Neurovascular effects of reactive oxygen intermediates produced by photoradiation.
These experiments examined the effect of reactive oxygen intermediates, produced by laser illumination of the photosensitizer hematoporphyrin derivative, on the accumulation and release of norepinephrine from sympathetic nerve terminals. Using an isolated, spirally cut, superfused caudal artery of the rat, basal overflow of norepinephrine (NE) was significantly increased both during and after generation of reactive oxygen intermediates. Generation of reactive oxygen intermediates increased overflow of NE in vascular preparations in which release of NE had previously been elevated by the continuous superfusion of Krebs' solution, containing high concentrations of potassium (40 mM). Calcium free solutions did not block the overflow of norepinephrine augmented by reactive oxygen intermediates. This increase in overflow was due both to an increase in release of NE and an inhibition of accumulation of NE.
Freas
W
W
Department of Anesthesiology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.
Llave
R
R
Hart
J L
JL
Kobayashi
Y
Y
Nagel
J
J
Muldoon
S M
SM
D000818:Animals; D003042:Cocaine / Q000494:pharmacology; D005609:Free Radicals; D006415:Hematoporphyrins / Q000378:metabolism / Q000528:radiation effects; D066298:In Vitro Techniques; D007834:Lasers; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009411:Nerve Endings / Q000187:drug effects / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism*; D010100:Oxygen / Q000528:radiation effects / Q000633:toxicity*; D010477:Perfusion; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013564:Sympathetic Nervous System / Q000187:drug effects*
D005609:Free Radicals; D006415:Hematoporphyrins; D011189:Potassium Chloride; D003042:Cocaine; D010100:Oxygen; D009638:Norepinephrine