Circadian system of SHR rats

The suprachiasmatic nuclei (SCN) harbor the master circadian pacemaker in mammals which is responsible for control and coordination of circadian rhythms throughout the body and ensure optimal functioning of the organism in variable external conditions. The SCN is a heterogeneous structure in its morphology and function. The present thesis focuses on comparison of the SCN and its properties in an animal model of pathological hypertension, i.e. in spontaneously hypertensive rat (SHR), and nonpathological normotensive Wistar rat. To determine selected morphological and functional markers in the SCN between both rat strains, in situ hybridization and immunohistochemistry methods were used. To compare functional properties of the SCN of SHR and Wistar rat, the effect of light pulses on the expression of c-fos and Per1 genes as well as on locomotor activity were studied in both strains. Our results suggest morphological differences in the number of neurons and in the expression of Avp a Vip in the SCN with an apparent tendencies to higher levels of the studied peptides in SHR compared to Wistar rat. Our data further indicate variation in functioning of the SCN in SHR and Wistar rat on the basis of different responses to light pulses administered in the first part of the subjective night, namely in the..