Autoradiographic determination of regional cerebral blood flow in the immature rat.
Seven-day-old rats (15 g body weight) were injected subcutaneously with iodo-[14C] antipyrine (5 microCi). After a variable period, each pup was decapitated and arterial blood collected for scintillation counting. Brains were immediately removed and either prepared for isotopic counting or frozen for autoradiography. The brain:blood partition coefficient was determined [0.944 +/- 0.006 ml/g (mean +/- SEM)]. Both cerebral blood flow (CBF) and regional CBF (RCBF) were calculated according to a formula derived from the Fick equation. CBF equaled 66 +/- 4 ml/100 g/min (mean +/- SEM), a value midway between reported 1-day-old rat CBF and adult rat CBF. Autoradiographs were of sufficient quality to permit microdensitimetric readings of a minimum of 11 structures. RCBF ranged from 20 ml/100 g/min in subcortical white matter to 71 ml/100 g/min in the brain stem. Immature rat RCBF, as a proportion of adult rat RCBF, was greatest in brain stem. Previously thought not feasible, this technique provides a reliable and relatively simple means of measuring both CBF and RCBF in the very small laboratory animal.
D000818:Animals; D000983:Antipyrine / Q000031:analogs & derivatives; D001345:Autoradiography; D002545:Brain Ischemia / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D002534:Hypoxia, Brain / Q000503:physiopathology; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow
D000983:Antipyrine; C008135:iodoantipyrine