[Edematous changes in the ultrastructure of the neocortex of Wistar rats following the application of angiotensin II]. / Odematöse Veränderungen der Ultrastruktur des Neokortex von Wistarratten nach Applikation von Angiotensin II.

In 80 Wistar rats were investigated the prolonged action of Angiotensin II in a dosage of 0,05 mg/kg/die ip. appl. on microstructures of the sensomotoric cortex. It is observed, after the first application, a biphasic reaction of brain vessels, in the beginning a pronounced vasodilatation (5 min p.-inject) which 10 min later turn into a vasoconstriction. In correlation with the applications frequency the repeated injection of the octapeptide leads to perivascular edemas. Neurons of the sensomotoric cortex show strong swellings, which later turn in to involutions. Pronounced destructions of mitochondria are demonstrable. Conceivable mechanisms were discussed.

[Experimental hydrocephalus using prolonged angiotensin II application]. / Experimentelle Hydroenzephalie durch prolongierte Angiotensin II -- Applikation.

In 80 wistar rats were investigated the prolonged action of Angiotensin II in a dosage of 0,05 mg/kg/die ip. appl. on macrostructures of brain. We tested the material 1-, 3-, 7-, 14- and 21 days after the first application. In correlation with duration of the Angiotensin II action a hydroencephalie was produced. This was marked by a lumen, so big as a 1/4-1/5 of the whole brain extent. Further we observed a considerable atrophy of brain structures, particularly in the corpus callosum and the white and gray Substance of cortex. Light-microscopically we would prove edemas perivasculary with separations of ependymal cells. Conceivable mechanisms were discussed.

[Effect of a substance P analog on sleep deprivation]. / Wirkung eines Substanz P-Analogons bei Schlafstörung.

The injection of 250 microgram/kg SP-analogue (Lys-Phe-Ile-Gly-Leu-MetNH2) is able to restore the reduced or disturbed delta activities and paradoxical sleep periods of the sleeping EEG in chronically stressed rats. Thus it has been proved that Substance P, which we would like to term as an ,,regulatory peptide" (equal to regulide) has a modulating function.

[Asymmetric function of the pes hippocampi in experimental stress-induced arterial hypertension of albino rats]. / Zur asymmetrischen Funktion des Pes hippocampi bei experimentell stressinduzierter arterieller Hypertonie von Albinoratten

Relations between a unilateral lesion of circumscribed structures of the Pes hippocampi on the one hand, and stress-induced blood-pressure and learning behaviour, on the other, were studied. An asymmetric functioning of the CNS was analyzed, in which unilateral exclusion of right-hand hippocampal structures stimulates processes of excitation, while lesion of left-hand structures causes prevalence of inhibitory processes. The resulting impairment of the emotional equilibrium potentiates the stress action's contribution to the development of arterial hypertension.

[Diurnal dynamics of periodicities in conditional-reflex processes in the minute range]. / Zur tagesperiodischen Dynamik von Periodizitäten bedingt-reflektorischer Prozesse im Minutenbereich

Male adult albino rats living from the 6th week of their lives under conditions of artificial light-dark cycle (16 hrs light, 8 hrs dark) were used to study possible relationships between circadian sensitivity cycles and synchronization of dynamics and the frequency variability of periodicities of reaction times of conditional-reflectory processes with wavelengths in the minute range. The experiments have revealed differences at the time of the activity maximum and minimum of a circadian cycle in the studied parameters of the minute rhythm (mean level of oscillation, mean amplitude, length of period and coupling). In the dark phase (activity maximum) there prevailed an increased level of central-nervous excitation and a tendency towards a higher frequency and diminished coupling of minute periods. In the light phase (activity minumum) the animals showed a balanced level of excitation, reduced frequency and a rigid coupling of periodicities of conditional-reflectory events involved in the process. Relations are shown to exist between central-nervous processes and circadian sensitivity cycles. For the experimental practice it is concluded that the different times of the day should be accounted for in assessing the criteria of minute rhythm and in conditional-reflectory studies in pharmacology and toxicology.