[Analysis of functional and biochemical changes in feline cerebral hemispheres after subchronic haloperidol administration].

Feline experiments have revealed that subchronic haloperidol causes asymmetric changes in the mesencephalic levels of dopamine and serotonin and impairs intrahemispheric balance between the dopaminergic and serotoninergic systems. At the same time the neuroleptic increases motor asymmetry, which appears in response to apomorphine, and changes the nature of interhemispheric relationships. The findings suggest that these changes may be one of the causes of extrapyramidal disorders associated with long-term use of the neuroleptic.

[The behavioral and neurochemical changes in rats caused by the subchronic administration of haloperidol].

Rat experiments showed that subchronic haloperidol enhanced or perverted motor asymmetry appearing in response to apomorphine, resulted in imbalance between the dopaminergic and serotoninergic systems and increased norepinephrine levels. It was concluded that intra- and interhemispheric imbalance might be one of the causes of extrapyramidal disorders associated with the long-term administration of the neuroleptic.

[Behavioral and EEG signs of the convulsive action of kynurenine and quinolinic acid in cats].

Administration of quinolinic acid but not L-kynurenine into the cat caudate nucleus was found to produce the appearance of epileptiform charges in the EEG with concomitant behavioral convulsions. A combination of quinolinic acid injections with systemic administration of penicillin resulted in the development of the status of myoclonic convulsions alternating with generalized tonicoclonic seizures. These states were eliminated by diazepam.

[Pharmacological analysis of the anticonvulsant action of kavinton].

In experiments on rats it was found that cavinton administered in doses of 1-30 mg/kg exerted a distinct dose-dependent anticonvulsant effect, according to the test of maximal electroshock, not less than that of phenobarbital, difenin and carbamazepine. Combined use of cavinton and these drugs potentiated its anticonvulsant action. The involvement of noradrenergic systems, in particular, alpha 1-adrenoceptors, in the anticonvulsant effect of cavinton is suggested.

[Complex approach to evaluating the antipsychotic properties of neuroleptics modeled on fenamine sterotypy in cats].

It was shown that the ability of neuroleptics to cause the high-amplitude wave bursts in sensorimotor cortex in cats with phenamine stereotypy may indicate antipsychotic properties of the drugs whereas suppression of motor automatism largely testifies to their extrapyramidal effects.

[Changes in cat behavior as affected by intracerebral microinjections of kynurenine and quinolinic acid].

Behavioural changes induced by microinjections of neuroactive tryptophan metabolites: L-kynurenine sulfate (KYN, 50-1,000 micrograms) and quinolinic acid (QA, 20-1,000 micrograms) were studied in chronic experiments on cats with cannulas implanted into nuclei caudati. Unlike KYN, whose effects were scarce and nonspecific, QA (500 and 1,000 micrograms) produced marked motor and emotional shifts. The effects were manifested in contralateral rotatory movements, limb hyperkinesis, emotional strain, malice, fear, aggression with snarling and hissing, attack on provocation.

[Effect of Cavinton on convulsions caused by chemical substances].

Cavinton was shown to protect mice against convulsions induced by corazol, strychnine and thiosemicarbazide. In addition, cavinton exhibited a definite antagonism to convulsive reactions produced by systemic administration of penicillin to cats and a combined administration of penicillin (intramuscularly) with tryptophan metabolite, quinolinic acid (intracerebroventricularly). The anticonvulsant action of cavinton is suggested to be due to the involvement of the brain GABA- and serotonergic mechanisms.

[Dissociation between movement disorders and EEG shifts in amphetamine-induced stereotypy in the cat].

In experiments on cats it is established that between the degree of EEG desynchronization in the sensorimotor cortex and expressiveness of the stereotype movements, a dissociation is possible which is most distinctly revealed in comparative studies of haloperidol, clozapine and metoclopramide--neuroleptics with different correlation of antipsychotic and extra-pyramidal properties. Local destruction of the ventral parts of the caudate nucleus head enhances motor disturbances resulting from amphetamine administration, but weakens its effect on the cortex. Elimination of the dorsal parts produces an opposite effect.

[Use of cavinton in epilepsy].

The authors studied the effect of cavinton (15-45 mg/day) and its combinations with different anticonvulsants on the time-course of different forms of epilepsy. In 20 of the 31 patients studied treatment with cavinton either significantly decreased the frequency of attacks or led to their complete disappearance; in 7 patients the improvement was insignificant and in 4 the condition deteriorated. The greatest effect of cavinton was observed in generalized tonic-clonic convulsions and when they were combined with absences.

[Characteristics of the effect of haloperidol and clozapine on the rhythmic features of phenamine sterotypy in cats].

Experiments on cats with the use of an electromechanical rotameter enabling one to separately record head turns to the right and to the left were made to examine the action of the neuroleptics on the time-course of changes in the horizontal component of amphetamine stereotypy. It was shown that haloperidol which destabilizes the oscillatory curve of the rate of head turns led to a progressive decrease in the number of movements. Clazapine also destabilized the rhythmic process.

[Fenamin stereotypy as a stable rhythmic process].

In cats with amphetamine stereotypy, the rate of horizontal head movements ranges rhythmically in time. Marked stereotypy is in agreement with more regular and low amplitude waves on the total activity curve. During amphetamine effect abatement, the curve gets stabilized as regards the amplitude and period.

[Dynamics of interhemispheric asymmetry in fenamine stereotypy in the cat].

Stereotyped behaviour induced by d,1-amphetamine in cats is a stable rhythmical process. Expressed stereotypy is characterized by stabilization of the summate curve of motor activity fluctuations by amplitude and periods with different asynchronous changes in the number of the left and right head turnings. Low-frequency stimulation of the caudate nucleus and administration of neuroleptics (haloperidol and clozapine) facilitate destabilization of the fluctuations curve and synchronize changes in the frequency of the left and the right head turnings.

[Different role of various regions of the caudate nucleus in phenamine-induced stereotyped behavior in cats].

Electrolytic ablation of the ventral parts of the cat caudate nucleus head results in an increase of frequency and disorganization of the pattern of the stereotype head turnings, induced by large doses of amphetamine. Lesion of the dorsal parts, on the other hand, is attended with a decreased number and limited manifestation of stereotype movements. A similar effect appears following a low frequency electrical stimulation of the nucleus ventral part.

[Effect of phenamine and haloperidol on stereotyped behavior in response to electric stimulation of the substantia nigra in cats].

On being given in low doses (0.25 mg/kg) amphetamine potentiates stereotyped behavior induced in cats by stimulation of substantia nigra. As the dose is raised the effect increases eventuating in the formation of the typical amphetamine-induced stereotypy.

[Effect of stimulation and destruction of the substantia nigra on phenamine- and apomorphine-induced stereotypy in cats].

Electrical stimulation of substantia nigra enhances the behavioral and electroencephalographic parameters of the stereotypy induced by threshold doses of amphetamine (0.5 and 1 mg/kg) but does not produce any effect on apomorphine action (2 and 5 mg/kg). Bilateral electrolytic destruction of the brain structure, on the contrary, reduces the action of amphetamine, especially in the early postoperative period.

[Possible discrepancy between behavioral adequacy and motor automatisms in cats with phenamine-induced stereotypy].

Experiments in cats were made to study the effect of the increasing doses of the neuroleptics haloperidol and clozapin as well as those of metoclopramide with weak antipsychotic properties on various characteristics of amphetamine-induced stereotypy. Haloperidol was shown to return the animals' behavior adequacy to normal and to concurrently eliminate the motor automatisms. Clozapin produced an earlier recovery of the psychoemotional state, exerting a less powerful effect of motor manifestation of stereotypy.

[Stereotypical behavior developing after electric stimulation of the substantia nigra in cats].

A weak unilateral electrical stimulation of pars compacta of substantia nigra in cats provokes a stereotype behaviour, by its pattern resembling stereotypy induced by amphetamine. During poststimulatory stereotypy, there is a weakening of the arrest reaction induced by low-frequency stimulation of the caudate nucleus. Low doses of haloperidol which do not disturb the spontaneous behaviour, readily weaken trace nigral stereotypy.

[Neurophysiologic and pharmacologic evidence of autoregulationin the nigrostriatal system].

Repeated electrical stimulation of substantia nigra in cats produces a progressive relaxation of the poststimulation stereotyped behavior. This effect may be consequent on the development of autoinhibition in the nigro-striatal pathways since the rate of stereotypy inhibition increases in the presence of low doses of amphetamine and apomorphine but is reduced by little doses of haloperidol. A possible reason for autoinhibition is likely to involve an activation of the presynaptic dopaminergic receptors on nigro-striatal axons.

[Influence of GABA-ergic substances on the effects of caudate nucleus stimulation and fenamin stereotyping in cats].

Arrest reaction, circling, cortical spindles induced by electrical stimulation of the caudate nucleus and stereotypy behaviour provoked by threshold doses of amphetamine were recorded in chronic experiments on cats. Sodium hydroxybutyrate and phenibut facilitated motor arrest, while qammalon did not exhibit such an effect. All the substances markedly decreased thresholds of cortical caudate-induced spindles.

[Effect of large doses of phenamine after previous administration of 5-hydroxytryptophan and para-chlorophenylalanine on the spontaneous behavior of cats and the effects induced by caudate nucleus stimulation].

In non-immobilized male cats the stereotypy behavior evoked by threshold doses of phenamine was registered cyclographically along with the motion arrest reaction, circular reaction and their electrographic "adjuncts" (cortical caudate-induced spindles and desynchronization). Against the background of 5-Hydroxytryptophan (5-HT), a serotonine precursor, and p-chlorphenylalanine (PCPA), an inhibitor of the mediator synthesis, phenamine produced stereotype in the formerly administered dose, but its picture changed. Under the effect of 5-HT the amplitude of the stereotypy movements declined, they would become better organized, whereas after administration of PCPA they would, on the contrary, assume a chaotic "unshackled" character.

[Effect of clozapine on the behavioral and electrographic indices of the arrest function of the caudate nucleus in cats].

In unrestrained cats clozapine in increasing doses (1--5 mg/kg) caused a behavioural depression and suppression of amphetamine-induced stereotypy of behaviour against the background of marked vegetative shifts. Similarly to chlorpromazine clozapine intensified the behavioural arrest reaction) and electrographic (neocortical caudate spindle) indices of the arrest function of the caudate nucleus. Arrest reaction changed more distinctly in stimulation of the ventral parts of the head of the nucleus.

[Effect of para-chlorophenylalanine and 5-hydroxytryptophan on the caudate nucleus in cats].

In unrestrained cats parachlorophenylalanine, an inhibitor of serotonin synthesis, increased the thresholds of the contraversive reaction and arrest reaction accompanied by spindle-waves in the sensory-motor cortex in the stimulation of the rostro-ventral areas of the caudate nucleus. The reactions evoked from the dorso-medial areas of the head and the body of the nucleus changed differently. On the contrary, 5-hydroxytryptophane, serotonin precursor, increased most of the indices of the caudate activity independently of the site of stimulation.

The role of serotonergic mechanisms on amphetamine-induced stereotyped behaviour.

The effects of 5-hydroxytryptophan (5-HTP) and p-chlorophenylalanine (PCPA) on amphetamine-induced stereotyped behaviour (ASB) and on the behavioural and EEG effects of caudate nucleus stimulation have been studied in the cat. After a pretreatment with 5-HTP (10--30 mg/kg) the threshold dose of amphetamine to induce ASB remained the same, but its pattern assumed a more organized character with reduced amplitude of stereotyped movements. On the contrary, after PCPA (200 mg/kg) a disorganized pattern of ASB was observed.

[Effect of corazole on the functional activity of the caudate nucleus].

In chronic experiments with freely moving cats the action of diverse metrazol doses on the d,1-amphetamine-induced stereotype behaviour and the arrest reaction following low frequency stimulation of the caudate nucleus was studied. After injections of metrazol (20--30 mg/kg, i.c.