Effects of radiation on endothelial function.
OBJECTIVE
The response of endothelium to ionizing radiation was studied.


METHODS
The abdominal aorta in different experimental groups of rats was irradiated, and the response of arterial rings from the irradiated segments to norepinephrine, acetylcholine (ACh), and nitroglycerin (NTG) was studied. Nonirradiated thoracic segments in the same experimental animals were used as as a control for comparisons. Two age-matched nonirradiated control groups were also studied.


RESULTS
A poor endothelium-dependent vasodilator response was obtained with ACh in the irradiated rings and also in those not directly irradiated; the endothelium-independent vasodilator response to NTG was preserved during the first 3 days after irradiation. By 6 months, both the endothelium-dependent response and endothelium-independent response were impaired.


CONCLUSIONS
Alterations in nitric oxide synthesis and/or release by the endothelium were observed during the early phase of radiation in irradiated and nonirradiated segments. In the delayed phase of radiation, endothelium-independent muscular relaxation was also affected.
Menendez
J C
JC
Department of Radiotherapy, Hospital Universitario M. Valdecilla, Santander, Spain.
Casanova
D
D
Amado
J A
JA
Salas
E
E
García-Unzueta
M T
MT
Fernandez
F
F
de la Lastra
L P
LP
Berrazueta
J R
JR
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects / Q000528:radiation effects; D001013:Aorta, Thoracic / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000528:radiation effects*; D005996:Nitroglycerin / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D005996:Nitroglycerin; D000109:Acetylcholine; D009638:Norepinephrine