[The increase in the proportion of nervous animals bred for catatonia: the participation of central adrenoreceptors in catatonic reactions].

Using a large amount of breeding material, the idea of D. K. Belyaev on the role of selection in the appearance of new behavioral and neuronal forms was confirmed. Experiments were performed using rats of the GC (genetics + catatonia) strain, which are prone to passive defensive reactions of cataleptic freezing. At the current breeding stage, elevation of the proportion of so-called nervous animals was demonstrated, both with respect to the expression of such reactions and their frequency. At this breeding stage, in the brains of GC rats, the mRNA levels of alpha1A- and alpha2A-adrenoreceptor genes were determined. A decrease of alpha1A-adrenoreceptor gene expression in the midbrain and medulla oblongata, along with elevation of alpha2A-adrenoreceptor gene expression in the frontal cortex was observed. It was suggested that changes in the expression of alpha-adrenoreceptor genes could be caused by an increase in the proportion of nervous animals and could contribute to the akinetic behavioral component in GC rats.

[Renin-angiotensin system gene expression in the kidney and in the heart in hypertensive ISIAH rats].

The content of mRNA of renin-angiotensin system (RAS) genes in the kidney and heart of hypertensive ISIAH and normotensive WAG rats was measured by the real-time PCR. Statistically significant decrease of RAS gene mRNA was registered in the kidney of ISIAH rats, including Ren (by 45%), Ace (43%), AT1A (34%), COX-2 (50%). In the myocardium AT1A mRNA expression decreased by 28% while Ace mRNA expression increased by 80%. These results demonstrate the reduction of renal RAS basal activity in the hypertensive ISIAH rats, and this allows us to consider the ISIAH rat, as a low-renin hypertensive strain. In support of this viewpoint, in the ISIAH rats, a two-fold increase in the connective tissue sodium concentration as well as statistically significant plasma sodium increase (from 136 +/- 0,25 micromol/l in WAG to 139 +/- 0,3 micromol/l in the ISIAH rats) were found. Our conclusion backed by a tendency of the ISIAH plasma aldosterone level decrease giving in sum a classical picture of a low-renin hypertensive state in the ISIAH rats. It was suggested that the formation of low-renin arterial hypertension in the ISIAH rats may depend on changes in kidney ion channels function. In addition, renal NO system alterations could be also involved in the pathogenesis of arterial hypertension in the ISIAH rats.

[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.

[Typological characteristics of behavior in strains of rats bred for enhancement and absence of pendulum movements. Association with brain monoamines].

Typological characteristics of behavior were studied in rats bred for enhancement (PM+) and absence (PM-) of pendulum movements. Excitement in different test situations was manifest in PM+ rats, whereas passive defensive reactions were characteristic of PM- rats. Increased excitability of PM+ rats was expressed in their greater predisposition to audiogenic epilepsy (83% in PM+ versus 40% in PM- rats). On the contrary, PM- rats were found to be more prone to freezing (61% in PV- versus 11% in PM+). In PM+ rats, noradrenaline and serotonin contents were decreased in hypothalamus (as compared to PM- and control Wistar stain), whereas in PM- rats, serotonin content was increased in striatum, hypothalamus and midbrain as compared to control strains.