[Learning of rats predisposed to catalepsy in Morris water test].

It was shown that GC rats predisposed to catalepsy do not differ from Wistar rats in success rate or latency (time of finding of the hidden escape platform) in the Morris water test. However, unlike Wistar, GC rats are inclined to passive drift and longer floating episodes. Rats of the MD+ strain predisposed to hyperkinesis in the form of horizontal pendulum-like movements of the head and upper limb girdle show longer latency and lower rate of successful trials than Wistar or MD-, rats selected for absence of the pendulum-like movements.

[Catalepsy and "nervousness" in rats: results of replicated selection].

Replicated breeding during five generations from an outbred population of Wistar rats performed, in contrast to the previous breeding, differentially for predisposition to catalepsy and "nervousness" confirmed earlier data that catalepsy and "nervousness" are two phenotypic expressions of the same bipolar catatonic genotype.

[Some neuroendocrinological changes in rats of cataleptic strain GC. Influences of ontogenesis and generation of breeding].

The content of biogenic amines: dopamine, noradrenaline and serotonine, in rats of cataleptic strain GC as compared with the control strain Wistar at the age of 1 and 5 months is decreased, the maximal decrease being found in the so-called "nervous" animals. The aldosterone content was decreased at 5 month age in the GC rats. The testosterone content at the age of 1 month in GC rats does not differ from that in Wistar rats, but at the age of 5 months it was decreased as compared to Wistar, the maximal decrease being found again in "nervous" GC rats.

Effects of experimental increases and decreases in thyroxine levels on the extent of cataleptic freezing reactions in rats.

Numerous clinical observations have provided evidence for a tight connection between impairments in the functions of the hypothalamo-hypophyseal-thyroid system and nervous and mental disorders. The aim of the present work was to compare the effects of experimental decreases and increases in blood thyroxine levels on the extents of two types of pathological freezing reaction in male Wistar rats--spontaneous catalepsy and catalepsy evoked by pinches at the nape of the neck (pinch-induced catalepsy). Chronic administration of the thyroxine synthesis inhibitor propylthiouracil (5 mg/kg/day for 28 days) significantly decreased the blood hormone level and sharply increased the proportion of animals showing spontaneous catalepsy and the immobility time, but had no effect on the extent of pinch-induced catalepsy.

[Dual manifestation of catatonic reaction in rats].

Results of genetic, neurophysiological, neurochemical and pharmacological suggest that the cataleptic freezing and "nervousness" observed in the cataleptic rat strain GC have a common mechanism. There seems to be a physiological factor causing catalepsy, upon reaching a certain level of intensity, to be transformed into "nervousness", which is observed both at different period and/or moment of individual life and in the processes of breeding the strain for predisposition to catalepsy.

Chronic administration of imipramine decreases freezing time in rats genetically predisposed to catalepsy.

The effects of acute and chronic imipramine treatment on the degree of catalepsy were compared in GC rats genetically predisposed to catalepsy. We recorded the time over which the rats remained in a vertical position they were placed. As differentiated from acute treatment, chronic administration of imipramine dose-dependently decreased the time of freezing in GC rats.

[Catatonia or depression: the GC rat strain as an animal model of psychopathology].

The utility of "incomplete" genetic animal models of human diseases, in particular, psychoses, is discussed. The GC rat strain selected for predisposition to cataleptic reactions is described. It is shown that in many of their characteristics, GC rats are similar to schizophrenic and depressive patients.

Correlation between cataleptic freezing and prepulse inhibition of the startle reflex in rats.

GC rats, bred for a predisposition to cataleptic freezing, were found to show a significant negative correlation between the duration of freezing and the level of prepulse inhibition of the startle reflex. In addition, a group of GC rats characterized by increased "nervousness" also showed a negative correlation between the duration of freezing and the extent of habituation of the startle reflex. These correlations were not seen in Wistar rats.

[Effect of experimental elevation and decrease of thyroxine level on catalepsy in rats].

Thyroid dysfunction is associated with mental disorders. The present study was aimed to reveal the effects of experimental decrease and increase of thyroxine level on expression of two types of extensive freezing: spontaneous and pinch-induced catalepsy, in Wistar rat males. Chronic administration of thyroxine synthesis inhibitor, propylthiouracil (5 mg/kg/day, 28 days), markedly decreased plasma hormone level and at the same time produced a significant increase in percentage of spontaneously cataleptic animals and immobility time, but had no effect on the expression of pinch-induced catalepsy.

[Bipolar manifestation of cataleptic reactions in rats].

Selection of GC rats for the predisposition to cataleptic freezing has increased not only the frequency, intensity, and duration of freezing, but also the proportion of irritable or "nervous" rats with enhanced anxiety, defensive behavior with vocalization, jerky running, and jumpiness. An increased amplitude of the startle reflex is a correlate of this "nervousness." The results of the comparison of some behavioral characters in the nervous and freezing GC rats, as well as in F1 and F2 offspring from homogeneous crosses between nervous and freezing GC rats suggest that cataleptic freezing and nervousness are two poles of the same bipolar catatonic reaction.

[Correlation between cataleptic freezing and prestimulation inhibition of the startle reflex in rats].

In rats of GC strain bred for predisdposition to cataleptic freezing, a significant negative correlation between the duration of freezing and the level of prepulse inhibition (PPI) of the startle reflex, has been found. Besides, in a group of GC rats specific by their "nervousness" and jumpiness, there was also a negative correlation between the duration of freezing and the habituation to the startle reflex. None of this correlation have been found in Wistar rats.

Effect of chronic administration of imipramine on 2A-serotonin receptor mRNA in brain cortex of rats predisposed and resistant to catalepsy.

Rats selected by predisposition to catalepsy showed decreased level of 2A-serotonin receptor mRNA in the frontal cortex in comparison with Wistar rats (p<0.05). Chronic administration of tricyclic antidepressant imipramine hydrochloride 2-fold increased the content of receptor mRNA in genetically cataleptic rats (p<0.

[Effect of changes in the early maternal environment on predisposition to catalepsy in rats of different ages].

Reciprocal cross-fostering of control Wistar and catalepsy-prone GC rat pups resulted in a decrease in duration of cataleptic reactions of GC rats estimated at the age of two weeks, one month, and six months and a tendency to its decrease in Wistar rats at the age of one month. In-fostering did not exert this effect.

Thyroid hormone deficiency determines predisposition to catalepsy in rats.

The role of thyroid hormones in predisposition to cataleptic reaction was investigated. GC rats with genetic predisposition to catalepsy were characterized by decreased serum thyroxin content in comparison with Wistar rats. Thyroidectomy even more reduced the blood concentration of thyroxin in GC rats 30 days postoperation and augmented predisposition to catalepsy in both rat strains.

[Effect of cross-fostering on catalepsy and the brain monoamine level in rat offspring prone to catalepsy and in the control strain].

Duration of cataleptic reactions in male rats of Wistar and GC strains depended both on the genotype and on the type of rearing: it was longer in the GC rats than in the Wistar ones. In the GC males reared by Wistar foster mothers this parameter was smaller than in the control GC but higher than in Wistar rats. The NA content was significantly lower in the GC cortex, hypothalamus and striatum, and the level of serotonin and 5-HIAA was lower in cortex of the GC as compared with Wistar rats.

Some physiological manifestations of the activity of the gene controlling the predisposition to pendulum-like movements in rats.

The physiological actions of the gene controlling the predisposition to stereotypic hyperkinesia in the form of pendulum-like movements (PM) and, probably, a form of spontaneous nystagmus in rats with albinism are manifest as a number of behavioral characteristics (total motor activity, emotionality, startle reflex intensity, sensitivity to serotonin 5-HT2 receptors as assessed in terms of the intensity of head twitching, and predisposition to cataleptic responses). A number of parameters showed differences between hybrids of gray handling-tolerant rats and carriers of the PM gene on the one hand, and between gray rats and animals not carrying the PM gene on the other. Some behavioral characteristics of rats with PM were closer to those of Wistar rats than to those of rats without PM.

[Effect of cross-fostering on various physiological and behavioral features in Wistar and genetically cataleptic rats].

In the GC rats reared by their natural mothers the plasma corticosterone concentration and open field locomotion were lower than in Wistar rats whereas the startle-reflex amplitude was higher. Cross-fostering did not affect the plasma corticosterone concentration or the startle-reflex amplitude. A negative correlation between these parameters was found.

[Physiological manifestations of action of a gene regulating predisposition to a pendulum-like movements in rodents].

Physiological effects of the gene determining predisposition to a stereotypical hyperkinesis in the form of pedulum movements (PM) are manifested in some behavioral peculiarities (total motor activity, emotionality, intensity of the startle reflex, sensitivity of the 5-HT2 receptors, predisposition to catalepsy). High frequency of the PM occurring in Wistar rat stock suggests that the gene determining the PM expression is not a pathological one but controls some adaptive properties of the nervous system. Relationships between the PM expression and the degree of predisposition to catalepsy are biphasic and may be described by an inverted U-shaped curve.

[Genetic relationships between catalepsy and pendulum movements in rats].

Predispositions to pendulum movements (PMs) and catalepsy was studied in rat strains selected for predisposition to catalepsy and for enhanced or suppressed PMs. Positive correlation between PMs and catalepsy at earlier stages of selection changed to negative at later stages. Based on these data, it was hypothesized that the genes that determine the predisposition to catalepsy affect the expression of the gene determining PMs in such a way that different PM alleles become dominant in the cases of moderate and strong effects of the catalepsy genes.

[Inheritance of pendulum movements in rats].

Inheritance of predisposition to pendulum movements (PMs) in rats was studied by two methods: segregation analysis of binary traits (on pedigrees recorded in the selection archives for cataleptic strain GC) and the classical Mendelian analysis of hybrids between strains PM+ and PM- selected for pronounced PMs and the absence of PMs, respectively. Both methods yields the same result: it was found that predisposition to PMs exhibited a monogenic dominant inheritance with incomplete penetrance.

[Relationship between certain forms of catalepsy in rats. An attempt at genetic analysis].

Rats from strain GC selected for predisposition to "pseudocatalepsy" (a cataleptic response to an enforced vertical posture) are also characterized by an increased duration of pinch-induced catalepsy. Expression of catalepsy in F1 and segregation in F2 hybrids obtained from GC x Wistar crossing were analyzed. The results obtained indicate that a monogenic dominant inheritance with incomplete penetrance cannot be ruled out for both pseudocatalepsy and pinch-induced catalepsy.

[Possibility of major gene control over scale E of Cattel's test].

The segregation analysis is made of inheritance of the E factor of the Cattell's 16PF Questionnaire on the basis of a population sample consisting of 108 free-structured pedigrees. The possibility of major gene control of inheritance for this quantitative trait is confirmed.

[Properties of glucose isomerase from Streptomyces robeus S-606].

Optimal conditions of the glucose isomerase fixation in a cell are determined by thermal treatment of Str. robeus S-606 biomass. Under these conditions the maximal enzyme activation (by 50-55 percent) is simultaneously observed.

[Effect of metal ions on the glucose isomerase activity of Streptomyces robeus S-606].

The intracellular glucose isomerase produced by Str. robeus S-606 refers to the group of isomerases activated most effectively by Mg2+. Besides, an activating effect of Fe3+, Co2+ and Mn2+ is observed.