole-cell glycine currents (IGly) of ventral tegmental area (VTA) neurons from 3- to 7-day old Sprague-Dawley rats were investigated with the patch-clamp technique. Ninety-three percent of the 126 neurons examined produced IGly in response to glycine. For 70% of these neurons, IGly did not decay in response to a threshold concentration of glycine (1-5 microM). At elevated glycine concentrations, IGly consistently decayed from a peak to a steady state (SS). IGly increased in amplitude sigmoidally as a function of the concentration of agonist with an EC50 of 32 microM. Strychnine (STR), when co-applied with glycine after a prepulse of STR, suppressed both the peak and SS IGly noncompetitively. In the absence of a prepulse, STR had a smaller effect on peak IGly while increasing its decay rate; the SS amplitude decreased. These STR effects were concentration dependent with an IC50 of 31 nM and 184 nM STR for the peak and SS IGly, with prepulse, respectively, and 732 nM and 193 nM for the peak and SS IGly, respectively, without prepulse. Picrotoxin (PTX) co-applied with glycine suppressed both the peak and the SS IGly with an IC50 of 25 microM. In contrast to STR, 1 min preincubation with PTX had no effect on IGly. Thus, PTX acts on the open channel. The inhibitory effects of both STR and PTX on IGly did not depend on the membrane potential.

[Post-traumatic reconnection of the cervical spinal cord with skeletal striated muscles. Study in adult rats and marmosets]

In an attempt at repairing the injured spinal cord of adult mammals (rat, dog and marmoset) and its damaged muscular connections, we are currently using: 1) peripheral nerve autografts (PNG), containing Schwann cells, to trigger and direct axonal regrowth from host and/or transplanted motoneurons towards denervated muscular targets; 2) foetal spinal cord transplants to replace lost neurons. In adult rats and marmosets, a PNG bridge was used to joint the injured cervical spinal cord to a denervated skeletal muscle (longissimus atlantis [rat] or biceps brachii [rat and marmoset]). The spinal lesion was obtained by the implantation procedure of the PNG. After a post-operative delay ranging from 2 to 22 months, the animals were checked electrophysiologically for functional muscular reconnection and processed for a morphological study including retrograde axonal tracing (HRP, Fast Blue, True Blue), histochemistry (AChE, ATPase), immunocytochemistry (ChAT) and EM. It was thus demonstrated that host motoneurons of the cervical enlargement could extend axons all the way through the PNG bridge as: a) in anaesthetized animals, contraction of the reconnected muscle could be obtained by electrical stimulation of the grafted nerve; b) the retrograde axonal tracing studies indicated that a great number of host cervical neurons extended axons into the PNG bridge up to the muscle; c) many of them were assumed to be motoneurons (double labelling with True Blue and an antibody against ChAT); and even alpha-motoneurons (type C axosomatic synapses in HRP labelled neurons seen in EM in the rat); d) numerous ectopic endplates were seen around the intramuscular tip of the PNG. In larger (cavitation) spinal lesions (rat), foetal motoneurons contained in E14 spinal cord transplants could similarly grow axons through PNG bridges up to the reconnected muscle. Taking all these data into account, it can be concluded that neural transplants are interesting tools for evaluating both the plasticity and the repair capacities of the mammalian spinal cord and of its muscular connections.

Ondansetron exhibits the properties of a local anesthetic

The purpose of this study was to determine whether ondansetron (OND) has local anesthetic effects. Using a patch-clamp technique, we showed that OND concentration dependently blocked Na channel currents in freshly isolated neurons of rat brains with a 50% inhibition concentration of 12 microM. The blockade started immediately when OND was applied to the cell body using a fast perfusion system, reached a plateau within 15 s, and recovered to the control level within 30 s after washout of the OND-containing solution. Because this is a known property of local anesthetics, we used the tail-flick technique to verify this effect in vivo in Sprague-Dawley rats (n = 46). OND was injected subcutaneously into the tail at the doses of 0.08, 0.16, and 0.2 mg. The tail-flick latency increased 2 min after OND injection, reaching the plateau within 5 min. This effect was dose-related, lasting from 10 to 25 min. These preliminary data indicate that OND, a selective 5-HT3 receptor antagonist, might serve as a prototype molecule for development of a novel series of local anesthetics.

IMPLICATIONS

Ondansetron is a drug used to prevent vomiting, especially in cancer patients after chemotherapy. We found that it also causes numbness when injected under the skin. This new action may contribute to its role in "calming the stomach." We studied the effect of ondansetron on the isolated brain cells of live rats.

Ondansetron modulates GABA(A) current of rat central nervous system neurons

We examined the effect of ondansetron, a 5-HT3 receptor antagonist, on the whole cell current response of freshly isolated hypothalamic and hippocampal neurons of rats to gamma-aminobutyric acid (GABA). The nystatin perforated patch technique was used to minimize run-down of the GABA current. While 1-150 microM ondansetron had no effect on membrane conductance, co-application with agonist reversibly depressed the maximal end GABA current. The concentration-response relation of GABA reveals a non-competitive mechanism. However, the inhibitory effect was more potent when ondansetron was co-applied with lower concentrations of GABA: i.e., the ondansetron concentration needed to depress the current induced by 5 microM GABA to half amplitude was 7 microM compared to 28 microM for the current induced by 10 microM GABA. Analysis of the current-voltage relationship with and without ondansetron indicated that the effect of ondansetron is not voltage dependent. Current-voltage relations also showed that the effect of ondansetron was not due to activation of a GABA-independent current because the reversal potentials were the same with and without ondansetron. The present data suggest that ondansetron's suppression of GABA-activated current may be the molecular basis of ondansetron-induced seizures observed in vivo.

Cocaine depresses GABAA current of hippocampal neurons

Although blockade of dopamine re-uptake and the resulting elevation of excitatory agonists is commonly thought the primary mechanism of cocaine-induced seizures, it is possible that other neurotransmitters such as gamma-aminobutyric acid (GABA) are involved. To examine this possibility, the effects of cocaine on the whole cell GABA current (IGABA) of freshly isolated rat hippocampal neurons were investigated with the patch-clamp technique. Preincubation or acute application of cocaine reversibly suppressed IGABA. The IC50 was 127 microM when cocaine was applied before the application of GABA. The concentration-response relations of cocaine in various GABA concentrations revealed that cocaine inhibited IGABA non-competitively. This effect of cocaine appeared to be independent of voltage. The present study suggests that the GABA receptor/channel complex is also a target for cocaine's action. The suppression of IGABA may contribute to cocaine-induced seizures.

Waglerin-1 modulates gamma-aminobutyric acid activated current of murine hypothalamic neurons

We examined the effect of Waglerin-1, a peptide of 22 amino acid residues purified from the venom of Wagler's pit viper (Trimeresurus wagleri), on the whole cell current response (I(GABA)) of freshly isolated murine hypothalamic neurons to gamma-aminobutyric acid (GABA). Although the application of 32 microM Waglerin-1 alone had no effect on membrane conductance, coapplication with GABA increased I(GABA) for 78 and suppressed I(GABA) for 44 of the 141 neurons examined. The potentiating effect of Waglerin-1 was associated with a leftward shift of the concentration-response relation of GABA without increasing peak I(GABA). This potentiating effect of Waglerin-1 on I(GABA) mimics diazepam. Furthermore, the benzodiazepine antagonist flumazenil antagonized Waglerin-1 potentiation of I(GABA), These observations suggest that Waglerin-1 acts on the benzodiazepine site of one type of GABA(A) receptor/channel complex to increase its affinity for agonist. In contrast, the depressant effect of Waglerin-1 was associated with a rightward shift of the concentration-response relation of GABA without depressing the maximal I(GABA); this suggests a competitive inhibition of a second class of GABAR. The ability of Waglerin-1 to suppress I(GABA) showed a positive correlation with a similar action of Zn++. As with Zn++, the depressant effect of Waglerin-1 on I(GABA) was more pronounced at negative holding potentials. These observations are discussed in terms of variation in the subunit composition of GABA receptors that murine central nervous system neurons express.

Changes occur in the ability to promote axonal regeneration as the post-injury period increases

This study tested whether adult rat brain stem neurons could respond to growth or trophic factors provided after an extended post-injury period. The number of neurons that regenerated their axon into a peripheral nerve graft following exposure to ciliary neurotrophic factor (CNTF) 8 weeks after a cervical lesion was comparable to the number regenerating after exposure to CNTF 4 weeks after injury. In contrast, there was a significant decrease of 50% in the number of regenerating neurons following exposure to basic fibroblast growth factor (bFGF) 8 weeks after injury compared with the number regenerating after treatment with bFGF 4 weeks after injury. These results indicate that some factors are effective promoters of regeneration only if provided within a defined post-injury period.

Treatment of the chronically injured spinal cord with neurotrophic factors can promote axonal regeneration from supraspinal neurons

Axonal regeneration has been demonstrated by supraspinal neurons long after a spinal cord injury, although this potential seems limited to a few neurons in specific nuclear groups. Whether the regenerative response could be enhanced by exposure to neurotrophic factors was examined in this study. Neurons injured during a cervical spinal cord hemisection lesion were labeled with true blue (TB). Four weeks after spinal cord injury, gel foam saturated with brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), ciliary neurotrophic factor (CNTF), or saline as a control was placed into the lesion cavity. The gel foam was replaced with fresh factor after 3 days, and 4 days later a peripheral nerve (PN) graft was apposed to the rostral cavity wall. Four weeks later neurons that grew an axon into the PN graft were labeled with nuclear yellow (NY). Cells that were double labeled (TB and NY) represented chronically injured neurons capable of axon regeneration. Cells labeled with NY only were either acutely injured neurons capable of axonal regrowth or uninjured neurons that had sprouted into the PN graft. The total number of TB/NY-labeled neurons was significantly increased following exposure to BDNF, NT-3, or CNTF. Specific regions most influenced by NT-3 and BDNF were the reticular formation and red nucleus. Treatment with CNTF resulted in a significant increase in most brain regions with a major contribution to descending pathways in the spinal cord, the motor cortex being the exception, with no evidence of axonal regeneration by neurons forming the corticospinal tract. The total number of NY-only labeled neurons also was significantly greater after treatment with BDNF or CNTF. These results demonstrate the potential to increase the regenerative response of specific chronically injured supraspinal neurons by application of neurotrophic factors to the injury site.

2,3-Butanedione monoxime modifies the glycine-gated chloride current of acutely isolated murine hypothalamic neurons

In this study, we explored the effect of the chemical phosphatase 2,3-butanedione monoxime (BDM) on glycine current (IGly) of murine ventromedial hypothalamic neurons. Co-application of 0.01 to 67 mM BDM increased IGly decay rate with little change of the peak amplitude. This effect was both rapid in onset and offset and required the presence of the agonist. Pretreatment with BDM alone did not alter-IGly decay. In addition, dialysis of neurons with 500 microM ATP-gamma-S did not alter the acute effect of BDM. Thus, this effect may result from open channel block rather than BDM-induced dephosphorylation of the receptor/channel protein. In contrast to the acute effect described above, relatively prolonged (i.e., greater than 80 s) pretreatment with BDM reduced peak IGly. The phorbol ester (PDBu), a protein kinase C (PKC) activator, mimicked this effect of BDM. Furthermore, chelerythrine, a specific PKC inhibitor, prevented this effect of BDM on peak IGly. Thus, activation of PKC may mediate this attenuating effect of BDM on IGly. For a sub-population of these pretreated neurons, there was a subsequent potentiation of IGly which followed the initial suppressant effect. This potentiation may be due to a phosphatase effect of BDM, since it was observed more frequently when neurons were also pretreated with the protein kinase inhibitors H7 or chelerythrine. These findings suggest that BDM alters protein kinase activity and acts as a phosphatase to regulate the activity of the glycine receptor/channel complex.

Motoneurons of the injured spinal cord of the adult dog can grow lengthy axons into an autologous peripheral nerve graft. A retrograde axonal tracing study

To our knowledge, the capacity of injured spinal neurons to regenerate axons into peripheral nerve autografts has not yet been documented with axonal tracing methods in large adult mammals such as dogs. In the present study, one end of an autologous peripheral nerve graft (PNG), 10-15 cm long, was introduced dorsally into the lumbar (L4) spinal cord of six adult beagle dogs, thus producing a small focal lesion. The other end of the PNG was driven outside the spinal cord, then crushed and tied to nearby peripheral tissue with non-absorbable suture. Clinical examination of the operated animals was performed throughout the postoperative period. In five animals (out of six), the neurological deficit induced by the grafting procedure disappeared within five days. Four months after surgery, application of horse radish peroxidase (HRP) to the transected peripheral tip of the PNG led to the retrograde axonal labelling of about 30 lumbar neurons. The labelled cells, which had extended lengthy (up to 10 cm) axons into the PNGs, were mainly located in the vicinity of the intraspinal tip of the grafted nerve. Upon specific criteria, most of them were characterized as motoneurons. As the surgical procedure probably left the original stem axon of these neurons uninjured, it is suggested that axonal production from the labelled motoneurons might have arisen either from collateral axonal sprouts or even directly from the neuronal soma.

Excitatory amino acid induced currents of isolated murine hypothalamic neurons and their suppression by 2,3-butanedione monoxime

Ionic currents induced by excitatory amino acids were investigated for freshly isolated murine hypothalamic neurons with whole cell recording techniques. L-glutamate or N-methyl-D-aspartate (NMDA), in combination with glycine, resulted in a rapidly rising current which decayed in the continued presence of agonist. In contrast, kainate currents did not decay. While quisqualate-induced current maintained a steady amplitude in the continued presence of agonist, a rapid decay phase appeared at holding potentials negative to -50 mV. Co-application of 2,3-butanedione monoxime (BDM) reversibly inhibited the currents due to each agonist. Detailed study of BDM suppression of kainate-induced current revealed two components. A component with a rapid onset did not involve phosphatase action since 500 microM ATP-gamma-S or a protein kinase inhibitor (H-7, 200 microM) did not alter current suppression or recovery after BDM. Thus, the probable mechanism for this component of BDM's effect is direct block of the kainate-activated ion channel. However, preincubating neurons with 30 mM BDM reduced their subsequent response to kainate alone. This persistent effect of BDM was not seen for neurons dialyzed with a solution containing ATP-gamma-S during conventional whole cell recording. Furthermore, exposure to H-7 prevented recovery of the kainate response suppressed by preincubation in BDM. These findings suggest that BDM causes sustained suppression of the kainate response of hypothalamic neurons via a "chemical phosphatase" action.

2,3-Butanedione monoxime protects mice against the convulsant effect of picrotoxin by facilitating GABA-activated currents

While adult mice receiving picrotoxin (PTX) alone responded with clonic and tonic-clonic seizures, this response was greatly suppressed for mice simultaneously injected with 2,3-butanedione monoxime (BDM). For example, 60% and 10% of the mice convulsed when injected (i.p.) with 3.0 mg/kg PTX alone or PTX plus 205 mg/kg of BDM, respectively. In contrast, a non-oxime analogue of BDM, 2,3-butanedione (BTD), did not have this anticonvulsant effect. In order to explore the basis for the anticonvulsant effect of BDM, we recorded GABA-activated currents (IGABA) of frontal cortical as well as ventromedial hypothalamic neurons before, during and after exposure to this oxime. BDM had a biphasic effect on IGABA. That is, high concentrations (100 microM-40 mM) decreased and lower concentrations (0.01 microM-0.001 microM) potentiated IGABA; these effects of BDM reversed upon washout of the oxime. In contrast, BTD had no effect on IGABA. Finally, when 0.001 microM BDM, 10-30 microM PTX and GABA were co-applied the inhibitory effect of the toxin on IGABA was markedly suppressed. These data suggest that the anticonvulsant effect of oximes involves facilitation of the inhibitory action of GABA.

Persistence of functional neuromuscular junctions formed in a denervated skeletal muscle of the adult rat by axons that have regrown from the injured spinal cord through a peripheral nerve autograft

In previous 'short-term' (2 to 7 months) experiments, we had demonstrated, in the adult rat, that motoneurons of the injured cervical spinal cord could extend lengthy axons into an autologous peripheral nerve segment which was connected to a nearby denervated skeletal muscle. In addition, we had shown that new functional motor endplates were formed by these axons both at the original sites of innervation and at ectopic locations of the denervated muscle. This substitution motor system, although quite functional, was anatomically very different from the original model of innervation in the intact animal, relating to its motoneuronal pool, the course of its motor axons and the sites of terminal innervation. The present 'long-term' (11 to 21 months) experiments demonstrate the anatomical and functional permanency of the new motor circuitry, despite a lack of strict specificity in the new neuromuscular connections. However, some minor modifications or adjustments were observed with time: (i) the maintenance of functional ectopic endplates could be consistently demonstrated, while functional reinnervated endplates at the initial sites of innervation were rare or even lacking; (ii) there was a definitive withdrawal of all non target-specific regenerated axons from the vicinity of the muscle. It is now necessary to address the question to what extent this substitution motor system is actually controlled by central and/or peripheral inputs.

Calcium currents in pyramidal neurons acutely dissociated from the rat frontal cortex: a study by the nystatin perforated patch technique

We studied electrical and pharmacological properties of voltage-activated Ca2+ currents (ICa) in freshly dissociated rat frontal cortical pyramidal neurons by using nystatin perforated patch and conventional patch-clamp techniques. With either nystatin perforated patch technique or conventional patch-clamp technique, low voltage-activated ICa (LVA ICa) and high voltage-activated ICa (HVA ICa) were recorded. However, in conventional whole-cell recording, HVA ICa ran down within 5-20 min, whereas the current remained stable for 50 min at least in nystatin perforated patch recording. The HVA ICa recorded by nystatin perforated patch technique was further classified to L-type, N-type and a current component resistant to both nicardipine and omega-conotoxin by their current kinetics, voltage- and drug-sensitivities. Present results suggest that the perforated patch technique is a useful method for studying the properties of high voltage-activated Ca2+ channels.

Co-transplantation of fetal or adult dorsal root ganglia and of autologous peripheral nerve segments to the adult rat spinal cord: extensive reinnervation of the grafted nerves by the transplanted DRG cells

Intraspinal transplantation of embryonic neurons and of autologous peripheral nerve segments is an essential tool for studying plasticity and repair in the adult mammalian spinal cord. Unlike adult central nervous system neurons, adult dorsal root ganglion (DRG) cells can be cultured in vitro and are assumed to survive transplantation. In the present work, we have co-transplanted adult (and also fetal, for comparison) DRG and peripheral nerve autografts to the cervical spinal cord of the adult rat. Similar results were obtained from both series: fetal as well as adult DRG cells did survive transplantation and nearly half of them grew lengthy axons into the grafted nerves. A few of them were seen to express a calcitonin gene-related peptide. Possibilities of central afferentation as well as of peripheral connectivity of these transplanted neurons is under study.

Co-transplantation of embryonic neural tissue and autologous peripheral nerve segments to severe spinal cord injury of the adult rat. Guided axogenesis from transplanted neurons

The present study is the first of a series of experiments designed to investigate the possibilities of reconstructing the severely injured spinal cord by means of transplantation techniques. Special attention has been given here to the capability of transplanted embryonic neurons to extend axons into autologous peripheral nerve grafts (PNGs). A cavity, made unilaterally in the cervical enlargement of the spinal cord of adult rats, was filled with solid pieces of different embryonic tissues: spinal cord (SC), cortex (CT) or dorsal root ganglia (DRG). In more than half of the transplanted animals, one end of a PNG was inserted into the center of the transplants, while the other, extraspinal end, was crushed and tied to peripheral tissues. After a postgrafting period ranging from 1 to 6 months, we found that the 3 types of transplants in general had survived and become integrated with the host spinal cord, although their overall organization remained atypical. Surviving graft neurons had developed processes, some of which had become myelinated. The ability of the grafted neurons to extend axons into the PNG differed strikingly from one type of graft to another, being apparently non-existent for cortical grafts, moderate for spinal cord grafts and quite extensive for dorsal root ganglia transplants. Interestingly, these differences reflected what was observed for the corresponding, fully differentiated qeurons in adult animals, when their cut axons were put in contact with non-neuronal components of peripheral nerves.

Study on the Alkaloids of Melodinus tenuicaudatus

Fourteen alkaloids were isolated from the stem bark of MELODINUS TENUICAUDATUS Tsiang et P. T. Li. Eleven of them were identified as known alkaloids, namely, scandine ( 2), Delta (14)-eburnamine ( 4), vindolinine N(b)-oxide ( 5), 11-methoxytabersonine ( 6), vindolinine ( 7), EPI-vindolinine N(b)-oxide ( 8), hazuntine ( 9), compactinervine ( 10), 11-hydroxytabersonine ( 11), Delta (14)-vincine ( 12), and normacusine B ( 14). Two alkaloids were new: 10-hydroxyscandine ( 1), and the dimer, tenuicausine ( 3); their structures were elucidated by spectroscopic and chemical methods. One alkaloid ( 13) occurring in trace amounts, could not be identified.

Sequence analysis of cDNAs for the human and bovine ATP synthase beta subunit: mitochondrial DNA genes sustain seventeen times more mutations

We have cloned and sequenced human and bovine cDNAs for the beta subunit of the ATP synthase (ATP-syn beta), a nuclear DNA (nDNA) encoded oxidative phosphorylation (OXPHOS) gene. The two cDNAs were found to share 99% amino acid homology and 94% nucleotide homology. The evolutionary rate of ATPsyn beta was then compared with that of two mitochondrial DNA (mtDNA) ATP synthase genes (ATPase 6 and 8), seven other mtDNA OXPHOS genes, and a number of nuclear genes. The synonymous substitution rate for ATPsyn beta proved to be 1.9 x 10(-9) substitutions per site per year (substitutions x site-1 x year-1) (SSY). This is less than 1/2 that of the average nDNA gene, 1/12 the rate of ATPase 6 and 8, and 1/17 the rate of the average mtDNA gene. The synonymous and replacement substitution rates were used to calculate a new parameter, the "selective constraint ratio". This revealed that even the most variable mtDNA protein was more constrained than the average nDNA protein. Thus, the high substitution mutation rate and strong selective constraints of mammalian mtDNA proteins suggest that mtDNA mutations may result in a disproportionately large number of human hereditary diseases of OXPHOS.

Computer prediction of peptide maps: assignment of polypeptides to human and mouse mitochondrial DNA genes by analysis of two-dimensional-proteolytic digest gels

We have prepared a computer program that predicts complete and partial peptide maps from amino acid sequences. The program fragments amino acid sequences at designated cleavage sites and calculates the molecular weight and relative labeling of each peptide. These data are graphed as log molecular weight of the original protein (X-axis) vs. log molecular weight of the component peptides (Y-axis). The program is interactive, permitting adjustment of a number of graphic parameters and alteration of the position of proteins in the first dimension to accommodate aberrations in protein mobility. The program has been used to predict the V8 protease peptide maps of the 13 open reading frames (ORFs) identified in the human and the mouse mitochondrial DNA (mtDNA) sequences. The results were compared to the V8 protease peptide maps obtained for mouse and human mitochondrially synthesized proteins by two-dimensional proteolytic digest gels. A high correlation was observed between the predicted and observed peptide maps. These results suggest the assignment of several proteins to mtDNA genes.

The use of microcomputers for the quantitation of light intensity patterns using digitized video signals

We have developed an inexpensive yet versatile microcomputer-based system for quantitating light intensity levels in autoradiographs. This system employs a standard video camera interfaced to an analog-to-digital convertor. A program has been written for this system which can measure intensities within a defined region of an autoradiograph, permitting an easy and accurate quantitation of spots or bands of irregular shape.