ВЛИЯНИЕ ДОФАМИНА ПРИ БЛОКАДЕ A-АДРЕНОРЕЦЕПТОРОВ НА ИНОТРОПНУЮ ФУНКЦИЮ СЕРДЦА РАСТУЩИХ КРЫС

29,58±4,48; 8 Gy 27,82±4,95 (p=0,74). In the next test two hours 

later in the “Safe” context all the groups demonstrated low level of 
freezing comparable with such throughout 30 sec before the shock during 
training: Control 4,41±1,39; 1 Gy 3,79±1,61; 8 Gy 3,75±2,40 

(p=0,96). In the third test in the “Similar” context all three groups 
did not differ from each other:
Control 20,47±2,46; 1 Gy 
23,33±1,91; 8 Gy - 26,27±6,78 (p=0,59). The fact that all three groups 
did not discriminate “Dangerous” and “Similar” contexts (p=0,69) 
indicates profound similarity of these contexts. The subsequent 
repeated testing was performed in order to teach the animals to 
differentiate the contexts. However the repeated placement of mice in 
the “Safe” context demonstrated an increase of freezing in all groups, 
without significant intergroup differences: Control - 15,64±2,57; 1 Gy 
- 16,14±4,27; 8 Gy - 17,32±6,64 (p=0,97). During the second placement 
of the animals in the “Similar” context the level of freezing of all 
three groups became significantly higher (p<0,04) than when the animals 
were placed in the “Dangerous” context. Time of freezing in this case 
was also similar between the groups: Control 37,46±3,99; 1 Gy 
45,90±4,25; 8 Gy - 44,71±9,21 (p=0,53).

The obtained results demonstrate that 5 weeks after gamma 

irradiation with the doses 1 Gy and 8 Gy all the groups showed similar 
abilities to remember “Dangerous” context after learning in weak 
contextual 
fear 
conditioning 
task, 
although 
our 
earlier 
data 

demonstrated that the level of cell proliferation in the dentate gyrus 
in 8 Gy group was significantly reduced. It was previously shown [3] 
that mice irradiated with fast neutrons and tested in a similar 
contextual fear conditioning task demonstrated significant memory 
deficit in the learning context on the 1st and 7th days after 
irradiation but not on the 14th day. Thus, our data and the data of 
other authors [3] may indicate that the remaining proliferative 
activity can compensate for the lack of young neurons 2-6 weeks after 
irradiation. Besides, we found that retesting procedure in these 
conditions does not allow animals to differentiate "Dangerous" and 
"Similar" contexts, and leads to a strong generalization of fear among 
all the three groups of mice.

REFERENCES
1.
Deng W., Aimone J.B., Gage F.H. // Nat. Rev. Neurosci., 

2010, 11(5):339-50.

2.
Kim J.S., Yang M., Kim S.H., et al. // Histol. 

Histopathol., 2013, 28(3):301-10. 

3.
Yang M., Kim H., Kim J., et al. // J. Vet. Sci., 2012, 

13(1):1-6.

DOI:10.12737/12303

ВЛИЯНИЕ ДОФАМИНА ПРИ БЛОКАДЕ Α-АДРЕНОРЕЦЕПТОРОВ НА ИНОТРОПНУЮ 

ФУНКЦИЮ СЕРДЦА РАСТУЩИХ КРЫС

Г.А. Билалова, Ф.Г. Ситдиков, Н.Б. Дикопольская, Т.Л. Зефиров