Table 2.

Cerebrovascular resistance during hypoxia and hypercapnia with pharmacological interventions

	Hypoxia				Hypercapnia
Day	Lead-in	5 min	20 min	Recovery	Lead-in	5 min	20 min	Recovery
Control	1.44 ± 0.34	1.40 ± 0.32	1.42 ± 0.32	1.52 ± 0.31	1.39 ± 0.32	1.14 ± 0.25*	1.20 ± 0.26*	1.63 ± 0.30*
l-NMMA	1.51 ± 0.44	1.44 ± 0.43*	1.42 ± 0.41*	1.51 ± 0.46	1.56 ± 0.51	1.29 ± 0.41*	1.32 ± 0.38*	1.75 ± 0.50*
Phenylephrine	1.50 ± 0.40	1.50 ± 0.37	1.48 ± 0.36	1.55 ± 0.35	1.47 ± 0.29	1.24 ± 0.22*	1.26 ± 0.23*	1.73 ± 0.25*

Values (Torr (cm s⁻¹)⁻¹) are means ±s.d. Cerebrovascular resistance was calculated as MAP divided by . , middle cerebral artery blood velocity associated with the maximum frequency of the Doppler shift; MAP, mean arterial blood pressure.

^*denotes a significant difference from lead-in at P < 0.05.