Chronic Effects of Modeled Myocardial Infarction, Thoracic Trauma, and Denervation of Hind Limb on Rheographic Parameters of Rat Femoral Arteries In Situ.

In experiments on narcotized male rats (n=85), the mean electroimpedance Z and peak-to-peak magnitudes (the swing ranges) of passive (ΔZp) and active (ΔZa) pulsatile electroimpedance oscillations of isolated segment of femoral arteries were determined in situ. These rheographic parameters (RP) were measured in intact animals and in those with modeled chronic myocardial infarction, chronic denervation of the right hind leg, as well as in rats subjected to sham operations to mimic denervation or infarction (with thoracic trauma). The rats with modeled myocardial infarction demonstrated decreasing trends of all RP. In sham-operated rats with thoracic trauma, ΔZp increased significantly on postsurgery months 2-4 by 4.3 times in comparison with the control. No essential correlation was found in denervated rats between RP of any femoral artery and severity of neuropathic pain syndrome assessed by autotomy of the operated leg. In these rats, the mean electroimpedance Z of any femoral artery was significantly greater than the control level. They demonstrated especially high values of ΔZp with significant difference between ΔZp of innervated and denervated hind leg. In denervated rats, ΔZa was significantly greater than the control value without significant difference between ΔZa of both femoral arteries. The paradoxically great increase of ΔZp (100- and 50-fold for innervated and denervated legs, respectively) and a significant 3-fold increment of ΔZa in both hind legs provoked by denervation of one of them are discussed in relation to searching for the ways of systemic influences on vascular network in clinics and experiments.

Anticonvulsant Effects of Combined Treatment with Citicoline and Valproate on the Model of Acute Generalized Convulsions Induced by Pentylenetetrazole in Wistar Rats.

We studied anticonvulsant effects of combined treatment with citicoline, a nootropic substance with neuroregenerative and neuroprotective activities, and valproate, an antiepileptic agent widely used in the treatment of epilepsy, on the model of pentylenetetrazole-induced (75 mg/kg, intraperitoneally) acute generalized convulsions in male Wistar rats. Combined treatment with citicoline and valproate in minimum effective doses (70 and 300 mg/kg, respectively) potentiated the anticonvulsant properties of both agents.

Аnticonvulsant effects of citicoline and diazepam at their combined application on model of the acute generalized convulsions induced by pentylenetetrazole in Wistar rats.

The purpose: Studying of efficiency of the combined application of the citicoline possessing nootropic and anticonvulsive action and antiepileptic drug of diazepam on the acute generalized convulsions (AGC) caused by a convulsant pentylentetrazole (PTZ). Methods: Experiments are executed on the male Wistar rats (n = 68) weighing 160-190 g on the AGС model caused by of PTZ in a dose of 80 mg/kg, intraperitoneally (i.p.). For studying of efficiency of the combined use of drugs determined the minimum anticonvulsive action of a citicoline (Tserakson, «Nicomed Ferrer Internacional, S.A.¼) and diazepam (Relanium, Warsaw pharmaceutical plant of Polf AO, Warsaw, Poland). For this citicoline were administered i.p. in doses 500 and 300 mg/kg 1 hour before the PTZ and diazepam - in doses of 0,5 and 0,25 mg/kg 30 min before administration of PTZ. Control animals were injected with saline to the same extent and under the same experimental conditions. Results: It is shown that the combined administration of a citicoline and diazepam in minimum active doses (300 and 0.25 mg/kg respectively), increases anticonvulsive properties of both drugs. Conclusion: The combined administration of citicoline with diazepam in minimally active doses enhances anticonvulsant properties of both drugs, thereby reducing the risk of development of side effects. In addition, the research may serve as experimental justification for the use of drugs in case of convulsions for the purpose beneficial effect on cognitive function and delays of progressing of neurodegenerative processes.

[Gaba and its Receptors in Pathogenesis of Epilepsy].

This review presents summarizes data on the structural and functional organization of the GABAergic system of the brain, mechanisms of GABAergic transmission, about the characteristics of GABA-receptors and GABAergic inhibition forms. Reviewed issues of involvement of GABA inhibitory neurotransmitter and various types of GABA-receptors in epileptogenesis. The experimental and clinical data testifying to an important role of GABA and its receptors in an epileptogenesis are presented.

[Autoantibodies to glutamate, GABA and their receptors in epilepsy].

This review discusses the pathogenic role of autoantibodies (autoAB) to excitatory and inhibitory neurotransmitters glutamate, GABA and their receptors in the pathogenesis of epilepsy. The data of clinical and experimental studies show that glutamate AMPA and NMDA- receptors autoAB and GABA receptors autoAB in high titers are highly pathogenic, causing a significant decrease of the density of the receptors and contribute the neuronal death. Discusses the results of experimental data about of the anticonvulsant action of glutamate antibodies (AT) and opposite proconvulsant effect of GABA antibodies in different models of epileptic activity.

Increase of the seizure threshold in C57BL/6 mice after citicoline administration.

We studied the dose-dependent effect of preventive intraperitoneal injection of citicoline (cytidine 5'-diphosphocholine) on acute generalized epileptiform activity in C57Bl/6 mice. The duration of citicoline action was also evaluated. Administration of citicoline in doses of 500 and 1000 mg/kg 1 h before treatment with the convulsant agent pentylenetetrazole produced an anticonvulsant effect. This effect was manifested in an increase of the threshold of clonic seizures and tonic phase of seizures with lethal outcome. Moreover, the latency of seizure development was elevated under these conditions. The anticonvulsant effect of citicoline persisted for 6 h after its injection.

[Effect of citicoline on the development of chronic epileptization of the brain (pentylenetetrazole kindling) and acute seizures reaction of kindled mice C57Bl/6].

In experiments on mice C57Bl/6 was studied effects of citicoline (500 mg/kg, i.p.) on development of chronically epileptization of the brain--pentylenetetrazole (PTZ) kindling (30 mg/kg PTZ, i.p. during 24 days) and on acute generalized seizures (i.v., 1% solution of PTZ with the speed of 0.01 ml/s). It was shown that daily injection of citicoline an hour before the introduction of PTZ had no effect on development of chronically epileptization of the brain --PTZ-kindling (the latency of seizures appearance and their severity). However, citicoIine posses anticonvulsive effects on acute seizures in kindled mice. In animals with increased seizure susceptibility of the brain caused by kindling and severity of seizures 2-3 points injection citicoline after 14 days of kindling had anticonvulsive effect, increasing the threshold clonic seizures. Injection of citicoline during 24 days of kindled animals and severity of seizures 3-5 points caused the increase of thresholds as clonic and tonic phase of seizures with lethal outcome. Thus, the anticonvulsant effect of citicoline more pronounced in the long-term use.

[Neuroimmunological aspects of the pathogenesis of epilepsy].

The review is devoted to the analysis of neuroimmunological aspects of the pathogenesis of epilepsy. Discuss the pathogenetic role of proinflammatory cytokines, antibodies to antigens of the nervous tissue and neurotransmitters, such as dopamine, serotonin, glutamate and GABA in the pathogenesis of epilepsy. The focus of the review is given to clinical research, devoted to the interrelation of the severity of the disease and changes of immunological indices. Disorders of the immune system are most pronounced in drug-resistant forms of epilepsy. Describes the clinical and experimental research, which shows that the use of antiepileptic drugs improves immunity. The use of immunotherapy in combination with anti-epileptics drugs leads to positive results. Thus, the analysis of the immune status of patients with epilepsy can serve as an important criterion for determining the severity of the disease and the appointment of adequate treatment. The authors analyze their own data of anticonvulsant activity of antibodies to glutamate and opposite proconvulsant effect of antibodies to GABA.

Effects of antibodies to glutamate on focal penicillin-induced epileptic activity.

The effects of intranasal pretreatment with antibodies against glutamate on focal penicillin-induced epileptic activity were studied by recording electrocorticogram in non-anesthetized freely moving male Wistar rats. Anticonvulsant effects of intranasal administration of anti-glutamate antibodies (300 µg/kg) 1 h before application of penicillin (30,000 U/ml) on the sensorimotor cortex was demonstrated: the latency of ictal discharges increased and their frequency decreased.

Elevation of seizure threshold after intranasal administration of anti-glutamate antibodies to C57BL/6 mice.

The dose-dependent effect of intranasal administration of antibodies to glutamate on acute generalized epileptic activity was studied in C57Bl/6 mice. It was shown that pretreatment with antibodies in doses of 100, 300, and 500 µg/kg 1 h before titration with convulsant pentylenetetrazole had anticonvulsant effects. This treatment was followed by an increase in the thresholds of clonic and tonic seizures with fatal outcome and lengthening of seizure latency. The most pronounced effect was observed in doses of 300 and 500 µg/kg. Comparison of the anticonvulsant effect of antibodies in active immunization with glutamate-BSA conjugate and systemic intraperitoneal administration of purified anti-glutamate antibodies revealed advantages of intranasal administration.

[Direct involvement of the glucose and Mg(2+)-ATP in the regulation of the GABAA-coupled Cl-,H(CO3(-) -activated Mg(2+)-ATPase of the plasma membrane from rat brain in vitro experiences].

Effect of the glucose and Mg(2+)-ATP on the coupled with CABA(A)-receptor Cl-,HCO3(-)-activated Mg(2+)-ATPase of the plasma membranes from rat brain involving from "basal" Mg(2+)-ATPase which it is activated by Cl-,HCO3(-) ions it was investigated. The glucose (1-10 mM) decreased the "basal" Mg(2+)-ATPase activity on 17% and completely eliminated the enzyme activation by 10 mM Cl(-)+2 mM HCO3(-) ions. The variety effect of the glucose and Mg(2+)-ATP on the activation of the '"basal" Mg(2+)-ATPase by variety concentrations of anions it was established. So it was found that in the presence Mg(2+)-ATP in the incubation medium > 1 mM the enzyme activation by 10 mM Cl- + 2 mM HCO ions not appear. However, in the presence of the glucose (10 mM) the inhibiting effect of the Mg(2+)-ATP on the enzyme is disappears and Cl-,HCO3(-)-ATPase activity is restored. While, in the presence of the high concentrations 40 mM Cl- + 8 mM HCO3(-) in the incubation medium the inhibiting effect of the glucose and Mg(2+)-ATP it was negligible (-20%). It was conclusion about direct involvement of the glucose and Mg(2+)-ATP in the regulation of the coupled with CABA(A)-receptor Cl-,HCO3(-)-ATPase activity of the neuronal membrane under different concentration anions in the incubation medium.

Effect of HCO3(-) ions on the ATP-dependent GABA(A) receptor-coupled Cl(-) channel in rat brain plasma membranes.

We studied the effect of Cl(-) (10-75 mM) and HCO(3)(-) ions (10-25 mM) on the ATP-dependent GABA(A) receptor-coupled Cl(-) channel (Cl(-)-ATPase) in rat brain plasma membranes. The total enzyme activity was detected in the presence of both anions at a Cl(-)/ HCO(3)(-) ratio of 5:1 (Cl(-), HCO(3)(-)-ATPase). Specific inhibitors of P-type transport ATPases (N-ethylmaleimide, o-vanadate, and oligomycin) suppressed Cl(-), HCO(3)(-)-ATPase, while the Cl(-)- and HCO(3)(-)-ATPase activities were low sensitive to these ligands. Bicuculline abolished the activating effect of Cl(-) and HCO(3)(-) ions on the enzyme. HCO(3)(-) ions had no effect on the ATP-dependent Cl(-) transport into proteoliposomes (with the involvement of reconstituted ATPase). In experiment with Cl(-)-preloaded liposomes, addition of HCO(3)(-) ions to the incubation medium caused the reversion of Cl(-) transport (ion efflux from liposomes). Our results suggest that HCO(3)(-) ions play an important role in the modification of properties of the ATP-dependent GABA(A) receptor-coupled Cl(-) channel and GABA(A) receptor-induced Cl(-)/ HCO(3)(-) exchange. These ions are probably involved in GABA(A) receptor-induced Cl(-)/ HCO(3)(-) exchange in neuronal membranes.

[Influence of antibodies to the glutamate on convulsive reaction to mice C57Bl/6 in term of chronic epileptogenesis].

It was shown that the preliminary single i.p. injection of antibodies (AB) to glutamate (GLU) 1,5 hours prior to the first injection pentylenetetrazole (prior to the beginning of kindling) did not have an effect on latency period of appearance and the severity of convulsive reactions in the mice of C57Bl/6. The administrations of AB to GLU at the different stages of kindling animals with different severity of seizures did not have an effect on their severity. Thus, AB to GLU did not posses antiepileptic effect. However, AB to GLU posses anticonvulsive action on the acute seizures reaction, inducing an increase in the thresholds of clonic seizures and tonic phase seizures with lethal outcome as well as an extended latency period of occurrance these seizures in mice with enhanced kindling-producing convulsive readiness of the brain. This effect was revealed at the different stages of kindling in animals with the severity of seizures 2-3 and 4-5 marks. Possible to assume, that the mechanisms of chronic epileptogenesis (in this case, in the form kindling-dependent enhanced convulsive readiness of the brain) and those of the acute convulsive reaction are not similar.

[Autoantibodies to glutamate, GABA, dopamine and serotonin in the dynamics of development of chronic brain epileptization in mice C578l/6].

In experiments on mice C57Bl/6 was studied the possibility of production of glutamate, GABA, dopamine and serotonin autoantibodies in the dynamics of development of chronic brain epileptization--pharmacological kindling, induced by daily administration of pentylenetetrazol in subconvulsive dose (30 mg/kg) during 24 days. 14 days after the start of the kindling autoantibodies to glutamate was detected in all experimental animals, to CABA--in 60% of mice, to serotonine--in 70%, and to dopamine--in 90%. After 24 days--the number of animals with autoantibodies to glutamate and dopamine was decreased, to serotonin--increased, and to GABA--was not altered. It was shown the relationship between detection neurotransmitters autoantibodies and severity of the convulsive reaction.

[Effects of systemic administration of glutamate antibodies on acute convulsive reaction of C57B1/6 mice].

The impact of a single intraperitoneal injection of antibodies to glutamate (AG) on acute generalized epileptic activity provoked by systemic introduction of pentilentetrasol was studied in C57B1/6 mice. It was found that AG in doses 10, 25 and 50 mg/kg 1.5 and 24 hours after AG injection produced an anti-epileptic action by raising thresholds of clonic convultions and tonic phase of convultions with lethal outcome and by extending a latent period of their appearance. Later (30 hours after antibodies introduction in a dose 25 mg/kg) AG had no effects on the convulsive reaction thresholds, 48 hours after AG injection they produced a proepileptic effect by lowering the threshold of a clonic convulsion phase.

Cl- conduction of GABA(A)-receptor complex of synaptic membranes of rat brain cortex after development of chronic epileptization of the brain (pharmacological kindling).

Experiments on Wistar rats showed that basal and muscimol-induced 36Cl- entry into synaptoneurosomes isolated from the brain cortex decreased after kindling (30 mg/kg pentylenetetrazole intraperitoneally for 30 days) in animals with seizure severity score 4-5. Changes in Cl- conduction during kindling are discussed.

Effect of classic convulsants on Cl- conductance of the GABA(A) receptor complex in membranes of cerebral cortex cells at the early stage of kindling.

Muscimol-stimulated Cl- conductance of synaptoneurosomes from the cerebral cortex of Wistar rats increased during the early stage of pharmacological kindling not inducing the seizure response in animals. Picrotoxin, bicuculline, and pentylenetetrazole potentiated inhibition of muscimol-dependent 36Cl- entry into synaptoneurosomes, which attested to increased sensitivity of the GABA(A) receptor/Cl- ionophore complex to classic convulsants.

Cl(-) conduction of GABAA receptor complex of synaptic membranes in the cortex of rats at the middle stage of chronic cerebral epileptization (pharmacological kindling).

Experiments on Wistar rats showed a decrease in basal and muscimol-stimulated 36Cl(-) entry into synaptoneurosomes isolated from the cerebral cortex during the middle stage of kindling (30 mg/kg pentylenetetrazole intraperitoneally for 14 days) characterized by the development of convulsions of higher (2 points) severity in comparison with the previous stage.

Immunobiological specificity of antibodies against glutamate and gamma-aminobutyric acid.

Experiments on C57Bl/6 mice showed that chronic epileptization of the brain (pharmacological pentylenetetrazole kindling) is accompanied by induction of autoantibodies against glutamate and GABA. Immunohistochemical similarity of antibodies against glutamate and GABA was demonstrated. Study on the model of pentylenetetrazole-induced acute generalized epileptiform activity showed high immunobiological specificity of intraperitoneally injected antibodies against GABA and glutamate: antiepileptic effect of antiglutamate antibodies and proepileptic effect of antibodies against GABA.

Effect of systemic treatment with antibodies against glutamate on the seizure response of C57Bl/6 mice after pentylenetetrazole kindling.

We studied the effect of single intraperitoneal injection of antibodies against glutamate on acute generalized epileptiform activity induced by intravenous injection of pentylenetetrazole in kindled C57Bl/6 mice. We found that in animals at various stages of kindling, administration of antibodies against glutamate in a dose of 25 mg/kg 1.5 h before testing increases the threshold of clonic seizures and tonic phase of seizures with lethal outcome and latency of seizure development, i.e. produces an antiepileptic effect.