Stimulation of α1-adrenergic receptors with injections of phenylephrine (1, 5, 10, 50, 100, 150, and 200 μg kg−1, i.v.) evoked attenuated rises in MAP in rats exposed to CIH (n = 19) compared to control rats (n = 16). *P < 0.05 and **P < 0.01, significant difference from control rats, 2-way repeated measures ANVOA with Tukey–Kramer post hoc tests.