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The changes of the contents of free amino-acids in the blood of rats of different age groups under various stressogenic factors


Author: Angela Nevoia
Degree:doctor of biology
Speciality: 03.00.13 - Human and animal physiology
Year:2007
Scientific adviser: Valentina Ciochină
doctor, associate professor (docent), Institute of Physiology and Sanacreatology, Academy of Sciences of Moldova
Scientific consultant: Teodor Furdui
doctor habilitat, professor, Institute of Physiology and Sanacreatology, Academy of Sciences of Moldova
Institution:
Scientific council:

Status

The thesis was presented on the 20 April, 2007
Approved by NCAA on the 14 June, 2007

Abstract

Adobe PDF document0.28 Mb / in romanian

Thesis

CZU 612.015.38, 577.122.3, 599.323.4:591.05

Adobe PDF document 0.83 Mb / in romanian
133 pages


Keywords

chronic excessive stress, chronic sparing stress, nociceptive stress, starvation, ontogenesis, free amino acids, plasma, erythrocyte, catabolism, anabolism

Summary

The free amino-acids contents in plasma and erythrocytes of young, adult and senile male Wistar rats in the comfortogenic conditions and under the action of stressogenic factors were studied. The changes in the free amino-acids contents were analysed in the acute excessive stressogenic conditions, as a result of 24 hour immobilization, under chronic nociceptive stress, sparing and excessive, obtained by means of electric footshock and the short-term starvation for 24 and 48 hours. It was revealed that the free amino-acids contents in plasma is different from that in erythrocytes. Alanine and glutamine predominate in plasma, and proline – in erythrocytes. Along with the age, the free amino-acids contents grow continually because of the increase of their concentration in erythrocytes. The maximum concentration of the essential and the non-essential amino-acids was detected in the plasma of the rats of 9 weeks old, the minimum concentration of the essential amino-acids was determined in the rats of 3 weeks old, and the non-essential amino-acids – in the senile ones.

The most considerable changes of the amino-acids contents were determined in the immobilized rats and in those under excessive chronic stress, where the amino-acids contents increased significantly in both the media. The considerable increase of the contents of the essential ketogenic amino-acids, the amino-acids-mediators and the precursors of biogenic amines –γ-amino butyric acid, tryptophan, phenylalanine, ammonia and the amino-acids participating in the synthesis of urea – arginine and ornitine, was characteristic of immobilization. In the excessive chronic stress conditions, the high level of the ketogenic amino-acids was associated with the more enhanced values of the glycogenic amino-acids. The increase of the amino-acids sum in the erythrocytes of the young rats was much more considerable in comparison with that of the adult ones. The chronic sparing stress mostly reflected on the amino-acids contents in erythrocytes. In the young rats, they tended to decrease whereas, in the other age groups, the modifications had bidirectional character. In the young immobilized rats and the senile ones subjected to the excessive chronic stress, the plasma amino-acids contents increase was more considerable in comparison with that of the other age groups whereas the amino-acids contents in erythrocytes diminished. The initial starvation, after 24 hours, determined the decrease of the free amino-acids sum in erythrocytes, then, after 48 hours, the essential amino-acids contents increased in both the media, especially in erythrocytes, and the non-essential amino-acids level decreased in plasma. The changes in the aminogram of the young rats, even after one day of starvation, corresponded with those observed in the adult and in the senile rats after 48 hours. The free amino-acids contents in plasma and erythrocytes and especially their modifications represent a reflection of the substance metabolism of rat organism which reacts to the action of stressogenic factors and has some age peculiarities. It was determined that, in order to obtain a complete characteristic of the nitrogen metabolism, the analysis of the amino-acids contents not only in plasma but also in erythrocytes is necessary.