RA treatment and the percentage of dopaminergic neurons increased to 15% compared with 0.8%
in normal oxygen content (20%) 2. In contrast with intermittent hypoxia, continuous hypoxia
inhibited the proliferation about up to 38%, fewer neurons (<80%) were induced and the
percentage of dopaminergic neurons decreased. Conclusions: These results suggest that different
hypoxia conditions had the different effects on neural development. The mechanism of this
interesting phenomenon was going on with gene chips. This work was supported by key grant of
National Nature Science Foundation of China. (30393130)
254.
EFFECT OF ACUTE HYPOXIA ON MAXIMAL EXERCISE IN TRAINED AND
SEDENTARY WOMEN. Woorons Xavier
1
, Mollard Pascal
1
, Lamberto Christine
2
, Letournel
Muriel
3
, Richalet Jean-Paul
1
. EA
23
6
3
, ARPE, Université Paris
13
, Bobigny, France.
1
, EA
23
6
3
,
Hôpital Avicenne, AP-HP, Université ¨Paris
13
, Bobigny, France.
2
, Hôpital Avicenne, AP-HP,
Bobigny, France.
3
.
The purpose of this study was to determine the physiological responses in sedentary and
endurance trained females subjects during maximal exercise at different levels of acute hypoxia.
Fourteen women, sea level residents, were divided into two groups according to their level of
fitness: 1) endurance trained women (TW) (n=7), VO2max = 56.3 ± 4.7 ml.kg -1.min -1 ; 2)
sedentary women (SW) (n=7), VO2max = 34.8 ± 5.6 ml.kg -1.min -1 . Subjects performed four
maximal cycle ergometer tests in normoxia and under hypoxic conditions (FIO2=0.187, 0.154,
and 0.117 corresponding to an altitude of 1000m, 2500m and 4500m respectively). VO2max and
maximal heart rate (HRmax) decreased from 1000m in the two groups. The decrease in VO2max
(delta VO2max) was greater in TW at 2500m and 4500m. Arterial O2 saturation (SpO2) at
maximal exercise was lower in TW at every FIO2. Sea level VO2max and SpO2 were correlated
to delta VO2max at 4500m and 2500m but not below. Furthermore, the decrease in HRmax was
correlated with delta VO2max at 4500m only. Finally, we noted a relationship between SpO2 and
VO2max on one hand, and SpO2 and O2 pulse (VO2/HR) on the other hand at every FIO2. These
results clearly demonstrate that, in acute hypoxia, endurance trained women show a greater
decrement in VO2max. At and above 2500m, this larger decrement would be due, for a great part,
to a higher arterial desaturation, which is largely caused, according to our results, by a diffusion
limitation. However, at 4500m, a decrease in HRmax and maximal cardiac output may play an
important role in the drop of VO2max .
255.
RELAXATION EFFECTS OF AGMATINE ON PULMONARY ARTERIAL RINGS OF
CHRONIC HYPOXIC RATS. Dekun Xiang
1
, Yuqi Gao
1
, Qingyuan Huang
1
, Fuyu Liu
1
.
Department of Pathophysiology and High Altitude Physiology, Third Military Medical
University, Chong
1
.
To explore the effect of agmatine on isolated pulmonary arterial rings from rats with hypoxia-
induced pulmonary hypertension. Methods: Pulmonary arterial were isolated from Wistar rats,
which had been exposured to simulated high altitude of 5000m for 21 days, 23h/d. Cut the artery
into rings and the isometric tension was recorded on the computer equipped Chart Software
(Powerlab). Results AGM(10-8~2_10-3 mol/L) relaxed phenylephrine preconstricted pulmonary
arterial rings in a concentration-dependent manner. The relaxation effect of AGM was
significantly stronger in pulmonary arterial ring from chronic hypoxic rat than that from
normoxic rat(P<0.01). Chronic hypoxic exposure enhance pulmonary reactivity to AGM, the
related mechanisms remains to be explored (By grant of NSFC No. 39730190 and 30393131) .
256.
CLINICAL STUDY OF THE DELAYED RESUSCITATION IN SEVERE BURN PATIENTS
WITH MULTIPLE ORGAN DYSFUNCTION SYNDROMES AT HIGH ALTITUDE . Zhang
Xianying
1
, Liu Yi
1
, Zhang Shifan
2
, Yu Cheng
1
, Cai Qian
1
, Zhang Bin
1
. Department of Burns and
Plastic Surgery, Lanzhou General Hospital of PLA
1
, Department of Thoracic Cardiovas Surgery,
Lanzhou General Hospital of PLA
2
.
