[Effects of combined stress of high +Gz and noise on learning and memory in rats].
OBJECTIVE
To study the effect of combined stress of noise and + Gz on learning and memory in rats.


METHODS
Thirty-two male SD rats were randomly divided into 4 groups: control group, +10 Gz/3 min group, 90 dB(A)/30 min noise group, combined stress group (+10 Gz/3 min and 90 dB(A)/30 min), 8 rats in each group. Changes of learning and memory after stresses were measured by means of Y-maze test, open field test and step-through test.


RESULTS
As compared with control group and noise group, the number of correct reactions decreased significantly (P<0.01) and the reaction time increased significantly (P<0.01) in combined stress group at all time after stress; time stay in center grille (TSCG) increased significantly immediately after stress (P<0.01). When compared with control group, total time (TT) and number of error (NE) increased significantly (P<0.01) while latent time (LT) decreased significantly immediately and 6 d after stress (P<0.01). As compared with +10 Gz group, number of correct reactions in combined stress group decreased significantly (P<0.05) and reaction time increased significantly (P<0.01) immediately after stress.


CONCLUSIONS
It is suggested that combined stress of noise and +Gz may impair learning and memory of rats, and +Gz seems to contribute more to the combined effects.
Department of Aerospace Biodynamics, The Fourth Military Medical University, Xi'an, China.
Ting-song
TS
Liu
Xi-qing
XQ
Sun
Xin-sheng
XS
Cao
Xing-yu
XY
Wu
D000054:Acceleration; D000818:Animals; D018471:Hypergravity / Q000009:adverse effects*; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D009622:Noise / Q000009:adverse effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology*; D013997:Time Factors