Measurement of local cerebral blood flow with iodo [14C] antipyrine

Abstract

The autoradiographic diffusible tracer technique for the measurement of local cerebral blood flow was originally designed for use with the radioactive, inert gas 131I-labeled trifluoroiodomethane and is applicable only with tracers that exhibit unrestricted diffusion through the blood-brain barrier. Because of the technical problems associated with the use of gaseous tracers, a suitable nonvolatile tracer has been sought. [14C] Antipyrine has been used previously and found to be unsuitable because of limitations in its diffusion through the blood-brain barrier. An analogue of [14C]antipyrine, iodo [14C]antipyrine, exhibits higher partition coefficients than [14C]antipyrine between nonpolar solvents and water and might, therefore, be expected to diffuse more freely through the barrier. Its use as the tracer in the local blood flow technique leads to values considerably above those obtained with [14C]antipyrine in the rat and cat and essentially the same as those obtained with the gas trifluoro[131I]iodomethane in the cat. Iodo[14C]antipyrine appears, therefore, to be a satisfactory nonvolatile tracer for the measurement of local cerebral blood flow.

Reduced Cerebral Blood Flow but Elevated Cerebral Glucose Metabolic Rate in Erythropoietin Overexpressing Transgenic Mice with Excessive Erythrocytosis

“…Moreover, tg-6 mice were hemodiluted by an isovolemic blood exchange at a rate of 0.1 ml min À1 with albumin (Human Albumin 5%, Behring Pharmacia, Erlangen, Germany) to a normal target hematocrit of 0.45 (forming group tg-6-HD). In each group, 16 animals were randomized to be used either for the autoradiographic determination of local CBF (n = 8) or for the measurement of local CMR glc (n = 8), according to the methods described in the rat (Sakurada et al, 1978;Sokoloff et al, 1977). These autoradiographic methods were adapted to mice according to the previous use in this species (Jay et al, 1985(Jay et al, , 1988.…”

The Effects of Serotonin on Local Cerebral Blood Flow

“…The optical densities of 36 discrete areas of the rat brain were determined, using a computer-based densitometer system (Quantimet; Cam bridge Instruments, U.K.). Using this data, and making comparisons with the optical densities of the plastic stan dards and the arterial blood 14C levels, the cerebral blood flow of each region was calculated using the operational equation derived by Kety (1960) and developed for this technique by Sakurada et al (1978).…”

“…Local cerebral blood flow was measured using the 14C-iodo antipyrine quantitative autoradiographic technique of Sakurada et al (1978). The administration of saline or A major problem involved in the study of the ef fects of serotonin on cerebral blood flow is the rela tive impermeability of the blood -brain barrier (BBB) to this monoamine, which is enhanced by the ability of the endothelial cells of the cerebral vessels to catabolize serotonin (Hardebo et aI., 1979;Har debo and Owman, 1980).…”

“…In this study, we have measured the effects of intracarotid administration of serotonin (50 ng kg-I min-I) on blood flow in anatomically discrete areas of the rat brain before and after urea infusion, using the 14C-iodoantipyrine quantitative autoradio graphic method as described by Sakurada et al (1978). The extent of localized BBB permeability caused by urea infusion was also measured in a sep arate group of rats, using the 14C-aminoisobutyric acid (AlB) autoradiographic technique of Blasberg et al (1980).…”

Nicotine Raises the Influx of Permeable Solutes across the Rat Blood—Brain Barrier with Little or No Capillary Recruitment

“…The radiotracers used in this work were 4-[N-methyl Sakurada et al (1978) as modified by Otsuka et al (l991a). Approximately 10 min before beginning the infusion of lAP, an extracorporeal arteriovenous shunt was formed by shortening the femoral artery and vein catheters on one side and connecting them with a 1.2-cm length of silicone rubber tubing.…”