Attenuation of hypoxic response in cerebral microcirculation following deprenyl.
Cerebral blood flow (CBF), cerebrocortical microflow (CMF) and local pO2 were measured in the rat brain cortex during normoxia and hypoxic hypoxia before and after administration of the monoamine oxidase-B (MAO-B) inhibitor deprenyl (0.1 mg/100 g b.wt. i.v.). CBF was measured using intraarterial 133-Xenon injection technique. Both, CMF and pO2 were measured using polarographic multiwire surface electrodes. In the control group without deprenyl CBF increased during hypoxaemia (PaO2 = 44.7 +/- 9.3 mm Hg) by 215% while CVR decreased to 27% of the normoxic control value. Hypoxaemia (PaO2 = 34.4 +/- 3.9 mm Hg) also led to a mean increase of CMF by 38% of the normoxic control (p less than 0.02) while the local cerebrocortical pO2 fell from 20.1 +/- 5.1 mm Hg to 5.2 +/- 1.9 mm Hg (p less than 0.02). The administration of deprenyl during normoxia did not cause any significant changes of CBF and CMF although both increased by 29% and 28%, respectively. The increase of CBF during hypoxaemia (PaO2 = 34.9 +/- 6.3 mm Hg) following deprenyl administration, although diminished, was still present (101%, p less than 0.01). CMF decreased under these conditions by 30% on average (p less than 0.05). These results suggest that MAO-B may be involved in the local regulation of cerebrocortical capillary blood flow during hypoxia.
Höper
J
J
Institut für Physiologie und Kardiologie, Universität Erlangen-Nürnberg.
Kozniewska
E
E
D000818:Animals; D015687:Cell Hypoxia / Q000187:drug effects*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D000860:Hypoxia / Q000097:blood; D008297:Male; D008833:Microcirculation; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D051381:Rats; D011919:Rats, Inbred Strains; D012642:Selegiline / Q000494:pharmacology*
D012642:Selegiline; D010100:Oxygen