FIG. 8.

Effects of sustained hypoxia (SH) on hypoxia-evoked CA secretion from neonatal chromaffin cells. A and B: examples of hypoxia-evoked CA secretion from chromaffin cells from P5 rats reared under normoxia (control) or SH (5days). Horizontal black bars represent the duration of hypoxic challenge (Po₂ ≃ 30 mmHg). C and D: average data of the effects of graded hypoxia: the number of secretory events/min (C) and average CA molecules released per event (D). Po₂ = partial pressure of oxygen (mmHg) of the superfusing medium. Data shown are means ± SE from 17 cells (control) and 18 cells (SH) obtained from 3 different litters in each group. *P < 0.01; **P < 0.001; n.s., not significant (P > 0.05).