Postradiation regional cerebral blood flow in primates
Early transient incapacitation (ETI) is the complete cessation of performance during the first 30 min after radiation exposure and performance decrement (PD) is a reduction in performance at the same time. Supralethal doses of radiation have been shown to produce a marked decrease in regional cerebral blood flow in primates concurrent with hypotension and a dramatic release of mast cell histamine. In an attempt to elucidate mechanisms underlying the radiation-induced ETI/PD phenomenon and the postradiation decrease in cerebral blood flow, primates were exposed to 100 Gy (1 Gy = 100 rads), whole-body, gamma radiation. Pontine and cortical blood flows were measured by hydrogen clearance, before and after radiation exposure. Systemic blood pressures were determined simultaneously. Systemic arterial histamine levels were determined preradiation and postradiation. Data obtained indicated that radiated animals showed a decrease in blood flow of 63% in the motor cortex and 51% in the pons by 10 min postradiation. Regional cerebral blood flow of radiated animals showed a slight recovery 20 min postradiation, followed by a fall to the 10 min nadir by 60 min postradiation. Immediately, postradiation systemic blood pressure fell 67% and remained at that level for the remainder of the experiment. Histamine levels in the radiated animals increased a hundredfold 2 min postradiation. This study indicates that regional cerebral blood flow decreases postradiation with the development of hypotension and may be associated temporally with the postradiation release of histamine.
- Research Organization:
- Armed Forces Radiobiology Research Institute, Bethesda, MD
- OSTI ID:
- 5203480
- Journal Information:
- Aviat., Space Environ. Med.; (United States), Journal Name: Aviat., Space Environ. Med.; (United States) Vol. 6; ISSN ASEMC
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINES
ANIMALS
AZOLES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BLOOD FLOW
BLOOD PRESSURE
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
CEREBRUM
DOSES
ELECTROMAGNETIC RADIATION
EXTERNAL IRRADIATION
GAMMA RADIATION
HETEROCYCLIC COMPOUNDS
HISTAMINE
HYPOTENSION
IMIDAZOLES
IONIZING RADIATIONS
IRRADIATION
LETHAL DOSES
MAMMALS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PRIMATES
RADIATION EFFECTS
RADIATIONS
VERTEBRATES
WHOLE-BODY IRRADIATION