Biomedical subjects
Publications and source records attributed to E B Arushanian.
After chronic administration of propranolol (1 and 5 mg/kg, 14 days) to rats time-course of forced swimming changed with the decrease of rhythmical index of depression. The drug attenuated depressogenic properties of reserpine and clonidine. Propranolol antidepressive activity is attributed to blockade cerebral adrenoreceptors.
The influence of propranolol on the circadian variations of duration of the anaesthetic effect of diazepam and hexobarbital sodium were studied at 2-hour intervals in two separate round-the-clock observations on mice. Propranolol significantly changed the daily course of the anaesthetic effect of diazepam, caused its inversion and reduced the mean duration of hexobarbital anaesthesia. The observed antagonism between propranolol and hypnotics with varying anaesthetic properties could be attributed to its ability to interfere with both the cerebral neuromediator sleep regulating and beta-adrenoblocking systems but not to its specific blocking effects on pineal functions.
The pineal hormone melatonin in a dose-effect manner (0.1, 1 and 10 mg/kg) reorganized EEG spectral characteristics of rat sensorimotor cortex and hippocampus, decreasing medium (6-12 Hz) and high frequency (12-22 Hz) waves only in the evening. On the contrary, pinealectomy increased high-frequency waves only during morning hours. It is suggested that the observed changes may accompany anxiolytic and hypnotic effects of melatonin.
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Male rats manifested a lesser heart rate variability than the female animals. Optimal shifts of the heart rate mathematical parameters occurred in the dioestrus II and oestrus as compared with other phases of the ovarian cycle. Ovariectomy stabilised the heart activity, the effect being eliminated by administrations of estradiol.
In freely moving cats the behavioral and EEG-shifts, accompanied by myoclonic jerks with slow negative waves and spike-wave complexes in the cortexand caudate nucleus, were recorded following a single intramuscular injection of high penicillin doses. The stimulants of catecholaminergic transmission (L-DOPA and apomorphine) inhibited the development of such phenomena but facilitated origination of tonicoclonic cramps. The inhibitors of catecholaminergic synapses (aminazin and haloperidol) exerted reverse effects. The electrolytic injury to the caudate nucleus head also prevented formation of petit mal-like seizures while the threshold low-frequency stimulation of the nucleus increased penicillin effect.
Two types of behavioral shifts occur in cats after cessation of repeated low-frequency stimulation of the caudate nucleus head. Behavioral depression originates more frequently from the dorsomedial part of the head whereas stimulation of the ventrolateral part induces the activation before depression. The number and pattern of stereotype movements are variously changed against the background of these shifts following administration of the minimal effective phenamine dose. Desorganization takes place after stimulation of the dorso-medial nucleus parts followed by stereotypy reduction or, on the contrary, by its enhancement in combination with caudate activation.
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Gradually accumulating subconvulsive doses of metrazol give rise to behavioral and electrographic effects close to petit mal epilepsy: slow negative waves and spike-wave complexes on EEG, frozen and myoclonic jerks. Intensification of monoaminergic transmission with apomorphine, DOPA or 5-hydroxytryptophan attenuates, but inhibition (chlorpromazine, haloperidol and p-chlorphenylalanine), on the contrary, increases the subconvulsive effect of the metrazol. Low frequency stimulation of the striatum potentiates, and lesion limits expressiveness of metrazol-induced petit mal. Bilateral electrolytic lesion of the striatum eliminates apomorphine, DOPA and haloperidol action, but slight changes the effects of chlorpromazine, 5-hydroxytryptophan and p-chlorphenylalanine.
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. It is suggested that the serotoninergic mechanisms (antagonistic to the dophaminergic system) existing in the ventral part of the caudate nucleus may trigger some caudate functions.
In gradual cumulation of subconvulsive doses of corasole in mice there are certain changes of behaviour and electrographical signs which are close to "petit mal": slow negative waves and peak-wave complexes on the EEG, myoclonic jerks. An increase of monoaminergic transmission of apomorphine, DOPA, or 5--hydroxyhyptophane weakens the preconvulsive effect of corasol, while its inhibition by aminasine, haloperidol and p-chlorphenylalanine on the contrary increases it. A low frequency electric stimulation of the striatum potentiates the expressiveness of corasole "petit mal", while its destruction limits it. A bilateral destruction of the striatum eliminates the action of apomorphine, DOPA and haloperidol but only slightly changes the effect of aminazine, 5-hydroxytryptophane and p-chlorphenylalanine.
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. 5-HTP increased and PCPA decreased the threshold of the arrest reaction induced by low frequency stimulation of ventro-lateral parts of the head of caudate nucleus. 5-HTP and PCPA also influenced in the opposite direction caudate-induced spindle waves in the neocortex. The effects of amphetamine on behavioural and EEG pattern of arrest reaction due to stimulation of the caudate nucleus were antagonized by 5-HTP and potentiated by PCPA. It is supposed that serotonergic mechanisms present in the ventro-lateral regions of the caudate nucleus can modulate stereotyped behaviour triggered by amphetamine.
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. Clozapine also eliminated the weakening of the caudate responses caused by the stereotypical doses of amphetamine.
High-frequency stimulation of the caudate nucleus provoked 2 types of rotatory movements of the head and body in the contra- and ipsilateral direction in unrestricted cats. The contralateral rotations (CR) were provoked from a more extensive area chiefly occupying the dorso-mediocentral portions of the head of the nucleus. In difference from them, the ipsilateral rotations (IR) originated from the ventro-lateral area, possessed tonic component more frequently, were more pronounced and less sensitive to L-DOPA and chlorpromazine. Unilateral damage of the area of CR led to the ipsilateral pose asymmetry. When this asymmetry disappeared administration of L-DOPA or apomorphine readily provoked rotation in the same direction. Destruction of the areas in which the ipsilateral reactions originated gave an opposite result.
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High--frequency stimulation of the caudate nucleus in cats elicits three types of responses: contralateral turning of the head or rotatory psychomotor excitation with contralateral rotation, and ipsilateral turning of the head and body. The latter was obtained mainly from the ventralateral portions of caudate nucleus, while the psychomotor excitation--from the dorsal portions. The rotatory movements are virtually independent of involvement of capsula interna and cortex. Slow synchronized EEG activity occurring at the moment of turning was eliminated by curarization. The caudate rotations are partially triggered by the globus pallidus, as the electrolytic lesion of the latter increases the thresholds of responses although does not completely eliminate them.
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