EN
It has been found in the previous works (1, 2, 3) that E. coli cells labelled with radiochromium do not penetrate through intestinal wall of guinea-pigs. In rats, in similar conditions, about 10-20% of the radioactivity connected with labelled E. coli cells, introduced into stomach, disappeared from inner diameter of intestine in consequence of penetration, together with bacterial elements, into organism interior. Since, in the light of the investigations carried out previously (4), the supposed penetration of free radiochromium separated from cells by enzymatic action cannot take place, it must be assumed that intestinalwall of rats would have a limited physiologic tolerance for penetrai bacterial elements. The intensive penetration in white rats (about 40%), appearing a constant reaction, was observed in consequence of effect of subci neously administered exogenic histamine. Further consecutive examinations of rats during anaphylactic shock showed intensive penetration of radioactive elements through intes wall, within the limits of 37-70% only in 28% of used animals, what proves that the rats show an individual response to the endog histamine effect, probably depending on the dynamics of its release from cells.The aim of the present study, as a further development of the subejct was to investigate the effect of other stress factors on functionality changes of intestine wall as an antibacterial barrier.