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Uptake of radiolabeled ions in normal and ischemia‐damaged brain
Author(s) -
Dienel Gerald A.,
Pulsinelli William A.
Publication year - 1986
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410190507
Subject(s) - ischemia , striatum , hippocampus , forebrain , chemistry , endocrinology , medicine , brain ischemia , anesthesia , central nervous system , dopamine
The regional concentrations of nine radiochemicals were measured in rat brain after induction of cerebral ischemia to identify tracers concentrated by brain undergoing selective neuronal necrosis. Transient (30 minute) forebrain ischemia was produced in the rat; 24 hours after cerebral recirculation the radiochemicals were injected intravenously and allowed to circulate for 5 hours. The brain concentrations of the radiochemicals in dissected regions were determined by scintillation counting. Forebrain ischemia of this nature will produce extensive injury to striatal neurons but will spare the great majority of neocortical neurons at 24 hours. The regional concentrations of these radiochemicals varied considerably in both control and ischemic animals. In postischemic animals, 4 radionuclides ( 63 Ni, 99 TcO 4 , 22 Na, and [ 3 H]tetracycline) were concentrated in the irreversibly damaged striatum in amounts ranging from 1.4 to 2.4 times greater than in normal tissue. The concentrations of 65 Zn, 59 Fe, 32 PO 4 , and 147 Pm in postischemic brain were similar to or less than those in normal brain. The concentration of [ 14 C]EDTA was increased in injured and uninjured brain of postischemic rats. Autoradiographic analysis of the distribution patterns of some of these ions in normal animals showed that 99 TcO 4 , 22 Na, 65 Zn, and 59 Fe were distributed more uniformly throughout the brain than were 32 PO 4 , 63 Ni, and 147 Pm. At 24 or 48 hours after ischemia, 63 Ni, 99 TcO 4 , and 22 Na were preferentially concentrated in the damaged striatum and hippocampus, whereas 65 Zn, 59 Fe, 32 PO 4 , and 147 Pm did not accumulate in irreversibly injured tissue. Of the radiochemicals tested to date, Ni, TcO 4 , and tetracycline may be useful for diagnosing ischemic brain injury in humans, using positron emission tomography.