Evidence for an activating effect of tabernathine on rat brain catechlomine synthesis and elimination

Summary Tabernanthine increased the synthesis and elimination of catecholamines (CA) in the striatum and the rest of the brain, but not in the hypothalamus. These data provide evidence that tabernanthine may activate CA turnover of some brain structures by acting at 2 steps of the metabolic pathway. The results are discussed in relation to a central stimulating action and a hypoxia antagonistic effect of this drug.Acknowledgments. Tabernanthine was generously provided by the Institut de Chimie des Substances Naturelles of the C.N.R.S., Gifsur-Yvette, by B. Poiteau, Dat-Xuong, H. P. Husson, Mme Ch. Kan-Fan and P. Potier.     

In vivo inactivation of denervated corpora allata by precocene II in the bug,Oncopeltus fasciatus

Summary Transection of the nervous connections between the brain and the corpus allatum (CA) inOncopeltus fasciatus does not alter the susceptibility of the CA to precocene II in vivo.The authors wish to thank Patricia Ferugia for rearing the insects; Dr D. Soderlund, Department of Entomology, New York State Agricultural Experiment Station for helpful discussions; and Dr A.O. Lea, Department of Entomology, University of Georgia for technical advice. To whom reprint requests should be addressed     

Immunosuppressive effect of a mouse placenta fraction on H-2 incompatible split heart allografts

Summary A soluble placenta fraction from mice (A.CA) mated with H-2 histoincompatible males (A/Sn) significantly prolonged the survival of heterotopic A/Sn heart transplants in A.CA recipients. No prolongation of A/Sn heart graft survival was obtained with the corresponding A.CA placenta fraction after A.CA × A.CA mating.The work was supported by the Danish Medical Research Council (Project No. 512-3088).     

Genetic functional inactivation of neuronal nitric oxide synthase affects stress-related Fos expression in specific brain regions

To identify neuronal substrates involved in NO/stress interactions we used Fos expression as a marker and examined the pattern of neuronal activation in response to swim stress in nNOS knock-out (nNOS–/–) and wild-type (WT) mice. Forced swimming enhanced Fos expression in WT and nNOS–/– mice in several brain regions, including cortical, limbic and hypothalamic regions. Differences in the Fos response between the two groups were observed in a limited set (6 out of 42) of these brain areas only: nNOS–/– mice displayed increased stressor-induced Fos expression in the medial amygdala, periventricular hypothalamic nucleus, supraoptic nucleus, CA1 field of the hippocampus, dentate gyrus and infralimbic cortex. No differences were observed in regions including the septum, central amygdala, periaqueductal grey and locus coeruleus. During forced swimming, nNOS–/– mice displayed reduced immobility duration, while no differences in general locomotor activity were observed between the groups in the home cage and during the open field test. The findings indicate that deletion of nNOS alters stress-coping ability during forced swimming and leads to an altered pattern of neuronal activation in response to this stressor in specific parts of the limbic system, hypothalamus and the medial prefrontal cortex.Received 29 March 2004; accepted 21 April 2004     

Control of corpus allatum activity inDiploptera punctata: roles of the pars intercerebralis and pars lateralis

Summary Control of the corpora allata (CA) ofDiploptera punctata is maintained by at least 2 factors. The glands are directly inhibited by an allatostatin arriving at the CA via the nervi corporis cardiaci I (NCC I). Destruction of the putative source (median neurosecretory cells, MNC) of the allatostatin by radio-frequency (RF) cautery relieved the inhibition imposed on the CA of virgin females, and the glands became active. Similarly, destruction of the lateral neurosecretory cells (LNC) also relieved the inhibition. We propose that the LNC stimulated the MNC to release allatostatin. RF-cautery did not result in the activation of CA of pregnant or ovariectomized females. Activation of the CA may therefore require not only absence of the inhibitory factor but also the presence of a stimulatory one (perhaps from the ovary).     

基于SHPB试验的高速铁路CRTSⅡ型CA砂浆动态性能

采用分离式霍普金森压杆(Split Hopkinson Pressure Bar,SHPB)试验研究了高速铁路CRTS II型水泥乳化沥青砂浆(CA砂浆)的动态力学性能,并建立了CRTS II型CA砂浆的动态本构关系模型.结果表明:随着应变率的增大,CRTS II型CA砂浆峰值强度逐渐增加,但增加速率随应变率的增大而减小,当应变率从44.17增加至54.79 s-1和从54.79增加至108.47 s-1时,峰值强度分别增加了初始峰值强度的52.28%和7.5%,弹性模量随应变率的变化规律性较差;应变率越大,破坏时的贯通裂纹越多,碎裂程度越大;CRTS II型CA砂浆的比能量吸收随着应变率的增大而增大.所建立的动态本构模型拟合曲线与试验曲线具有较好的一致性.     

Identification of in vitro release products of corpora allata in female and male loreyi leafworms,Leucania loreyi

The in vitro release of juvenile hormones (JH) by female, and of JH acids (JHA) by male corpora allata (CA) ofLeucania loreyi was identified by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Separation and quantification were accomplished by HPLC and GC, respectively. JH II and JH III were the major components released by CA of females. Four JHA analogues were identified as the release products of male CA, i.e. JHA III, Iso-JHA II, JHA II and JHA I. JHA III and Iso-JHA II were reported for the first time as the major release products of CA of adult male Lepidoptera. Iso-JHA II is a new member of the insect juvenile hormone analogue family.     

Effects of constitutively active GTPases on fibroblast behavior

The GTP-binding proteins RhoA, Cdc42 and Rac1 regulate the organization and turnover of the cytoskeleton and cell-matrix adhesions, structures bridging cells to their support, and translating forces, external or generated within the cell. To investigate the specific requirements of Rho GTPases for biomechanical activities of clonal cell populations, we compared side-by-side stable lines of human fibroblasts expressing constitutively active (CA) RhoA, Cdc42 or Rac1. There was no marked effect of any CA GTPase on cell adhesion to different extracellular matrix proteins. Cell spreading was CA Rho GTPase specific and independent of the extracellular matrix proteins allowing adhesion. Mechanical properties were dramatically restricted by CA RhoA on bi- and in tri-dimensional surroundings, were boosted by CA Rac1 on bi-dimensional surroundings only, and were not or marginally affected by CA Cdc42. In conclusion, the action of Rho GTPases appears to depend on the task cells are performing. Received 12 September 2005; received after revision 5 October 2005; accepted 1 November 2005     

Phosphoramidon enhances allatostatin-mediated inhibition of juvenile hormone biosynthesis in the corpora allata of the cockroach, Diploptera punctata.

Use of enkephalinase inhibitor phosphoramidon in the in vitro radiochemical assay for juvenile hormone biosynthesis enhanced allatostatin-mediated inhibition of hormone production by corpora allata of the cockroach, Diploptera punctata. Significant increases in inhibition in day 2 virgin female CA by AST 1 (at 10(-7) M) and AST 4 (10(-8)-10(-7) M) were observed in the presence of phosphoramidon (10(-5) M or greater). No significant increase in inhibition were seen in CA from day 6 mated females with AST 4 (10(-9)-10(-7) M) and phosphoramidon combined. Phosphoramidon alone had no effect on JH biosynthesis. Analysis of allatostatin content of the CA, as determined by ELISA, revealed that addition of phosphoramidon to the medium increased the endogenous allatostatin content in CA of virgin and mated females. The similarity in primary structure between allatostatins and enkephalin-like peptides and their similar distribution makes it probable that phosphoramidon acts by preventing breakdown of allatostatins within the CA.     

Differences in the stimulation by calcium ionophore of juvenile hormone III release from corpora allata of solitarious and gregariousLocusta migratoria

Summary Incubation of the calcium ionophore A23187 resulted in an increase in the median rate of juvenile hormone III release by corpora allata (CA) of both gregarious and solitarious adultLocusta migratoria females at 3, 5 and 8 days after fledging. At all 3 datapoints, the enhancement of release rates was highly significant for CA from gregarious females but not significant for CA from solitarious females.     

Long-term sequelae of perinatal asphyxia in the aging rat

Information on the consequences of perinatal asphyxia (PA) on brain morphology and function in the aging rat is missing although several groups have hypothesized that PA may be responsible for neurological and psychiatric deficits in the adult. We therefore decided to study the effects of PA on the central nervous system (CNS) in terms of morphology, immunohistochemistry, neurology and behavior in the aging animal. Hippocampus and cerebellum were evaluated morphologically by histological, immunohistochemical and magnetic resonance imaging and cerebellum also by stereological tests. Neurological function was tested by an observational test battery and rota rod test. Cognitive functions were examined by multiple-T-maze and the Morris water maze (MWM). Increased serotonin transporter (SERT) immunoreactivity in the CA2 region of the hippocampus and a significant difference in the escape latency, when the platform of the MWM was moved to a new location, were observed in asphyxiated rats. We showed that deteriorated cognitive functions accompanied by aberrant expression of hippocampal SERT and impaired relearning are long-term sequelae of perinatal asphyxia, a finding that may form the basis for understanding CNS pathology in the aging subject, animal or human.     

Juvenile hormone and reproduction in the cricket. II. Effect of rearing temperature on corpus allatum activity (in vitro) in adult females

Summary In the Mediterranean field cricket,Gryllus bimaculatus, reproduction is controlled by temperature and the corpus allatum (CA) hormone JH III. In CA of females reared at 24°12°C(168 h) (high reproduction rate) a first peak in JH III synthesis is reached about 4 days earlier than in those of 20°C females (low reproduction rate). Furthermore, in 20°C animals CA activity is low during the entire oviposition period, whereas at 24°12°C high CA activity is found during this period of adult life. The results indicate a stimulation of CA activity and reproduction by thermoperiods around a constant low temperature.Supported by the DFG (SFB 87 A 4).     

Hormonal control of sexual receptivity in cockroaches

Many animals exhibit specific behaviors associated with sexual receptivity only when they are reproductively competent. In insects with gonadal maturation cycles, these behaviors usually coincide with ovarian matruation. In the cockroachBlattella germanica, juvenile hormone (JH), produced by the corpora allata (CA), regulates female reproductive physiology. Various experimental manipulations, including ablation of the CA, therapy with JH analogs, CA denervation, ovariectomy, and changing nutrient quality, coupled with time-lapse video recording, support the hypothesis that JH also controls female sexual receptivity. A re-examination of the role of the CA in the maturation of male sexual readiness shows that, while sexual behavior develops in the absence of JH in bothB. germanica andSupella longipalpa, JH accelerates the expression of sexual readiness.     

Effects of CA on the epididymis of intact,castrated and TP-treated langurs (Presbytis entellus entellus Dufresne)

Summary Cyproterone acetate (CA) treatment of intact langurs resulted in the disappearance of spermatozoa and regression of epididymal lumen, which can be compared with castration. The antiandrogenic nature of CA was confirmed in castrates treated simultaneously with testosterone propionate.     

CDK5 downregulation enhances synaptic plasticity

CDK5 is a serine/threonine kinase that is involved in the normal function of the adult brain and plays a role in neurotransmission and synaptic plasticity. However, its over-regulation has been associated with Tau hyperphosphorylation and cognitive deficits. Our previous studies have demonstrated that CDK5 targeting using shRNA-miR provides neuroprotection and prevents cognitive deficits. Dendritic spine morphogenesis and forms of long-term synaptic plasticity—such as long-term potentiation (LTP)—have been proposed as essential processes of neuroplasticity. However, whether CDK5 participates in these processes remains controversial and depends on the experimental model. Using wild-type mice that received injections of CDK5 shRNA-miR in CA1 showed an increased LTP and recovered the PPF in deficient LTP of APPswe/PS1Δ9 transgenic mice. On mature hippocampal neurons CDK5, shRNA-miR for 12 days induced increased dendritic protrusion morphogenesis, which was dependent on Rac activity. In addition, silencing of CDK5 increased BDNF expression, temporarily increased phosphorylation of CaMKII, ERK, and CREB; and facilitated calcium signaling in neurites. Together, our data suggest that CDK5 downregulation induces synaptic plasticity in mature neurons involving Ca²⁺ signaling and BDNF/CREB activation.     

Phosphoramidon enhances allatostatin-mediated inhibition of juvenile hormone biosynthesis in the corpora allta of the cockroach,Diploptera punctata

Use of the enkephalinase inhibitor phosphoramidon in the in vitro radiochemical assay for juvenile hormone biosynthesis enhanced allatostatin-mediated inhibition of hormone production by corpora allata of the cockroach,Diploptera punctata. Significant increases in inhibition in day 2 virgin female CA by AST 1 (at 10^–7 M) and AST 4 (10^–8–10^–7 M) were observed in the presence of phosphoramidon (10^–5M or greater). No significant increases in inhibition were seen in CA from day 6 mated females with AST 4 (10^–9–10^–7M) and phosphoramidon combined. Phosphoramidon alone had no effect on JH biosynthesis. Analysis of allatostatin content of the CA, as determined by ELISA, revealed that addition of phosphoramidon to the medium increased the endogenous allatostatin conten in CA of virgin and mated females. The similarity in primary structure between allatostatins and enkephalin-like peptides and their similar distribution makes it probable that phosphoramidon acts by preventing breakdown of allatostatins within the CA.     

早期营养不良对SD大鼠海马AchE和ChAT表达的影响

目的探讨生命早期营养不良对21天雄性sD大鼠中枢AchE和ChAT的影响。方法从妊娠晚期到哺乳期末给予母鼠半量饲料,造成子鼠营养不良,取哺乳期末雄性子鼠脑海马组织进行测量。结果免疫组化结果示：实验组海马CA3区ChAT光密度低于对照组（P〈0．05）,在CA!区无差异（P〉0．05）;而两纽间CAl和CA3区AchE光密度均无差异（P〉0．05）;RT—PCR示：实验组海马ChAT、AchEmRNA少于对照组（P〈0．05）。结论早期营养不良能导致子鼠海马及中枢胆碱能系统发育障碍,可能会影响成年后大鼠学习记忆能力。     

Histochemical localization of carbonic anhydrase in Malpighian tubules ofCulex pipiens

Summary Carbonic anhydrase (CA) activity has been localized histochemically by Hansson's method in Malpighian tubules ofCulex pipiens. The enzyme has been observed on membranes of the cytoplasmic inclusions of Malpighian cells; no CA activity has been found in other cytoplasmic structures. The possible meaning of the localization of the enzyme is discussed.     

The mitigating effect of dietary antioxidants on chemically-induced carcinogenesis

Summary The effect of a dietary antioxidant mixture on 3-methylcholanthrene mediated carcinogenesis in hairless mice was investigated. The antioxidant mixture significantly reduced the frequency of premalignant lesions and their subsequent development into tumors. The similarities in response of chemical and UV light-carcinogenesis to these antioxidants suggest some congruity in the mechanisms of the carcinogenic process.This investigation was supported by National Research Service Award 1 F32 CA05062, awarded by the National Cancer Institute, DHEW and USPH grant CA13464 from the NCI, DHEW. We thank Dr John I. Thornby for statistical analysis of the data.     

A recombinant dromedary antibody fragment (VHH or nanobody) directed against human Duffy antigen receptor for chemokines

Fy blood group antigens are carried by the Duffy antigen receptor for chemokines (DARC), a red cells receptor for Plasmodium vivax broadly implicated in human health and diseases. Recombinant VHHs, or nanobodies, the smallest intact antigen binding fragment derivative from the heavy chain-only antibodies present in camelids, were prepared from a dromedary immunized against DARC N-terminal extracellular domain and selected for DARC binding. A described VHH, CA52, does recognize native DARC on cells. It inhibits P. vivax invasion of erythrocytes and displaces interleukin-8 bound to DARC. The targeted epitope overlaps the well-defined DARC Fy6 epitope. K _D of CA52?CDARC equilibrium is sub-nanomolar, hence ideal to develop diagnostic or therapeutic compounds. Immunocapture by immobilized CA52 yielded highly purified DARC from engineered K562 cells. This first report on a VHH with specificity for a red blood cell protein exemplifies VHHs?? potentialities to target, to purify, and to modulate the function of cellular markers.