Sex differences in the cerebral blood flow response after brief hypercapnia in the rat

Hypercapnia primarily affects cerebral blood flow (CBF) and not cerebral me tabolism. We compared the CBF responses due to electrical forepaw stimulati on before and after brief hypercapnia in male, non-ovarectomized female, an d ovarectomized female rats. Prior to hypercapnia the CBF responses were si milar for all th ree groups. Seven minutes after brief hypercapnic exposure the CBF responses to forepaw stimulation were augmented in all groups. How ever, both 30 and 60 min after hypercapnia, the magnitude of the CBF respon ses to forepaw stimulation remained elevated for males and ovarectomized fe males, but not for non-ovarectomized females. These results suggest that es trogen may modulate the upregulation of the CBF response observed after tra nsient hypercapnia. (C) 2001 Elsevier Science Ireland Ltd. All rights reser ved.