[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.