BACKGROUND: Neurosteroids are investigated as effective antidotes for the poisoning induced by tetramethylenedisulfotetramine (TMDT) as well as treatments for epileptic spasms during infancy. Both these conditions are quite resistant to pharmacotherapy; thus, a search for new treatments is warranted. METHODS: In this study, we determined the efficacy of two novel neurosteroids, pregnanolone glutamate (PAG) and pregnanolone pyroglutamate (PPG), and tested these drugs in doses of 1-10 mg/kg (ip) against the TMDT syndrome and in our rodent model of infantile spasms. RESULTS: Only PPG in doses 5 and 10 mg/kg suppressed the severity of the TMDT syndrome and TMDT-induced lethality, while the 1 mg/kg dose was without an effect. Interestingly, the 1 mg/kg dose of PPG in combination with 1 mg/kg of diazepam was also effective against TMDT poisoning. Neither PAG nor PPG were effective against experimental spasms in the N-methyl-D-aspartate (NMDA)-triggered model of infantile spasms. CONCLUSIONS: While evidence suggests that PAG can act through multiple actions which include allosteric inhibition of NMDA-induced and glycine receptor-evoked currents as well as augmentation of ɣ-aminobutyric acid subtype A (GABAA) receptor-induced currents, the agent appears to neither have the appropriate mechanistic signature for activity in the infantile spasm model, nor the adequate potency, relative to PPG, for ameliorating the TMDT syndrome. The full mechanisms of action of PPG, which may become a potent TMDT antidote either alone or in combination with diazepam are yet unknown and thus require further investigation.

• MeSH
• diazepam farmakologie   MeSH
• hlodavci MeSH
• křeče u dětí * chemicky indukované   farmakoterapie   MeSH
• kyselina glutamová MeSH
• kyselina pyrrolidonkarboxylová MeSH
• N-methylaspartát toxicita   terapeutické užití   MeSH
• neurosteroidy * MeSH
• neurotoxické syndromy * MeSH
• pregnanolon škodlivé účinky   MeSH
• spasmus MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Psychosis is a state of altered thoughts which often accompanies schizophrenia. It was suggested that changes in energetic metabolism accompany psychosis and post-psychosis states. Here, we use the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 to experimentally induce psychosis-like behavior in rats. We addressed an effect of single and repeated (5×) MK-801 application (0.3 mg/kg; i.p.) on the energy metabolism in homogenates and crude mitochondrial fraction (CMF) of the striatum (STR), prefrontal cortex (PFC), and the hippocampus (HIP) of the adult male Wistar rat (n = 39). In each brain region, we assessed activity of glycolytic (hexokinase (HK) and lactate dehydrogenase (LDH)) and Krebs cycle enzymes (citrate synthase (CS) and malate dehydrogenase (MDH)) 2 h and 3 days (3d) after the last MK-801 application together with relative respiratory rates assessment in tissue homogenate. In STR, a single MK-801 application led to a decrease in the LDH (p = 0.0035) and the increase of the MDH (p = 0.0043) activities following 3d. Therein, repeated MK-801 doses evoked increased LDH (p = 0.0204) and CS (p = 0.0019) activities in the homogenate 2 h and increased HK (p = 0.0007) 3d after the last application. Elevated HK activity within CMF was observed after 3d (p = 0.0054). In PFC, repeated MK-801 application decreased HK activity in the homogenate 3d after the final application (p = 0.0234). Correspondingly, PFC HK activity in CMF of repeated administration samples dropped (p = 0.003). In HIP, repeated MK-801 administration led to increased respiration of SDH (p = 0.0475) only 2 h after the last application and decreased CS activity (p = 0.0160) was observed 3d after the last application. Our results indicate a progressive metabolic dysregulation of glycolytic and Krebs cycle enzymes following repeated inhibition of NMDA receptors activity in a region-specific manner. Energetic alterations may form a basis for persisting cognitive problems during and following a psychosis in schizophrenia patients.

• MeSH
• citrátový cyklus MeSH
• citrátsynthasa metabolismus   farmakologie   MeSH
• dizocilpinmaleát * farmakologie   MeSH
• hexokinasa metabolismus   farmakologie   MeSH
• hipokampus MeSH
• krysa rodu rattus MeSH
• L-laktátdehydrogenasa metabolismus   MeSH
• lidé MeSH
• N-methylaspartát * farmakologie   MeSH
• potkani Wistar MeSH
• prefrontální mozková kůra MeSH
• receptory N-methyl-D-aspartátu metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In spite of use of cannabidiol (CBD), a non-psychoactive cannabinoid, in pediatric patients with epilepsy, preclinical studies on its effects in immature animals are very limited. In the present study we investigated anti-seizure activity of CBD (10 and 60 mg/kg administered intraperitoneally) in two models of chemically induced seizures in infantile (12-days old) rats. Seizures were induced either with pentylenetetrazol (PTZ) or N-methyl-D-aspartate (NMDA). In parallel, brain and plasma levels of CBD and possible motor adverse effects were assessed in the righting reflex and the bar holding tests. CBD was ineffective against NMDA-induced seizures, but in a dose 60 mg/kg abolished the tonic phase of PTZ-induced generalized seizures. Plasma and brain levels of CBD were determined up to 24 h after administration. Peak CBD levels in the brain (996 ± 128 and 5689 ± 150 ng/g after the 10- and 60-mg/kg doses, respectively) were reached 1-2 h after administration and were still detectable 24 h later (120 ± 12 and 904 ± 63 ng/g, respectively). None of the doses negatively affected motor performance within 1 h after administration, but CBD in both doses blocked improvement in the bar holding test with repeated exposure to this task. Taken together, anti-seizure activity of CBD in infantile animals is dose and model dependent, and at therapeutic doses CBD does not cause motor impairment. The potential risk of CBD for motor learning seen in repeated motor tests has to be further examined.

• MeSH
• antikonvulziva farmakologie   MeSH
• epilepsie farmakoterapie   MeSH
• kanabidiol farmakokinetika   farmakologie   MeSH
• krysa rodu rattus MeSH
• modely nemocí na zvířatech MeSH
• mozek účinky léků   MeSH
• N-methylaspartát farmakologie   MeSH
• pentylentetrazol farmakologie   MeSH
• potkani Wistar MeSH
• záchvaty farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Suprachiasmatic nucleus (SCN) of the hypothalamus is the master clock that drives circadian rhythms in physiology and behavior and adjusts their timing to external cues. Neurotransmitter glutamate and glutamatergic receptors sensitive to N-methyl-d-aspartate (NMDA) play a dual role in the SCN by coupling astrocytic and neuronal single cell oscillators and by resetting their phase in response to light. Recent reports suggested that signaling by endogenous cannabinoids (ECs) participates in both of these functions. We have previously shown that ECs, such as 2-arachidonoylglycerol (2-AG), act via CB1 receptors to affect the SCN response to light-mimicking NMDA stimulus in a time-dependent manner. We hypothesized that this ability is linked to the circadian regulation of EC signaling. We demonstrate that circadian clock in the rat SCN regulates expression of 2-AG transport, synthesis and degradation enzymes as well as its receptors. Inhibition of the major 2-AG synthesis enzyme, diacylglycerol lipase, enhanced the phase delay and lowered the amplitude of explanted SCN rhythm in response to NMDAR activation. Using microscopic PER2 bioluminescence imaging, we visualized how individual single cell oscillators in different parts of the SCN respond to the DAGL inhibition/NMDAR activation and shape response of the whole pacemaker. Additionally, we present strong evidence that the zero amplitude behavior of the SCN in response to single NMDA stimulus in the middle of subjective night is the result of a loss of rhythm in individual SCN cells. The paper provides new insights into the modulatory role of endocannabinoid signaling during the light entrainment of the SCN.

• MeSH
• agonisté excitačních aminokyselin farmakologie   MeSH
• cirkadiánní rytmus účinky léků   fyziologie   MeSH
• endokanabinoidy fyziologie   MeSH
• krysa rodu rattus MeSH
• lipoproteinlipasa antagonisté a inhibitory   metabolismus   MeSH
• myši transgenní MeSH
• myši MeSH
• N-methylaspartát farmakologie   MeSH
• nucleus suprachiasmaticus cytologie   účinky léků   fyziologie   MeSH
• potkani Wistar MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Neuroactive steroid 20-oxo-5β-pregnan-3α-yl L-glutamyl 1-ester (PA-Glu), a synthetic analogue of naturally occurring 20-oxo-5β-pregnan-3α-yl sulfate (pregnanolone sulfate, PA-S), inhibits N-methyl-D-aspartate (NMDA) receptors and possesses neuroprotective properties and minimal adverse effects. Herein, we report in vivo effects of new structural modifications of the PA-S molecule: a nonpolar modification of the steroid D-ring (5β-androstan-3α-yl L-glutamyl 1-ester, AND-Glu), attachment of a positively charged group to C3 (20-oxo-5β-pregnan-3α-yl L-argininate dihydrochloride salt, PA-Arg) and their combination (5β-androstan-3α-yl L-argininate dihydrochloride salt, AND-Arg). The first aim of this study was to determine the structure-activity relationship for neuroprotective effects in a model of excitotoxic hippocampal damage in rats, based on its behavioral correlate in Carousel maze. The second aim was to explore side effects of neuroprotective steroids on motor functions, anxiety (elevated plus maze) and locomotor activity (open field) and the effect of their high doses in mice. The neuroprotective properties of PA-Glu and AND-Glu were proven, with the effect of the latter appearing to be more pronounced. In contrast, neuroprotective efficacy failed when positively charged molecules (PA-Arg, AND-Arg) were used. AND-Glu and PA-Glu at the neuroprotective dose (1 mg/kg) did not unfavorably influence motor functions of intact mice. Moreover, anxiolytic effects of AND-Glu and PA-Glu were ascertained. These findings corroborate the value of research of steroidal inhibitors of NMDA receptors as potential neuroprotectants with slight anxiolytic effect and devoid of behavioral adverse effects. Taken together, the results suggest the benefit of the nonpolar D-ring modification, but not of the attachment of a positively charged group to C3.

• MeSH
• agonisté excitačních aminokyselin toxicita   MeSH
• antagonisté excitačních aminokyselin chemická syntéza   farmakologie   MeSH
• bludiště - učení účinky léků   MeSH
• chování zvířat účinky léků   MeSH
• hipokampus účinky léků   metabolismus   patologie   patofyziologie   MeSH
• lokomoce účinky léků   MeSH
• molekulární struktura MeSH
• myši MeSH
• N-methylaspartát toxicita   MeSH
• neuroprotektivní látky chemická syntéza   farmakologie   MeSH
• pohybová aktivita účinky léků   MeSH
• potkani Long-Evans MeSH
• pregnanolon analogy a deriváty   chemická syntéza   farmakologie   MeSH
• receptory N-methyl-D-aspartátu antagonisté a inhibitory   metabolismus   MeSH
• sírany chemická syntéza   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

N-Methyl-D-aspartátový (NMDA) receptor patří do skupiny glutamátových receptorů, které se dále dělí na ionotropní a metabotropní. V CNS má vliv na synaptickou plasticitu a rozvoj neuronálních synapsí. Ionotropní NMDA receptory jsou aktivovány glutamátem, díky čemuž proudí pozitivně nabité ionty skrz membránu po svém koncentračním gradientu. Nicméně nadměrné hladiny glutamátu působí excitotoxicky díky vysokým intracelulárním hladinám Ca2+ a mohou vést k buněčné smrti neuronů pozorované např. u neurodegenerativních onemocnění. Antagonisté NMDA receptorů, mezi které patří například dizocilpin, ovlivňují prostupnost NMDA receptoru a zamezují tak vstupu iontů Ca2+ do buňky. Dizocilpin působí jako nekompetitivní antagonista NMDA receptoru, má antikonvulzivní a anestetické účinky. Jeho terapeutické použití u lidí není vhodné z důvodu výskytu četných vedlejších účinků, experimentálně je však využíván jako farmakologicky indukovaný animální model schizofrenie.

N-Methyl-D-aspartate (NMDA) receptor belongs to the group of glutamate receptors, which are further divided into ionotropic and metabotropic. It affects synaptic plasticity and the development of neuronal synapsis in CNS. Ionotropic NMDA receptors are activated by glutamate, thereby flowing positively charged ions through the membrane along its concentration gradient. However, glutamate overload leads to excitotoxicity, due to high levels of Ca2+, which leads to cell death assocciated with neurodegenerative diseases. NMDA antagonists like dizocilpine reduce intracellular concentration of Ca2+ by modulating permeability of NMDA receptor channel. Dizocilpine act as a non-competitive NMDA receptor antagonist with anticonvulsant and anesthetic properties. Its therapeutic use in humans is limited due its numerous side effects, but it is experimentally used as an animal model of schizophrenia.

• MeSH
• agonisté excitačních aminokyselin terapeutické užití   MeSH
• antipsychotika terapeutické užití   MeSH
• dizocilpinmaleát * terapeutické užití   MeSH
• farmakologické jevy MeSH
• krysa rodu rattus MeSH
• modely u zvířat MeSH
• morčata MeSH
• N-methylaspartát terapeutické užití   MeSH
• schizofrenie farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• morčata MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy MeSH

A broad variety of central nervous system diseases have been associated with glutamate induced excitotoxicity under pathological conditions. The neuroprotective effects of neurosteroids can combat this excitotoxicity. Herein, we have demonstrated the neuroprotective effect of novel steroidal N-methyl-D-aspartate receptor inhibitors against glutamate- or NMDA- induced excitotoxicity. Pretreatment with neurosteroids significantly reduced acute L-glutamic acid or NMDA excitotoxicity mediated by Ca2+ entry and consequent ROS (reactive oxygen species) release and caspase-3 activation. Compounds 6 (IC50 = 5.8 μM), 7 (IC50 = 12.2 μM), 9 (IC50 = 7.8 μM), 13 (IC50 = 1.1 μM) and 16 (IC50 = 8.2 μM) attenuated glutamate-induced Ca2+ entry more effectively than memantine (IC50 = 18.9 μM). Moreover, compound 13 shows comparable effect with MK-801 (IC50 = 1.2 μM) and also afforded significant protection without any adverse effect upon prolonged exposure. This drop in Ca2+ level resulted in corresponding ROS suppression and prevented glutamate-induced caspase-3 activation. Therefore, compound 13 has great potential for development into a therapeutic agent for improving glutamate-related nervous system diseases.

• MeSH
• kultivované buňky MeSH
• kyselina glutamová škodlivé účinky   MeSH
• N-methylaspartát škodlivé účinky   MeSH
• neurony cytologie   účinky léků   metabolismus   MeSH
• neuroprotekce účinky léků   MeSH
• neuroprotektivní látky chemie   farmakologie   MeSH
• neurotransmiterové látky chemie   farmakologie   MeSH
• potkani Wistar MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• receptory N-methyl-D-aspartátu antagonisté a inhibitory   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Excessive stimulation of NMDA receptors with glutamate or other potent agonists such as NMDA leads to excitotoxicity and neural injury. In this study, we aimed to provide insight into an animal model of brain excitotoxic damage; single unilateral infusion of NMDA at mild dose into the hippocampal formation. NMDA infusion induced chronic, focal neurodegeneration in the proximity of the injection site. The lesion was accompanied by severe and progressive neuroinflammation and affected preferentially principal neurons while sparing GABAergic interneurons. Furthermore, the unilateral lesion did not cause significant impairment of spatial learning abilities. Finally, GluN1 and GluN2B subunits of NMDA receptor were significantly upregulated up to 3 days after the NMDA infusion, while GABAA α5 subunit was downregulated at 30 days after the lesion. Taken together, a single infusion of NMDA into the hippocampal formation represents an animal model of excitotoxicity-induced chronic neurodegeneration of principal neurons accompanied by severe neuroinflammation and subunit specific changes in NMDA and GABAA receptors.

• MeSH
• bludiště - učení účinky léků   fyziologie   MeSH
• degenerace nervu diagnostické zobrazování   metabolismus   patologie   MeSH
• funkční lateralita MeSH
• hipokampus diagnostické zobrazování   účinky léků   metabolismus   patologie   MeSH
• modely nemocí na zvířatech MeSH
• N-methylaspartát aplikace a dávkování   toxicita   MeSH
• neurodegenerativní nemoci diagnostické zobrazování   metabolismus   patologie   MeSH
• neuroimunomodulace fyziologie   MeSH
• neurony účinky léků   metabolismus   patologie   MeSH
• potkani Long-Evans MeSH
• receptory GABA-A metabolismus   MeSH
• receptory N-methyl-D-aspartátu metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

NMDA receptors (NMDARs) comprise a subclass of neurotransmitter receptors whose surface expression is regulated at multiple levels, including processing in the endoplasmic reticulum (ER), intracellular trafficking via the Golgi apparatus, internalization, recycling, and degradation. With respect to early processing, NMDARs are regulated by the availability of GluN subunits within the ER, the presence of ER retention and export signals, and posttranslational modifications, including phosphorylation and palmitoylation. However, the role of N-glycosylation, one of the most common posttranslational modifications, in regulating NMDAR processing has not been studied in detail. Using biochemistry, confocal and electron microscopy, and electrophysiology in conjunction with a lentivirus-based molecular replacement strategy, we found that NMDARs are released from the ER only when two asparagine residues in the GluN1 subunit (Asn-203 and Asn-368) are N-glycosylated. Although the GluN2A and GluN2B subunits are also N-glycosylated, their N-glycosylation sites do not appear to be essential for surface delivery of NMDARs. Furthermore, we found that removing N-glycans from native NMDARs altered the receptor affinity for glutamate. Our results suggest a novel mechanism by which neurons ensure that postsynaptic membranes contain sufficient numbers of functional NMDARs.

• MeSH
• Cercopithecus aethiops MeSH
• COS buňky MeSH
• endoplazmatické retikulum metabolismus   MeSH
• glykosylace MeSH
• Golgiho aparát metabolismus   MeSH
• HEK293 buňky MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• N-methylaspartát chemie   metabolismus   MeSH
• nervový přenos * MeSH
• neurony chemie   metabolismus   MeSH
• polysacharidy metabolismus   MeSH
• receptory N-methyl-D-aspartátu chemie   metabolismus   MeSH
• synapse metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Požívanie alkoholu je celosvetovo rozšírený fenomén, ktorého dopad na ľudský organizmus môže byť fatálny. Dôsledky alkoholizmu sú nielen zdravotné ale aj sociálne a ekonomické. Podstata vzniku závislosti na alkohole ostáva naďalej neúplne objasnená. Predložený článok je venovaný objasneniu mechanizmov pôsobenia alkoholu na centrálny nervový systém na molekulárnej úrovni a jeho interakciám s neurotransmitermi.

Alcohol consumption is a worldwide spread phenomenon influence of which on a human organism may even be fatal. Consequences of alcoholism are not only medical but also social and economical. The basic principles of alcohol dependence development remain still unclear. Submitted article offers a short review of alcohol's effects mechanisms and it's interaction with neurotransmitters.

• Klíčová slova
• alkohol, fluidita biomembrán, neurotransmitery,
• MeSH
• agonisté dopaminu škodlivé účinky   MeSH
• ethanol * aplikace a dávkování   farmakologie   škodlivé účinky   MeSH
• lidé MeSH
• membránové lipidy chemie   metabolismus   MeSH
• membrány * fyziologie   MeSH
• N-methylaspartát antagonisté a inhibitory   metabolismus   MeSH
• nervový přenos fyziologie   účinky léků   MeSH
• neurotransmiterové látky * farmakologie   metabolismus   MeSH
• pití alkoholu * škodlivé účinky   MeSH
• receptory GABA účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH