Brain uptake of radiolabeled amino acids, amines, and hexoses after arterial injection

Oldendorf, WH

doi:10.1152/ajplegacy.1971.221.6.1629

Cited by 1,638 publications

(584 citation statements)

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“…In the brain at least, PEA is found at a concentration many hundred-fold lower than DA, NE, or 5-HT in the extracellular space of (i.e. 2 -15 nM, Henry et al, 1988;Scarr et al, 1994) likely having diffused to its site of synthesis in the cytoplasm and through the plasma membrane (Oldendorf 1971;Boulton & Baker, 1975) given its lipophilic nature (Mack & Bonsich, 1979;Paterson et al, 1990).…”

Section: Biosynthesis and Turnover Of The Trace Aminesmentioning

confidence: 99%

Trace amine-associated receptor 1—Family archetype or iconoclast?

Grandy

2007

Pharmacology & Therapeutics

179

211

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Interest has recently been rekindled in receptors that are activated by low molecular weight, noncatecholic, biogenic amines that are typically found as trace constituents of various vertebrate and invertebrate tissues and fluids. The timing of this resurgent focus on receptors activated by the 'trace amines' (TAs) β-phenylethylamine (PEA), tyramine (TYR), octopamine (OCT), synephrine (SYN), and tryptamine (TRYP) is the direct result of two publications that appeared in 2001 describing the cloning of a novel G protein-coupled receptor (GPCR) referred to by their discoverers as TA1 (Borowsky et al., 2001) and TAR1 (Bunzow et al., 2001). When heterologously expressed in Xenopus laevis oocytes and various eukaryotic cell lines recombinant rodent and human TA receptors dosedependently couple to the stimulation of cAMP production. Structure-activity profiling based on this functional response has revealed that in addition to the TAs, other biologically active compounds containing a 2 carbon aliphatic side chain linking an amino group to at least one benzene ring are potent and efficacious TA receptor agonists with amphetamine, methamphetamine, 3-iodothyronamine, thyronamine, and dopamine among the most notable. Almost 100 years after the search for TA receptors began numerous TA1/TAR1-related sequences, now called Trace AmineAssociated Receptors (TAARs), have been identified in the genome of every species of vertebrate examined to date. Consequently, even though heterologously expressed TAAR1 fits the pharmacological criteria established for a bona fide TA receptor a major challenge for those working in the field is to discern the in vivo pharmacology and physiology of each purported member of this extended family of GPCRs. Only then will it be possible to establish whether TAAR1 is the family archetype or an iconoclast.

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Section: Biosynthesis and Turnover Of The Trace Aminesmentioning

confidence: 99%

Trace amine-associated receptor 1—Family archetype or iconoclast?

Grandy

2007

Pharmacology & Therapeutics

179

211

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“…Both DG and FDG are transported from blood to brain in a manner analogous to glucose (Bidder, 1968; Bachelard, 1971;Oldendorf, 1971; Horton et aI., 1973). Both compete for hexokinase for phos phorylation to DG-6-P and FDG-6-P, re spectively (Bessell et aI., 1972; Re ivich et aI., 1979) but be cause FDG-6-P and DG-6-P cannot be transported through the cell membrane and are not metabolized fu rther through the glycolytic pathway, they are…”

mentioning

confidence: 99%

Effect of Ischemia on Quantification of Local Cerebral Glucose Metabolic Rate in Man

Hawkins

Phelps

Huang

et al. 1981

J Cereb Blood Flow Metab

145

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Summary:The model for quantifying local cerebral glucose metabolic rates originally developed by Sokoloff et aL and modified by Phelps, Huang and co-workers was applied to humans with cerebral ischemia (i.e" stroke), Rate constants for fluorodeoxyglucose were measured in ischemic and nonischemic regions with positron computed tomography, Using measured rate constants for ischemia. the model generates more accurate estimates of local cerebral glucose metabolism as compared to the use of rate constants from normal young adults, because the local metabolic rate is significantly underestimated, and temporal instability of the model is observed when normal values are applied to ischemic regions. A method was also developed to test the stability of the local lumped constant. The estimates of the lumped constant showed no or only small variations between ischemic and nonischemic types. Thus, errors introduced in the calculated local cerebral glucose metabolism by inappropri ate rate constants appear to be more significant than those caused by any potential change in the lumped constant in ischemia.The method of tomographic measurement of the local ce rebral metabolic rate fo r glucose (LCMRGlc) provides, for the first time, a noninva sive method of evaluating local ce rebral metabolism in humans in vivo. The technique has been pre vi ou sly described (Phelps et aI., 1979; Re ivich et aI. , 1979;Huang et al. 1980) and is an extension of the deoxyglucose autoradiographic approach for the me asurement of LCMRGlc (Sokoloff et aI., 1977(Sokoloff et aI., , 1979.The model provides a measurement of LCMRGlc in animals, with [14C]deoxyglucose (DG), or in man, with [18F]fluorodeoxyglucose (FDG), if the fo llow ing parameters are known (parameters will be dis cu ssed only in terms of FDG): (i) the total local Address correspondence and reprint requests to Dr. Phelps at UCLA School of Medicine. Division of Nuclear Medicine: Los Angeles. California 90024.Ahhreviations used: DG, 2-Deoxyglucose: FOG. Fluorode oxyglucose; FDG-6-P, Fluorodeoxyglucose-6-phosphate; G-6-P. Glucose-6-phosphate; LC. Lumped constant; LCMRGlc, Local cerebral metabolic rate for glucose, 37tissue radioactivity co ncentration of IHF [FDG plus FDG-6-phosphate (FDG-6-P)] and the capillary plasma FDG concentration as a fu nction of time; (ii) rate constants for fo rward and reverse transport between plasma and tissue (k� and k�) and fo r phos phorylation of FDG and dephosphorylation of FDG-6-P (ktl and k�); and (iii) the "lumped co n stant" (LC), which is a ratio of arteriovenous ex traction fraction of FDG to that of gluco se under steady-state conditions when k� is small. LC is a term that accounts for the differences in transport and phosphorylation between glucose and FDG.Both DG and FDG are transported from blood to brain in a manner analogous to glucose (Bidder, 1968; Bachelard, 1971;Oldendorf, 1971; Horton et aI., 1973). Both compete for hexokinase for phos phorylation to DG-6-P and FDG-6-P, re spectively (Bessell et aI., 1972; Re ivich et aI., 1979) but...

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“…Simul taneously, transport across the blood-brain barrier becomes the rate-limiting factor of metabolism (Gjedde, 1982;Pardridge et aI., 1982). Although transport of DG is �40% faster than that of glucose (Oldendorf, 1971), blood-brain barrier damage is unlikely to affect transport of the two similar chem ical species (glucose and DG) differently. DG is phosphorylated by hexokinase at a slower rate than glucose (Sols and Crane, 1954).…”

Section: Discussionmentioning

confidence: 98%

Effect of Ischemia and Reperfusion on λ of the Lumped Constant of the [¹⁴C]Deoxyglucose Technique

Greenberg¹,

Hamar²,

Welsh

et al. 1992

J Cereb Blood Flow Metab

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Summary: We measured the parameter A, which is the ratio of the distribution spaces of2-deoxY-D-glucose (DG) and glucose in the brain, in a model of focal cerebral ischemia in the cat. A is the parameter in the lumped constant of the [14C]DG technique most susceptible to changes in ischemia. Cats were subjected to occlusion of the middle cerebral artery for a period of 2 h. During the last 60 min of occlusion, [14C]DG was infused in a pro grammed fashion so as to obtain a stable arterial blood [14C]DG concentration. The brain was funnel-frozen to preserve tissue metabolites and the frozen brain was sam pled regionally (4 to 7-mg samples) for local concentra tions of glucose, ATP, phosphocreatine (PCr), and lac-

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Brain uptake of radiolabeled amino acids, amines, and hexoses after arterial injection

Cited by 1,638 publications

References 0 publications

Trace amine-associated receptor 1—Family archetype or iconoclast?

Trace amine-associated receptor 1—Family archetype or iconoclast?

Effect of Ischemia on Quantification of Local Cerebral Glucose Metabolic Rate in Man

Effect of Ischemia and Reperfusion on λ of the Lumped Constant of the [¹⁴C]Deoxyglucose Technique

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Brain uptake of radiolabeled amino acids, amines, and hexoses after arterial injection

Cited by 1,638 publications

References 0 publications

Trace amine-associated receptor 1—Family archetype or iconoclast?

Trace amine-associated receptor 1—Family archetype or iconoclast?

Effect of Ischemia on Quantification of Local Cerebral Glucose Metabolic Rate in Man

Effect of Ischemia and Reperfusion on λ of the Lumped Constant of the [14C]Deoxyglucose Technique

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Effect of Ischemia and Reperfusion on λ of the Lumped Constant of the [¹⁴C]Deoxyglucose Technique