Additive wake-promoting effects of α1- and β-agonist receptor stimulation within the MSA and MPOA. Panels depict the wake-promoting effects of vehicle, 10 nmol of the α1-agonist, phenylephrine (PHEN), 4 nmol of the β-agonist, isoproterenol (ISO), and combined PHEN + ISO (Combined) when infused into the MSA (Top Panel) and MPOA (Bottom Panel). For both regions, a relatively low dose of each drug was used that elicited only a mild wake-promoting action when administered alone. In the combined treatment group, additive wake-promoting effects of ISO and PHEN were observed. Symbols represent means (± SEM) of time (seconds) spent awake per 30-min testing epoch. PRE1 and PRE2 represent 30-minute pre-infusion epochs occurring immediately prior to the infusion. POST1-POST3 represent 30-minute post-infusions epochs, beginning immediately following the infusions. *P<0.05, **P<0.01 compared to PRE1; +P<0.05 compared to Combined (from34).