Biomedical subjects

A A Shandra

Publications and source records attributed to A A Shandra.

At least 37 records · Page 2Linked to original sources

PubMed1992

[The effect of activation of the superior colliculus on the convulsive activity during picrotoxin-induced kindling].

Bilateral administration of picrotoxin, bicucullin or benzilpenicillin to the colliculi superior induced high-amplitude hypersynchronous discharges in rats. In these conditions, a suppression of generalized seizures induced with picrotoxin, was observed. The superior colliculi seem to play a significant part in antiepileptic system, the part being realized through generator mechanism.

Animals↗

PubMed1992

[Effects of neurotropin on seizure activity in picrotoxin kindling].

It is shown that both intracerebral and intraperitoneal neurotropin administration resulted in a decrease of seizure susceptibility of preliminary picrotoxin--kindled rats. On the other hand, neurotropin did not change the course of kindling development. Under conditions of acute picrotoxin--induced seizures it was observed that preliminary cycloheximide (protein-synthesis blocker) administration abolished anticonvulsant properties of neurotropin. It is concluded that anticonvulsant effects of neurotropin are realized via modulation of endogenous peptides synthesis and, in particular, cerulein.

Animals↗

PubMed1991

[The role of the opiate mechanisms of the hippocampus and substantia nigra in the behavioral and convulsive disorders in picrotoxin-induced kindling].

It was shown in the experiments on rats that the repeated picrotoxin administration resulted in the kindling of generalized seizures. Generalized convulsions were followed by the development of either postictal depression or explosiveness. The injection of mu-opiate agonist met-enkephalin into hippocampus of kindled rats resulted in the increase in the severity of seizure reactions which were induced by picrotoxin and also in the increase in the number of animals with postictal explosiveness. The injection of dynorphin-A-1-13 (kappa-opiate agonist) into substantia nigra reticulata induced the locomotor depression which was like one in postictal period and resulted in the decrease of picrotoxin-induced seizures severity. It was concluded that mu-opiate system of hippocampus took part in the formation of generator of pathologically enhanced excitation in the structure during kindling and the development of seizure syndrome, providing also the postictal explosiveness. Kappa-opiate system of substantia nigra plays an important role in the activation of the antiepileptic system, limitation of seizures and the development of postictal depression.

Analgesics↗

PubMed1991

[The role of the adrenoreactive structures of the amygdaloid complex in regulating blood coagulation].

In chronic experiments on male cats the irritation of adrenoreactive amygdalar structures by catecholamines injection through chemotrode was performed. It was shown that these structures took part in the regulation of the blood coagulative system and specificities of alpha- and beta-adrenoreactive structures influences upon different phases of blood coagulation were also discovered.

Adrenergic alpha-Antagonists↗

PubMed1991

Influence of cerebro-spinal fluid of picrotoxin kindled rats on seizure susceptibility and locomotor activity of recipients.

Repeated picrotoxin administration (ip) in subthreshold doses in rats resulted in kindling of generalized seizures. Decrease of locomotor activity in kindled rats occurred in interictal periods. Intra-cerebroventricular microinjection to intact recipients of cerebrospinal fluid (CSF) of kindled but not intact rats or those after acute picrotoxin-induced convulsions, induced a decrease of locomotor activity and severity of acute picrotoxin induced seizures. These effects of CSF were blocked by naloxone pretreatment and were absent after injection of CSF to which protease inhibitors were not added. It is concluded that the release of endogenous opioid peptide substance(s) takes place in CSF of kindled animals which cause the interictal decrease of locomotor activity and may play the role of endogenous anticonvulsive factors controlling epileptic activity induction.

Animals↗

PubMed1991

[Effects of activation and lesions of the superior colliculi of the lamina quadrigemina on epileptic activity in rats].

In acute experiments on rats it was shown that activation of SC by bilateral microinjection of penicillin (5-15 IU) or bicuculline (25-50 ng) resulted in the increased latency and decreased severity of i.p. picrotoxin-induced seizures (2 mg/kg). The suppression of behavioral convulsions and the decreased epileptic activity in the hippocampus and cerebral cortex were followed by occurrence of spike discharges in SC with an amplitude of 200-500 mcV and frequency of 5-12/sec which testifies to the formation of penicillin- or bicuculline-induced generator excitation in SC. The lesions of SC by kainic acid administration resulted in the decreased seizure threshold and, also, facilitated the development of seizure under conditions of picrotoxin kindling. The conclusion is made that SC activation plays an important role in the realization of functional integrative activity of the antiepileptic system.

Animals↗

PubMed1991

[Anticonvulsive effects of neurotropin].

The antiepileptic action of neurotropin (Nippon Zoki Pharmaceutied Co. Ltd., Japan) was investigated in acute experiments on rats, mice and cats. The increasing of latent period of the first seizures which were picrotoxin-induced and enhancing of this type of seizures were observed correspondently in 1-24 hours and 8-9 days after intraventricular neurotropin injection. Intraperitoneal neurotropin injection (0.2-0.5 ml) to mice caused dosage-dependent antiseizure action on the model of generalized picrotoxin-induced seizures. +Anticonvulsant++ effect of neurotropin was observed during five days. The intraventricular neurotropin injection to cats led to strychnine (0.1%) induced cortical foci suppression.

Animals↗

PubMed1990

[The formation of motor programs during pharmacological kindling].

In Wistar rats with the kindling phenomenon, the number of animals with three or more not stimulus-directed forms of swimming was increased. Obvious changes of swimming behaviour in these animals were also observed after intrastriatal injections of carbachol, apomorphine, haloperidol, muscimol and picrotoxin. These findings are discussed from the standpoint of a latent generator of pathologically enhanced excitation in the striatum which changed the ability of these rats to develop behavioral programs.

Animals↗

PubMed1990

[The role of the substantia nigra in the anticonvulsive and antiaggressive effects of diazepam during pharmacological kindling].

The seizure activity was investigated on the model of pharmacological kindling which was induced by repeated picrotoxin injections in the subthreshold dose, after the tryptic fragment of T5 protein-human diazepam binding inhibitor (DBI) (10 micrograms) injection into a reticular part of substantia nigra. An increase in the seizure reaction and suppression of the antiseizure diazepam action were observed. Intranigral DBI injection induced no change in a threshold of "attacks" in rats which were induced through electric shocks delivered to animals with an electrode floor and no changes in antiaggressive diazepam action were observed under such conditions.

Aggression↗

PubMed1990

[Effects of extracts of different parts of the brain of kindled animals on seizure activity of recipient rats].

The peptide-containing fraction was emitted from the hippocampal and ventral mesencephalic region tissue of rats kindled with subconvulsant doses of corazol. Extracts were prepared by the help of hot acetic acid on the stage of generalized clonic-tonic seizure development. The intraventricular injection of VMR-extracts in relatively high dose increased seizure reactions which were induced in intact recipient rats by intraperitoneal corazol injection. The intraventricular injection of the extract in relatively low dose (100 times less) suppressed corazol-induced seizures in recipients. Data are discussed from the point of view of pathological epileptic system formation and the role played by peptides in supporting it's activity during pharmacological kindling.

Animals↗

PubMed1990

[Modeling of torsion dystonia through electric stimulation of the vermis cerebellum cortex].

It was shown in acute experiments on cats that electrical stimulation (ES) (100-300 Hz, 5.0-10.0 V) of cat's cerebellar vermal cortex (lobules V and VI) was followed by head deviation in the direction opposite to that side on which the animal was laying, posture and movement disturbances and also by simultaneously occurred contraction of musculus-antagonists of extremities. The tonic and posture disturbances were observed during 40-60 s after ES cessation. During this time in the zone of ES in cerebellar cortex the high-amplitude synchronized activity was registered which was due to generator of pathologically enhanced excitation (GPEE) formation. Intraperitoneal diazepam (0.5-1.0 mg/kg, 30 min before the observation) pretreatment suppressed GPEE formation that correlated with suppression of syndrome manifestations. The conclusion was made that cerebellar hyperactive cortex, which was due to GPEE induction, might have played the role of pathological hyperactive determinant structure of the described syndrome.

Animals↗

PubMed1990

[Appearance of parkinsonian syndrome after administration of delta sleep-inducing peptide into the rat substantia nigra].

Bilateral microinjection of delta-sleep-inducing peptide (DSIP) (10.0 nmol) into the substantia nigra provoked hypokinesia and rigidity in rats observed during 4.0 hours. Injection of DSIP in dose of 5.0 nmol into the substantia nigra or into the nuclei caudati in dose of 10.0 nmol did not induce such symptoms. The enhanced slow-wave activity was recorded in caudate nuclei during hypokinesia and rigidity which demonstrated the formation of the generator of pathologically enhanced excitation (GPEE). The systemically cyclodol administration resulted in abolishment of rigidity and increase in locomotor activity. The conclusion is that bilateral intranigral DSIP injection caused acute parkinson syndrome in rats due to the formation of cholinergic GPEE in caudate nuclei. The hyperactive caudate nuclei act as the pathologic determinant which induces the parkinson syndrome.

Acute Disease↗

PubMed1990

Antiepileptic effects of cerebellar nucleus dentatus electrical stimulation under different conditions of brain epileptisation.

It was shown in acute experiments on cats that high frequency (100-300 Hz) electrical stimulation of dentate nucleus led to the solitary epileptic foci of relatively weak intensity suppression and at the same time caused the activation of stronger focal epileptic activity. Electrical stimulation of nucleus dentatus suppressed the epileptic activity of grand mal type and increased seizures in rats with petit mal form of epileptogenesis which was formed in rats during pentylenetatiozol kindling. It was concluded that there is a relation between the antiepileptic effects of nucleus dentatus irritation and intensity as well as the form of epileptic activity induced experimentally.

Animals↗

PubMed1990

[Effects of destruction and activation of limbic structures on formation of convulsive and emotional disorders during picrotoxin kindling].

In the experiments on rats it was shown that the picrotoxin kindling, which consists of the progressive increasing of convulsive reactions during daily systemic administration of picrotoxin in subconvulsive dosages results also in the development of the pathologically enhanced defensive reactions. The destruction of hippocampal structures by kainic acid prevented the seizure syndrome, while their activation due to blood injection in hippocampus promoted its development; under these conditions the kindling of pathologically enhanced defensive reactions was not significantly changed. Bilateral amygdalar destruction significantly attenuated the development of pathologically increased defensive behavior; under these conditions the seizure syndrome was not significantly changed. The data are discussed on the theory of generator, and systemic mechanisms of neuropathologic syndromes and show that picrotoxin kindling results in the formation of two different pathologic systems which cause the development of two mentioned syndromes: seizure syndrome and syndrome of pathologically enhanced defensive behavior.

Amygdala↗

PubMed1989

[Effect of delta sleep-inducing peptide, anticonvulsant preparations and nicotinamide on generalized seizure activity].

The influence of delta-sleep inducing peptide (DSIP) upon seizures induced by corazol, bicuculline, picrotoxin, strychnine, thiosemicarbazide were investigated in experiments on F1(CBA X C57 BL/6) mice. It was shown that DSIP increased the latency of first seizure manifestation which were induced by corazol, bicuculline and picrotoxin and also resulted in a suppression of seizure severity of corazol and bicuculline induced seizures. Anticonvulsant action of DSIP was evident under the condition of the mild severity seizures development. The effect of DSIP was mostly pronounced in range of its doses from 10 to 100 mcg/kg. DSIP when combined with phenobarbital, carbamazepine, diphenylhydantoin or nicotinamide enhanced the antiepileptic effects of these anticonvulsant drugs.

Animals↗

PubMed1989

[Effect of brain extracts from rats subjected to korazol kindling on generalized epileptic activity].

The pharmacological kindling was induced in rats by corazol repeated injections in subthreshold doses. The peptide-containing fraction was emitted from animal brains by the help of hot acetic acid on the stage of generalized clonic-tonic seizures development. Intraperitoneal injection of brain extracts of kindled rats significantly increased corazol and picrotoxin induced seizure severity in mice. The effect was removed by preliminary injection of naloxone or by preventive incubation of extracts with pronase. Intraventricular injection of extracts to intact rats increased the seizure severity which was provoked by corazol and in high doses induced in rats generalized seizure reactions.

Animals↗

PubMed1989

[Development of motor and emotional disorders in rats during daily administration of subliminal doses of picrotoxin].

It was shown in the experiments on rats, that three neuropathological syndromes develop as a result of daily subthreshold picrotoxin injections (1.25 mg/kg). Maximal expression of syndromes was different during various periods of kindling. The development of seizure syndrome was followed by prevalence of enhanced electrical activity in hippocampus; the development of "akinetic" syndrome was the same in the caudate nuclei. Data are discussed on the positions of theory of the generator, determinant and systemic mechanisms of neuropathological syndromes.

Animals↗

PubMed1988

[Anticonvulsant properties of the cerebrospinal fluid during activation of the antiepileptic system of the brain].

Cerebrospinal fluid (CSF) was obtained after 30-40 sessions of daily electrical stimulation of the cat cerebellum vermis. The intraventricular injection of CSF (10 microliters) to Wistar rats increased the latent period of initial seizure manifestations, significantly reduced the number of animals with seizures and reduced the severity of seizures induced by korazol injection (40 mg/kg). Analogous seizure changes were observed in rats after intraventricular injection of CSF (10 microliters) from cats subject to 3-10 electroshock seizure fits. Intraventricular injection of CSF (250 microliters) obtained from cats after electroshock to cats with strychnine-induced epileptic foci in the brain cortex led to the suppression of the epileptic activity. The conclusion was made that different ways of antiepileptic system activation cause the accumulation of endogenous antiepileptic substances in CSF.

Animals↗