[Involvement of nitrogen oxide in the cerebral vasoconstriction during respiration with high pressure oxygen].
High pressure oxygen evokes a cerebral vasoconstriction and diminishes cerebral blood flow with the aid of mechanisms which are not yet sufficiently studied. We were checking a hypothesis that the hyperbaric oxygen (HBO2) inactivates cerebral nitrogen oxide (NO), interrupts its basal relaxing effect, and evokes a vasoconstriction. In our experiments, HBO2 decreased cerebral blood flow depending on the pressure. Inhibiting the NO-synthase weakened basal vasorelaxation in breathing with atmosphere air and eliminated the vasoconstriction in exposure to the HBO2. Inactivation of O2 prevented the HBO2-induced vasoconstriction. The data obtained reveal that diminishing of cerebral blood flow in HBO is related to the NO inactivation and weakening of its basal vasorelaxing effect. Possible mechanisms of the NO inactivation may involve its reaction with oxygen and superoxide anion which lead to diminishing of the tissue NO concentration and weakening of its vasorelaxing effect.
Demchenko
I T
IT
I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Acad. Sci., 194223, St. Petersburg, pr. M. Toreza, 44, Russia.
Bosso
A E
AE
Zhiliaev
S Iu
SIu
Moskvin
A N
AN
Gutsaeva
D R
DR
Atochin
D N
DN
Bennett
P B
PB
Piantadossi
K A
KA
D000758:Anesthesia; D000818:Animals; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010100:Oxygen / Q000494:pharmacology*; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000502:physiology*; D014851:Wakefulness
D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D010100:Oxygen
Rol' oksida azota v tserebral'noĭ vazokonstriktsii u krys pri dykhanii kislorodom pod davleniiem.