Fig. 2.

(A–C) Time course of arterial carbon dioxide tension after epinephrine administration. Hypercapnia occurs by 10 min at all epinephrine doses without phentolamine pretreatment (P) and by 10 min at the highest epinephrine dose even with pretreatment. Mean values are plotted with error bars indicating SEM; # indicates difference following epinephrine alone from baseline value; + indicates difference in the phentolamine pretreatment group from their baseline value; * indicates difference between the two groups. Symbol number indicates significance: one symbol, P less than 0.05; two symbols, P less than 0.01; three symbols, P less than 0.001.