Table 2.

Blood gas values and arterial O₂ content recorded in 7N, 7CH, 18N and 18CH rats

		Pa,O2 (mmHg)	Ca,O2 (ml(100 ml)−1)	Pa,CO2 (mmHg)
7N	Air	82.4 ± 1.3	21.6 ± 0.27	45.7 ± 2.7
	8% O2	31.6 ± 0.1	14.5 ± 0.56	31.3 ± 3.8
7CH	12% O2	39.5 ± 2.2***	22.08 ± 0.47	34.0 ± 1.0**
	8% O2	32.6 ± 1.5	18.28 ± 0.86*	29.0 ± 0.8
18N	Air	85.7 ± 1.8	22.36 ± 0.25	45.4 ± 2.5
	8% O2	32.4 ± 0.9	15.4 ± 0.8	32.6 ± 2.2
18CH	12% O2	40.6 ± 2.6**	19.96 ± 0.6*	34.5 ± 1.5**
	8% O2	30.7 ± 1.8	16.19 ± 1.12	29.6 ± 1.8

7N and 18N rats were switched from breathing air to breathing 8% O₂ for 5 min, while 7CH and 18CH were switched from breathing 12% O₂ to breathing 8% O₂ for 5 min. Blood samples were taken under the respective control conditions at the 5th minute of breathing 8% O₂. Values are given as means ± s.e.m.

^***P < 0.001

^**P < 0.01

^*P < 0.05, significant difference between N and CH rats for values recorded in N rats breathing air and CH rats breathing 12% O₂, or in N and CH rats breathing 8% O₂.