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A L Kotova S A Kondratskaya I M Yasutis 《Journal of hygiene, epidemiology, microbiology, and immunology》1988,32(1):71-78
Salmonella carrier state (42.6%-S. enteritidis and 34.4%-S. dublin) was demonstrated in subjects after acute salmonellosis as well as in healthy persons infected with salmonella as a result of occupational exposure to poultry (8.8% in humans exposed to chickens and 6.1% in those exposed to ducks) and sheep (2.8%). The carrier state was accompanied by intermittent pain in the epigastrium, diminished appetite, diarrhoea etc. Most of the carrier subjects with a history of salmonellosis exhibited, upon rectoromanoscopy, a varying degree of proctosigmoiditsi. The etiological role of S. typhimurium was proved beyond doubt, as well as its ability to cause salmonellosis outbursts, sporadic cases of the disease and the carrier state. When large industrial facilities specializing in poultry processing were investigated, the salmonella carrier state was revealed in practically healthy poultry--in 16% of chickens and 12% of ducks. The salmonella organisms isolated from carrier persons had, with some exceptions, typical properties, being virulent in that they caused death of experimental animals, seeded their internal organs and induced pathogenicity-associated enzymes. Multiple resistance to antibiotics was demonstrated in salmonella isolated from poultry; also determined was its plasmid nature. Pronounced resistance of the above salmonella subtypes to tetracycline-related antibiotics and streptomycin may be due to the fact that these drugs are used in poultry raising. 相似文献
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Inhibition of hippocampal LTP by ginkgolide B is mediated by its blocking action on PAF rather than glycine receptors 总被引:6,自引:0,他引:6
Kondratskaya EL Pankratov YV Lalo UV Chatterjee SS Krishtal OA 《Neurochemistry international》2004,44(3):171-177
Platelet-activating factor (PAF), a biologically active lipid (1-O-alkyl-2-acetyl-sn-glycero-3-phosphoholine), is identified in different regions of brain, including hippocampus. Specific PAF-activated receptors (PAFRs) are expressed in corresponding brain areas. PAF has been proposed to be a retrograde messenger of long-term potentiation (LTP): the antagonist of PAFRs, ginkgolide B (or BN52021) prevents induction of LTP. Recently it has been found that ginkgolide B is also an efficient blocker of the glycine receptor (GlyR) operated chloride channels (IC(50)=270+/-10 nM in hippocampal pyramidal neurons). The question is as follows: is the alteration of LTP by BN52021 due to the PAF antagonism or to the inhibition of glycine-gated chloride channels? We have studied the effects of ginkgolides B and J on LTP induced in the CA1 area of rat hippocampus. Ginkgolide J which is the weakest blocker of PAFR (IC(50)=54 microM, as compared to IC(50)=2.5 microM for ginkgolide B) inhibits GlyR-operated channels with IC(50)=2.0 microM. This assures a convenient concentration window which allows to inhibit GlyR-operated channels without affecting PAFRs. An amount of 5 microM of ginkgolide J did not prevent the induction of LTP, while ginkgolide B (5 microM) completely inhibited this phenomenon. The effect of ginkgolide B on LTP did not alter considerably if GlyRs were blocked by strychnine (2 microM). Strychnine itself had no significant effect on the induction of LTP. Both ginkgolides and strychnine significantly facilitated short-term potentiation (STP). Our data support a hypothesis according to which ginkgolides affect LTP by inhibiting PAFRs. 相似文献
3.
ATP is considered to impact on fast synaptic transmission in several regions of the CNS, including the CA1 and CA3 areas of the hippocampus. The existing paradigm suggests that ATP induces synaptic responses in CA3 pyramidal cells, and a fast ATP-mediated component is observed in cultured hippocampal slices mainly under conditions of
a synchronous discharge from multiple presynaptic inputs. We confirmed the existence of a fast ATP-mediated component within
electrically evoked EPSCs (eEPSCs) in CA3 neurons of acute slices of the rat hippocampus using a whole-cell patch-clamp recording mode. In approximately 50% of the
examined cells, eEPSCs were not completely inhibited by co-applied glutamate receptor antagonists, NBQX (50 μM) and D-APV
(25 μM). The residual current was sensitive to ionotropic P2X receptor antagonists, such as suramin (25 μM) and NF023 (2 μM).
Known purinergic receptor modulators, ivermectin (10 μM) and PPADS (10 μM), practically did not affect EPSCs, whereas a nonhydrolyzable
ATP analog, ATPγS (100 μM), slightly decreased the EPSC amplitude. Moreover, ATPγS (100 μM) at a holding potential of −70
mV generated a slow inward current in most recorded neurons, which was insensitive to glutamate receptor antagonists. This
fact is indicative of the ionotropic P2X receptor activation.
Neirofiziologiya/Neurophysiology, Vol. 40, No. 1, pp. 21–29, January–February, 2008. 相似文献
4.
Active compounds of Ginkgo biloba extract (ginkgolides A, B, C, and J) were tested on the main ligand-operated conductances in rat neurons using a patch-clamp technique in the whole-cell configuration and a concentration-clamp technique. It was found that all ginkgolides reduced glycine-activated currents in concentration- and use-dependent manners, whereas they did not affect other tested ligand-gated receptors (NMDA- and GABA-activated ones). The IC50 values calculated from dose-response curves were as follows: 1.97, 0.273, 0.267, and 2.0 M for ginkgolides A, B, C, and J, respectively (200 M Gly ).The Hill coefficient in all cases was close to 1.0, which indicates a single site of the drug binding to the glycine-activated receptor. 相似文献
5.
BN52021, a platelet activating factor antagonist, is a selective blocker of glycine-gated chloride channel 总被引:5,自引:0,他引:5
Kondratskaya EL Lishko PV Chatterjee SS Krishtal OA 《Neurochemistry international》2002,40(7):647-653
We have found that the platelet activating factor antagonist (BN52021) is an effective blocker of the glycine (Gly) receptor-mediated responses in the hippocampal pyramidal neurons of rat. Using the whole-cell voltage clamp and concentration clamp recording techniques, we investigated the mechanism underlying the inhibitory action of this terpenoid on the glycine-induced chloride current. BN52021 selectively and reversibly inhibits glycine current in a non-competitive and voltage-dependent fashion. The antagonistic effect of this substance is more pronounced at positive membrane potentials. At holding potential −70 mV and in the presence of 200 μM glycine IC50 value for the blocking action of BN52021 was 270±10 nM. Repetitive applications of BN52021 reveal the use-dependence of its blocking action. When co-applied with strychnine (STR), a competitive glycine receptor antagonist, BN52021 does not alter the IC50 value for strychnine. The inhibitory effect of BN52021 on gamma-aminobutyric acid (GABA) current is at least 25 times less potent than the effect on glycine current. This substance fails to affect AMPA and NMDA responses. It may be concluded that BN52021 inhibits glycine-gated Cl− channels by interacting with the pore region and does not compete for the strychnine-binding centre. 相似文献
6.
Ievglevskyi O Palygin O Kondratskaya E Grebenyuk S Krishtal O 《Purinergic signalling》2012,8(4):705-713
Cannabinoids exert powerful action on various forms of synaptic plasticity. These retrograde messengers modulate GABA and glutamate release from presynaptic terminals by acting on presynaptic CB1 receptors. In particular, they inhibit long-term potentiation (LTP) elicited by electrical stimulation of excitatory pathways in rat hippocampus. Recently, LTP of the field excitatory postsynaptic potential (fEPSP) induced by exogenous ATP has been thoroughly explored. The present study demonstrates that cannabinoids inhibit ATP-induced LTP in hippocampal slices of rat. Administration of 10 μM of ATP led to strong inhibition of fEPSPs in CA1/CA3 hippocampal synapses. Within 40 min after ATP removal from bath solution, robust LTP was observed (fEPSP amplitude comprised 130.1 ± 3.8% of control, n = 10). This LTP never appeared when ATP was applied in addition to cannabinoid receptor agonist WIN55,212-2 (100 nM). Selective CB1 receptor antagonist, AM251 (500 nM), completely abolished this effect of WIN55,212-2. Our data indicate that like canonical LTP elicited by electrical stimulation, ATP-induced LTP is under control of CB1 receptors.
Electronic supplementary material
The online version of this article (doi:10.1007/s11302-012-9296-5) contains supplementary material, which is available to authorized users. 相似文献7.
K. Nonaka E. Kondratskaya M. Maeda T. Yamaga N. Murayama M. C. Shin N. Akaike 《Neurophysiology》2009,41(4):250-257
The action of ginkgolide B (GB), a powerful compound of Ginkgo biloba extract, on glycine-mediated spontaneous currents in rat spinal sacral dorsal commissural nucleus (SDCN) neurons was examined.
IPSCs evoked in spinal cord slices were inhibited in a dose-dependent manner by the addition of GB to the superfusion solution.
The amplitude of eIPSCs was reduced to 61 ± 6.4% by 10 μM GB with acceleration of the kinetics of the currents, indicating
the effect of GB on channel pores. Both the amplitude and success ratio (Rsuc) of eIPSC induced by electrical focal stimulation of single glycinergic nerve endings (boutons) also changed in the presence
of 1 μM GB. These data suggest that GB modulates not only post-synaptic glycine receptors but also the pre-synaptic glycine
release machinery. 相似文献
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