Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AMINOISOBUTYRIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources
PubMed1980

Anti-inflammatory drugs alter amino acid transport in HTC cells.

Following the addition of indomethacin to exponentially growing rat hepatoma cell (HTC) cultures, cells accumulated in the G1 phase. Over the course of several hours, specific changes in membrane transport accompanied this inhibition. Indomethacin stimulated the uptake of 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (BCH), inhibited the Na+-dependent active transport of alpha-aminoisobutyric acid (AIB), and methylaminoisobutyric acid (MeAIB), but had no effect on the uptake of thymidine, uridine, or 2-deoxyglucose. The stimulation of BCH transport was immediate and reversible. The uptake of BCH was Na+-independent and only slightly depressed by metabolic inhibitors (10 to 20%). Inhibition of AIB and MeAIB uptake, which was of gradual onset, and was observed with several anti-inflammatory drugs and was dependent on the concentration of drugs. Upon removal of drug, AIB and MeAIB transport gradually increased and reached a maximum prior to resumption of DNA synthesis and cell division. Thee effects involved changes in Vmax only. Neither the apparent affinity (Km) for amino acids nor rate of exodus (k, 0.7h-1 for BCH, 1.2h-1 for AIB) were altered. The uptake of MeAIB (and AIB) occurred by a low and a high affinity (Km = 0.27 mM) component. Indomethacin inhibited specifically the high affinity component which was shown to be Na+- and energy-dependent. Although this component was inhibited by treatment with agents that lowered ATP levels or blocked protein synthesis, the anti-inflammatory drugs appeared not to act through these mechanisms.

Amino Acids↗
PubMed1979

Placental transfer of analogs of glucose and amino acids in experimental intrauterine growth retardation.

We have employed the model in which one uterine artery is ligated to study maternofetal transport and tissue uptake of glucose and amino acids in the intrauterine growth-retarded rat. On the 18th day of gestation, the artery supplying one uterine horn was ligated. Two days later the rats received [3H]2-deoxyglucose and [14C]alpha-aminoisobutyric acid iv. One hour later the growth-retarded and control fetuses were delivered by Cesarean section and appropriate blood samples were obtained. The growth-retarded fetuses had an average weight reduction of 27%, significantly increased placental to fetal weight ratio and brain to body ratio, and a significantly reduced liver to body body ratio. Total radioactivity derived from tritiated deoxyglucose in whole fetal tissues, placenta, liver, and brain were significantly decreased in the intrauterine growth-retarded (IUGR) fetuses; this was also true per gram of tissue except for liver. Liver to plasma, brain to plasma, and whole fetal tissue to plasma 3H ratios were significantly increased in the IUGR group. The radioactivity derived from [14C]alpha-aminoisobutyric acid was significantly reduced in whole fetal tissues, placenta, liver, and brain in the IUGR fetuses whether expressed per whole organ or per gram of tissue. Significant differences in liver to plasma, brain to plasma, and whole tissue to plasma 14C ratios were not observed.

Aminoisobutyric Acids↗
PubMed1970

Stability and comparative transport capacity of cells, mureinoplasts, and true protoplasts of a gram-negative bacterium.

The outer layers of the cell envelope of a pseudomonad of marine origin were removed by washing the cells in 0.5 m NaCl followed by suspension in 0.5 m sucrose. The term mureinoplast has been suggested for the rod-shaped forms which resulted from this treatment. As previously established, these forms lacked the outer cell wall layers but still retained a rigid peptidoglycan structure. Mureinoplasts remained stable if suspended in a balanced salt solution containing 0.3 m NaCl, 0.05 m MgSO(4), and 0.01 m KCl but, unlike whole cells, lost ultraviolet (UV)-absorbing material if suspended in 0.5 m NaCl or 0.05 m MgCl(2). Sucrose added to the balanced salt solution also enhanced the loss of UV-absorbing material. Addition of lysozyme to suspensions of mureinoplasts in the balanced salt solution produced spherical forms which, by electron microscopy and the analysis of residual cell wall material, appeared to be true protoplasts. Only undamaged mureinoplasts, as judged by their capacity to fully retain alpha-aminoisobutyric acid, were capable of being converted to protoplasts. Protoplasts and undamaged mureinoplasts retained 100% transport capacity when compared to an equal number of whole cells. The Na(+) requirement for transport of alpha-aminoisobutyric acid and the sparing action of Li(+) on this Na(+) requirement were the same for both protoplasts and whole cells. These observations indicate that, in this gram-negative bacterium, the cell wall does not participate in the transport process though it does stabilize the cytoplasmic membrane against changes in porosity produced by unbalanced salt solutions. The results also indicate that the requirements for Na(+) for transport and for the retention of intracellular solutes are manifested at the level of the cytoplasmic membrane.

Aminoisobutyric Acids↗
PubMed1979

Effect of plasma membranes on solute transport in 3T3 cells.

Sparse cultures of Swiss 3T3 cells are arrested early in the G1 phase of growth by the addition of a plasma membrane fraction obtained from confluent 3T3 cells. We have examined whether the changes in solute transport which are usually associated with cessation of growth at confluency also take place when cell growth is arrested by the addition of plasma membranes. We find that the rate of uptake of alpha-aminoisobutyric acid and uridine is decreased after the addition of plasma membranes to 3T3 cells, but the rate of uptake of 2-deoxyglucose and phosphate is not. We conclude from these observations that uptake of uridine and alpha-aminoisobutyric acid are related to contact inhibition of growth, while the decline in the rate of uptake of 2-deoxyglucose and phosphate observed at high cell density must be due to changes other than cell to cell contact.

Aminoisobutyric Acids↗
PubMed1991

Insulin-like growth factor (IGF)-binding protein-3 blocks IGF-I-induced receptor down-regulation and cell desensitization in cultured bovine fibroblasts.

Insulin-like growth factor-I (IGF-I) initiates its diverse biological effects by binding to type I IGF receptors on cells. In addition, IGF-I associates with distinct proteins that can modulate its actions. One of these IGF-binding proteins, IGFBP-3, is the major circulating form in adults and is produced by many cells in culture. We investigated the effect of purified bovine IGFBP-3 on IGF-I binding and IGF-I stimulation of amino acid uptake and DNA synthesis in cultured bovine fibroblasts, a cell culture system highly suitable for these types of studies. Incubation of cells with IGF-I resulted in time- and dose-dependent decreases in [125I]IGF-I binding and IGF-I stimulated [3H]aminoisobutyric acid uptake and [3H]thymidine incorporation. Preincubation with 4 nM IGF-I resulted in a 50-60% decrease in IGF-I receptor binding, accompanied by marked decreases in IGF-I-stimulated [3H]aminoisobutyric acid uptake (50-60%) and [3H]thymidine incorporation (80-90%). Preincubation with the IGF-I analog [QAYL]IGF-I (4 nM) or with 100 nM insulin, growth factors that bind and activate type I IGF receptor signalling but have little or no affinity for IGFBP-3, had effects comparable to IGF-I, decreasing both IGF-I binding and action 50-95%. The addition of IGFBP-3 during the preincubation period with IGF-I blocked the decrease in receptor availability and prevented the cells from becoming desensitized. IGFBP-3 did not prevent the [QAYL]IGF-I- or insulin-induced receptor loss and cellular resistance to IGF-I. These data indicate that IGFBP-3 can prevent IGF-I-induced receptor down-regulation, a process that renders cells refractory to further stimulation by IGF-I. Thus, cell-derived IGFBP-3 may function in a buffering capacity to restrict IGF-I and target cell interaction, thereby modulating the biological response to changes in local IGF-I levels.

Aminoisobutyric Acids↗
PubMed1975

Amino acid transport in placental slices. Mechanism of increased accumulation by prolonged incubation.

The accumulation of alpha-aminoisobutyric acid by placental slices is increased dramatically upon prior incubation of the slices in amino acid-free, buffered saline. This increase is inhibited by inhibitors of protein synthesis and is accompanied by an increased V for the transport process. While alternative explanations are discussed, these data suggest that the incubation effect may be mediated through an increase in the number of available transport sites which are synthesized during the incubation period. Incubation with an amino acid mixture diminishes the increase as well as general protein synthesis, suggesting that a reduced availability of amino acids may initiate compensatory changes in the synthesis of cellular transport proteins.

Amino Acids↗
PubMed1998

Three-dimensional structure of the ion-channel forming peptide trichorzianin TA VII bound to sodium dodecyl sulfate micelles.

Trichorzianin TA VII, Ac0 U1 A2 A3 U4 J5 Q6 U7 U8 U9 S10 L11 U12 P13 V14 U15 I16 Q17 Q18 Fol19, is a nonadecapeptide member of the peptaibol antibiotics biosynthesized by Trichoderma soil fungi, which is characterized by a high proportion of the alpha, alpha-dialkylated amino acids, alpha-aminoisobutyric acid (Aib, U) and isovaline (Iva, J), an acetylated N-terminus and a C-terminal phenylalaninol (Pheol, Fol). The main interest in such peptides stems from their ability to interact with phospholipid bilayers and form voltage-dependent transmembrane channels in planar lipid bilayers. In order to provide insights into the lipid-peptide interaction promoting the voltage gating, the conformational study of TA VII in the presence of perdeuterated sodium dodecyl sulfate (SDS-d25) micelles has been carried out. 1H sequential assignment have been performed with the use of two-dimensional homo- and -heteronuclear nmr techniques including double quantum filtered correlated spectroscopy, homonuclear Hartmann-Hahn, nuclear Overhauser effect spectroscopy, 1H-13C heteronuclear single quantum correlation, and heteronuclear multiple bond correlation. Conformational parameters, such as 3JNHC alpha H coupling constants, temperature coefficients of amide protons (delta gamma/delta TNH) and quantitative nuclear Overhauser enhancement data, lead to detailed structural information. Ninety-eight three-dimensional structures consistent with the nmr data were generated from 231 interproton distances six phi dihedral angle restraints, using restrained molecular dynamics and energy minimization calculations. The average rms deviation between the 98 refined structures and the energy-minimized average structure is 0.59 A for the backbone atoms. The structure of trichorzianin TA VII associated with SDS micelles, as determined by these methods, is characterized by two right-handed helical segments involving residues 1-8 and 11-19, linked by a beta-turn that leads to an angle about 90 degrees-100 degrees between the two helix axes; residues 18 and 19 at the end of the C-terminal helix exhibit multiple conformations.

Amino Acid Sequence↗
PubMed2000

Spontaneous Vesicle Formation by Helical Glycopeptides in Water.

Hydrophobic helical peptide molecules with a lactose unit at the C terminal, Nap-(Ala-Aib)(n)-NHCH(2)CH(2)NH-Lac (Nap, Aib, and Lac represent 2-naphthylacetic acid group, 2-aminoisobutyric acid, and lactobionic acid group, respectively, n=4, 6, 8), were synthesized and their formation of self-assemblies in water was investigated. Nap-(Ala-Aib)(4)-NHCH(2)CH(2)NH-Lac was spontaneously dispersed in water and formed aggregates of 70 nm diameter, shown by dynamic light scattering measurement. Cryo-TEM observation revealed that the aggregates took on a vesicular structure with a single membrane. The membrane is suggested to be composed of helical peptide molecules with an interdigitated antiparallel packing on the basis of circular dichroism and fluorescence measurements. On the other hand, the dodecapeptide formed a fibrous assembly, and the hexadecapeptide could not be dispersed in water. Copyright 2000 Academic Press.

Journal Article↗
PubMed1991

Amino acid uptake systems in lizard and chick brain cells.

The uptake of seven amino acids, alpha-aminoisobutyric acid (AIB), cyclo-leucine (cyclo-Leu), gamma-aminobutyric acid (GABA), glycine (Gly), glutamic acid (Glu), lysine (Lys), and taurine (Tau), representatives of different amino acid transport systems, was studied in slices of brain from Tokay lizards and White Leghorn chicks. In descending order, the rate of the initial uptake of the amino acids in both species was Glu greater than Gly greater than GABA greater than Cyclo-Leu greater than AIB greater than Lys greater than Tau. The substrate specificities and the differences in sodium and temperature dependence of the uptake of the amino acids indicate the presence of several distinct amino acid transport systems, some sodium-dependent and some sodium-independent. The structural specificity of amino acid transport classes in the brain of these species is similar to that in other vertebrate brain preparations.

Amino Acids↗
PubMed1988

A re-examination of the Na+-independent binding of [3H]beta-alanine to rat brain stem-spinal cord.

The Na+-independent binding of [3H]beta-alanine to rat brain stem plus spinal cord was reinvestigated, in order to study in more detail the characteristics of previously described beta-alanine binding processes. Binding was absent when amino acid-free postnuclear supernatants or crude synaptic membranes were used. Experiments performed with several other Na+-free preparations showed a sole binding component, irrespective of the preparation used. Biochemical characterization of this Na+-independent binding, using frozen/thawed/washed synaptosomal-mitochondrial fractions, showed that binding reached a plateau between 7 min and 13 min, increasing thereafter. Binding was linear with fraction protein over a range of 200-415 micrograms/ml incubation medium. Binding was completely inhibited by glycine, alanine, alpha-aminobutyric acid, beta-aminoisobutyric acid, hypotaurine and strychnine, and to a lesser extent by 2,2-dimethyl-beta-alanine, brucine and gelsemine. It was insensitive to taurine, gamma-aminobutyric acid (GABA), 2-guanidinoethanesulfonic acid (GES), carnosine, and bicuculline methiodide. Binding was reversible, saturable (KD 20 microM), and heat sensitive.

Alanine↗
PubMed1990

Toxicity of cadmium in the perfused human placenta.

Cadmium, a placental toxicant in rodents, was studied in the in vitro isolated dually perfused human placental lobule for periods of up to 12 hr to determine if cadmium can also be toxic in the human placenta. Placental lobules were perfused with a modified M199 medium containing 0, 10, 20, or 100 nmol of cadmium chloride/ml added only initially to the maternal perfusate. Every 4 hr, the perfusates in both the maternal and the fetal circuits were replaced with fresh perfusate containing no Cd. Measurements during perfusion were oxygen consumption, net fetal oxygen transfer, fetal pressure, fetal volume loss, glucose utilization, lactate production, human chorionic gonadotropin (hCG), and zinc transfer. Postperfusion, morphology, and tissue slice studies were performed to evaluate cellular metabolic function and uptake of an amino acid (alpha-[14C]-aminoisobutyric acid). In all cadmium experiments, there were no significant alterations in oxygen consumption, lactate production, glucose utilization, or amino acid uptake compared with controls; however, there were dose-related changes in the synthesis and release of the protein hormone, hCG, beginning within 4 hr of initial exposure to Cd. There were also dose-related volume loss from the fetal vasculature (greater than 6 ml/hr) and ultrastructural changes (subsyncytiotrophoblastic vesiculations, stromal edema, vacuoles in Hofbauer cells), with necrosis at 100 nmol Cd/ml occurring between 5 and 8 hr. Cadmium (10 nmol/ml) reduced the placental transfer of zinc into the fetal circuit. Thus, the human placenta is a site for toxic action of cadmium and is at least as sensitive as the rodent placenta to the actions of cadmium. In addition, these human studies demonstrated a selectivity in the toxic effects with a maintenance of carbohydrate metabolism and amino acid uptake even after 12 hr of exposure with placental Cd burdens of 151 +/- 37 nmol/g, but with the earliest (within 4 hr) dose-related functional alterations occurring in protein hormone production and zinc transfer followed by later changes in morphology with a tissue Cd burden of 46.5 +/- 4.0 nmol/g.

Amino Acids↗
PubMed1988

A computergraphic determination of the chemotactic peptide preferred conformation.

Replacement of leucine in the chemotactic peptide For-Met-Leu-Phe by the sterically constrained amino acids alpha-aminoisobutyric acid and aminocyclohexanecarboxylic acid affords compounds of equal or greater activity than the parent. NMR studies indicate that the parent compound is present as a beta-sheet in solution, whereas the analogues prefer a beta-turn. Application of molecular modelling would indicate that the beta-turn conformer is energetically preferable and thus suggests that it is the orientation adopted by the peptides.

Computer Graphics↗
PubMed1999

Transport of extraterrestrial biomolecules to the Earth: problem of thermal stability.

The idea of extraterrestrial delivery of organic matter to the early Earth is especially attractive at present and is strongly supported by the detection of a large variety of organic compounds, including amino acids and nucleobases, in carbonaceous chondrites. Whether these compounds can be delivered by other space bodies is unclear and depends primarily on capability of the biomolecules to survive high temperatures during atmospheric deceleration and impacts to the terrestrial surface. In the present study we estimated survivability of simple amino acids (alpha-aminoisobutyric acid, L-alanine, L-valine and L-leucine), purines (adenine and guanine) and pyrimidines (uracil and cytosine) under rapid heating to temperatures of 400 to 1000 degrees C under N2 or CO2 atmosphere. We have found that most of the compounds studied cannot survive the temperatures substantially higher than 700 degrees C; however at 500-600 degrees C, the recovery can be at a per cent level (or even 10%-level for adenine, uracil, alanine, and valine). Implications of the data for extraterrestrial delivery of the biomolecules are discussed.

Adenine↗
PubMed2001

Dinuclear chromium(V) amino acid complexes from the reduction of chromium(VI) in the presence of amino acid ligands: XAFS characterization of a chromium(V) amino acid complex.

The first synthesis and characterization of Cr(V) complexes of non-sulfur-containing amino acids are reported. The reduction of Cr(VI) in methanol in the presence of amino acids glycine, alanine, and 2-amino-2-methylpropanoic acid (alpha-aminoisobutyric acid, Aib) yielded several Cr(V) EPR signals. For the reaction involving glycine, the only Cr(V) EPR signals detected were those of the Cr(V)-intermediate methanol complexes, which were also observed in the absence of amino acids. The reaction involving alanine yielded one Cr(V) signal with a g(iso) value of 1.9754 (a(iso) = 4.88 x 10(-4) cm(-1) and A(iso)(53Cr) = 17.89 x 10(-4) cm(-1)). However, a solid product isolated from the reaction solution was EPR silent and was characterized as a dioxo-bridged dimeric species, [Cr(V)2(mu-O)2(O)2(Ala)2(OCH3)2](2-), by multiple-scattering XAFS analysis and electrospray mass spectrometry. The EPR spectrum of the reduction reaction of Cr(VI) in the presence of Aib showed several different Cr(V) signals. Those observed at lower g(iso) values (1.9765, 1.9806) were assigned to Cr(V)-methanol intermediates, while the relatively broad six-line signal at g(iso) = 2.0058 was assigned as being due to a Cr(V) complex with coupling to a single deprotonated amine group of the amino acid. This was confirmed by simplification of the superhyperfine coupling lines from six to three when the deuterated ligand was substituted in the reaction. The reduction of Cr(VI) with excess alanine or Aib ligands resulted in the formation of tris-chelate Cr(III) complexes, which were analytically identical to complexes formed via Cr(III) synthesis methods. The fac-[Cr(Aib)3] complex was characterized by single-crystal X-ray diffraction.

Amino Acids↗
PubMed2002

Reactivity of amino acids in nitrosation reactions and its relation to the alkylating potential of their products.

Nitrosation reactions of amino acids with an -NH(2) group [namely, six alpha-amino acids (glycine, alanine, alpha-aminobutyric acid, alpha-aminoisobutyric acid, valine, and norvaline); two beta-amino acids (beta-alanine and beta-aminobutyric acid), and one gamma-amino acid (gamma-aminobutyric acid)] were studied. Nitrosation was carried out in aqueous acid media, mimicking the conditions of the stomach lumen. The rate equation was r = k(3)(exp)[amino acid][nitrite](2), with a maximum k(3)(exp) value in the 2.3-2.7 pH range. The existence of an isokinetic relationship supports the argument that all the reactions share a common mechanism. A nitrosation mechanism is proposed, and the following conclusions are drawn: (i) Nitrosation reactions of amino acids with a primary amino group in acid media occur with dinitrogen trioxide as the main nitrosating agent. The finding that the nitrosation rate is proportional to the square of the nitrite concentration suggests that the yield of nitrosation products in the stomach would increase sharply with higher nitrate/nitrite intakes. (ii) Stomach hypochlorhydria could be a potential enhancer of in vivo amino acid nitrosation. (iii) The reactivity (k(3)()(exp)) [alpha-amino acids > beta-amino acids > gamma-amino acids] is the same as that found in a previous work for the alkylating potential of lactones formed from nitrosation products of the same amino acids. This implies that the nitrosation reactions of the most common natural amino acids are the most efficient precursors of the most powerful alkylating agents. (iv) The order of magnitude (10(7)-10(8) M(-1) s(-1)) of the bimolecular rate constants of nitrosation shows that such reactions occur through an encounter process.

Alkylating Agents↗
PubMed2006

Molecular definition of the taste of roasted cocoa nibs (Theobroma cacao) by means of quantitative studies and sensory experiments.

Sensory-guided decomposition of roasted cocoa nibs revealed that, besides theobromine and caffeine, a series of bitter-tasting 2,5-diketopiperazines and flavan-3-ols were the key inducers of the bitter taste as well as the astringent mouthfeel imparted upon consumption of roasted cocoa. In addition, a number of polyphenol glycopyranosides as well as a series of N-phenylpropenoyl-l-amino acids have been identified as key astringent compounds of roasted cocoa. In the present investigation, a total of 84 putative taste compounds were quantified in roasted cocoa beans and then rated for the taste contribution on the basis of dose-over-threshold (DoT) factors to bridge the gap between pure structural chemistry and human taste perception. To verify these quantitative results, an aqueous taste reconstitute was prepared by blending aqueous solutions of the individual taste compounds in their "natural" concentrations. Sensory analyses revealed that the taste profile of this artificial cocktail was very close to the taste profile of an aqueous suspension of roasted cocoa nibs. To further narrow down the number of key taste compounds, finally, taste omission experiments and human dose/response functions were performed, demonstrating that the bitter-tasting alkaloids theobromine and caffeine, seven bitter-tasting diketopiperazines, seven bitter- and astringent-tasting flavan-3-ols, six puckering astringent N-phenylpropenoyl-l-amino acids, four velvety astringent flavonol glycosides, gamma-aminobutyric acid, beta-aminoisobutyric acid, and six organic acids are the key organoleptics of the roasted cocoa nibs.

Cacao↗
PubMed1999

Transport of pregabalin in rat intestine and Caco-2 monolayers.

PURPOSE: The purpose of this study was to determine if the intestinal transport of pregabalin (isobutyl gamma-aminobutyric acid, isobutyl GABA), a new anticonvulsant drug, was mediated by amino acid carriers with affinity for large neutral amino acids (LNAA). METHODS: Pregabalin transport was studied in rat intestine and Caco-2 monolayers. An in vitro Ussing/diffusion chamber model and an in situ single-pass perfusion model were used to study rat intestinal transport. An in vitro diffusion chamber model was used to evaluate Caco-2 transport. RESULTS: In rat ileum, pregabalin transport was saturable and inhibited by substrates of intestinal LNAA carriers including neurontin (gabapentin), phenylalanine, and proline. Weak substrates of intestinal LNAA carriers (beta-alanine, gamma-aminobutyric acid, and methyl aminoisobutyric acid) did not significantly change pregabalin transport. In Caco-2 monolayers that showed a high capacity for phenylalanine transport, pregabalin transport was concentration- and direction-independent and equivalent in magnitude to the paracellular marker, mannitol. The in vitro and in situ rat ileal permeabilities of the LNAA carrier-mediated compounds neurontin, pregabalin, and phenylalanine correlated well with the corresponding in vivo human oral absorption. CONCLUSIONS: The transport of pregabalin was mediated by LNAA carriers in rat ileum but not in Caco-2 monolayers. Caco-2 was not an appropriate model for evaluating the in vivo human oral absorption of pregabalin and neurontin.

Acetates↗
PubMed1987

Topography of capillary density, glucose metabolism, and microvascular function within the rat inferior colliculus.

A midbrain nucleus of the auditory system, the inferior colliculus, was used as a model for analyzing spatial correlations or "coupling" among capillary density, tissue glucose metabolism, and several measures of microvascular function in the rat. The capillary bed of the inferior colliculus was examined with stereological techniques, and physiological measures were obtained with radioactive tracers, quantitative autoradiography, and image processing. Within the colliculus, capillary density, volume fraction, length, and surface area were highest in the central nucleus where the packing densities of neuropil and perikarya are greatest. Rates of glucose metabolism and blood flow correlated closely with capillary density in a 3 X 2 matrix of collicular subregions in the sagittal and coronal planes. The strength of this correlation suggests that estimates of capillary density can be made from measurements of tissue glucose metabolism within this structure under normal conditions. Microvascular blood volume and transcapillary flux of a neutral amino acid, alpha-aminoisobutyric acid, were homogeneous throughout the colliculus. The studies demonstrate quantitatively in a single brain nucleus a close correspondence between cytoarchitecture, richness of the capillary bed, and complexity of neural activity (inferred from local measures of glucose metabolism and blood flow). Such relationships were suggested by Craigie 67 years ago.

Animals↗