Gamma-aminobutyric acid uptake by rat kidney brush-border membrane vesicles

Summary Brush-border membrane vesicles (BBMV) from rat kidney cortex possessed two uptake systems for -aminobutyric acid (GABA), a high affinity system (Km=10.9 M) and a low affinity system (Km=1203 M). Both uptake systems were inhibited by p-hydroxymercuribenzoic acid and ouabain, and by the action of neuraminidase, whereas the GABA analogs nipecotic acid, -alanine, 2,4-diaminobutyric acid and 4,5,6,7-tetrahydroisoxazolo-[4,5c]-pyridin-3-ol had no effect on the GABA uptake activity. The BBMW uptake systems were clearly different from the GABA transport systems present in brain tissue.     

Hemagglutination of neuraminidase-treated human erythrocytes byLeishmania enriettii infected guinea-pig sera

Summary Sera from guinea-pigs infected with the protozoan parasiteLeishmania enriettii showed higher hemagglutination (HA) titres for neuraminidase treated human erythrocytes than those of normal guinea-pig sera. This HA activity was associated mostly with the 19S fraction of the immune serum and could be absorbed out with an antigenic fraction of the parasite membrane. Antigenic determinants involved in this HA reaction consisted of, at least, -d-galactosyl or lactosyl residues.     

Regional pattern and heat-resistance of brain 5′-deoxy-5′-methylthioadenosine phosphorylase

Summary The distribution of 5-deoxy-5-methylthioadenosine (MTA) phosphorylase in 10 pig brain areas was determined. The observed regional differences of the enzymatic activity seem to reflect more the pattern of brain spermine distribution rather than that of spermidine. Moreover, comparative studies on the heat-resistance of MTA phosphorylase extracted from the whole brain of various species suggest structural differences in the enzyme molecules occurring in the brains of different animals.     

Evaluation of monoaminergic receptors in the genetically epilepsy prone rat

Summary The intensity of sound-induced convulsions in the genetically epilepsy-prone rat (GEPR) was reduced in a dose related fashion by intracerebroventricular administration of dobutamine, (₁ agonist), terbutaline (₂ agonist) or phenylephrine (₁ agonist). BHT-920 (₂ agonist) did not cause a dose-related decrease in sound-induced convulsion intensity. Binding studies showed that whole brain and receptor densities (B_max) were normal while the K_d was increased for the ligand in GEPR brain.Acknowledgment. We are most grateful to Boehringer Ingelheim for generously supplying BHT 920. We are also indebted to Ciba-Geigy Corporation for the gift of terbutaline hydrochloride and phentolamine hydrochloride. The work was supported in part by NIH grant NS 16829.     

Intraspezifische Unterschiede der relativen Hirngrösse beim Löwen (Panthera leo L.)

Summary Different stages of brain evolution expressed by the allometric relation of³ brain capacity and basal length of the skull are shown to be existent in the speciesPanthera leo. Whereas Asiatic lions obviously have the same level of brain size as leopards (Panthera pardus), African lions have higher brain capacities. A third level seems to be represented by the upper pleistocene American lion,Panthera leo atrox. These results permit us to reject some conceptions ofHerre andRöhrs ¹³ concerning the quantitative expression of mammalian brain evolution.     

Partial purification and characterization of acid phosphatase from sporulated oocysts ofEimeria tenella

Summary Acid phosphatase ofEimeria tenella oocysts (Peak II) was purified 77-fold with a recovery of 26% using protamine sulfate precipitation, DEAE-cellulose chromatography and Sephadex G-200 gel filtration. This enzyme occurs in multiple forms as indicated by two peaks which can be separated by DEAE-cellulose chromatography and polyacrylamide gel electrophoresis. The partially purified enzyme has optimal activity at pH 4.5. With p-nitrophenyl phosphate the Km and V_max values for (Peak II) were 25 mM and 1.57 mol/min/mg protein, respectively. The enzyme (Peak II) ist strongly inhibited by Hg⁺⁺, Cu⁺⁺, iodoacetamide, fluoride and molybdate. Tartrate and other divalent metal ions have no effect on enzyme activity. The partially purified Peak II phosphatase is not a glycoprotein as it is not absorbed on concanavalin-A Sepharose and its treatment with bacterial neuraminidase does not alter its elution profile through DEAE cellulose.     

Reserpin und γ-Aminobuttersäuregehalt des Gehirns

Summary 1. In mice,reserpine (5 mg/kg) causes a long-lasting depletion of the brain for -aminobutyric acid (GABA), which corresponds temporally to the lowered seizure threshold (electroshock).2.Iproniazid prohibits both the depletion of GABA and the lowering of seizure threshold.3. Relations between amine- and GABA-metabolism of the brain are pointed out.     

Missense mutations resulting in type 1 lissencephaly

Proper human brain formation is dependent upon the integrated activity of multiple genes. Malfunctioning of key proteins results in brain developmental abnormalities. Mutation(s) in the LIS1 gene or the X-linked gene doublecortin (DCX) results in a spectrum of disorders including lissencephaly, or smooth brain, and subcortical band heterotopia, or doublecortex. Here, we will focus on a particular subset of missense mutations in these two genes and their effect on protein structure and function.Received 4 August 2004; received after revision 26 September 2004; accepted 5 October 2004     

Poly(A) associated RNA from mitochondria and microsomes of rat brain

Summary Rat brain mitochondria contain a significant proportion of poly(A) associated RNA which is higher than that found in microsomes from the same source. When steady state poly(A) RNA of brain mitochondria was analyzed by microelectrophoresis, it displayed a characteristic separation pattern with a large amount of free poly(A).     

Multiplicity of monoamine oxidase in chick brain

Summary The substrate- and inhibitor-related characteristics of monoamine oxidase (MAO) were studied on chick brain mitochondria. It was found that neither 5-hydroxytryptamine nor -phenylethylamine is the specific substrate for type A and type B MAO in chick brain.     

High-affinity binding ofβ-alanine to cerebral synaptosomes might involve glycine-receptors

Summary High-affinity, Na⁺-independent binding of -alanine to a synaptosomal fraction of rat brain was potently inhibited by glycine and by some other -amino acids, but not by taurine or GABA. This binding mechanism, which was also sensitive to both bicuculline and strychnine, might involve synaptic receptors for both -alanine and glycine.This study was supported in part by Centro Ramón y Cajal and Fundacion Juan March.     

Zur Histochemie der Gliafaser

Summary Histochemical investigations (periodate-Schiff reaction, lead-tetra-acetate-Schiff reaction, chromic acid-Schiff reaction, acetylation-, deacetylation-, and bromination-test) of neuroglial fibres from human brain and spinal cord indicate, that these proteinic fibres contain a small amount of prosthetic carbohydrate. The weak periodate reactivity of the glial fibres is due to -glycol groups and not to -oxy-amino-acids.     

Maternal vitamin A restriction alters biochemical development of the brain in rats

Summary The biochemical development of the fetal brain in relation to maternal vitamin A restriction was studied in rats. The vitamin A status of pregnant rats was varied by supplying low, medium and adequate amounts (6, 40, and 100 g retinol/day/kg body weight, respectively) of vitamin A during pregnancy and suckling. The maternal vitamin A restriction caused an altered brain development in terms of tissue weight, DNA, RNA and protein levels, and biosynthesis of DNA and protein from [³H]-thymidine and [³H]-leucine, respectively. A dose-dependent effect of maternal vitamin A restriction on the metabolism of DNA, RNA and protein was noticed in the developing fetal brain of rats.     

α-L-aspartyl-L-alanine (a neural dipeptide) enhances synaptic transmission

Summary -L-aspartyl-L-alanine, a dipeptide found in the brain, increases the amplitude of the miniature endplate potentials (MEPPs) in phrenic nerve-diaphragm preparations from rats. The peptide also stimulates the appearance of a population of giant MEPPs.This work was supported by NSF grant BNS 79-00352 and NIH grant CA-27031 to R. Lim.     

Cysteine-induced effect on amino acids in neonatal rat brain

Summary In neonatal rat brain 6 h after s.c. administration of L-cysteine, an increase was observed in most of the amino acids with the exception of glutamic acid, aspartic acid, phenylalanine, sarcosine, glutamine, hydroxyproline and phosphoethanolamine compared to age-matched saline controls. Cysteine was not present at detectable levels in control brain but was found to be 0.38 to 0.52 mole/g of fresh brain tissue in 2- and 4-day-old rats respectively after cysteine treatment.     

‘Binding’ of glutamate and aspartate to synaptosomal fractions of six regions of the feline brain

The order of potency of binding of both glutamate and aspartate to synaptosomal fractions of brain regions was: cerebellar cortex caudate nucleus cerebral cortex > medulla pons > corona radiata. Glutamate was bound to a greater extent than aspartate to particles of all regions studied, except for cerebral cortex.     

Autoradiographic localization of the uptake of3H-β-alanine in rat nervous tissue cultures

Summary Autoradiographic studies on the uptake of³H--alanine have shown that, in spinal cord and brain stem cultures, both neurones and glial cells have accumulated the amino acid. In contrast, in cultures of cerebellum and dorsal root ganglia,³H--alanine was only taken up by glial elements.     

Localisation par immunofluorescence de peptides analogues à l'α-endorphine dans les ganglions infra-œsophagiens du lombricideDendrobaena subrubicunda Eisen

Summary Using an -endorphin antiserum in brain and infra-sophageal ganglions ofDendrobaena (Lumbricidae), positive immunoreaction was found in 4 cells of the infra-oesophageal ganglions: a pair of conic perikarya in the anterior region and a pair of pear-shaped elements close to the origin of the last nerve of the ganglion. No reaction was observed with -endorphin, or neurophysin or vasopressin antisera.     

Evidence for suppression of Na-dependent Ca2+ efflux from rat brain synaptosomes by ovarian steroids in vivo

Summary The possibility that intracellular Ca²⁺, which mediates neurotransmitter release, regulation of membrane permeability, microtubule polymerization and axonal transport, is influenced by gonadal steroids via a Na–Ca exchange mechanism was examined. The resting Ca²⁺ uptake into synaptosomes was measured using crude synaptosomal pellets (P₂ fraction), isolated from the brain stem, mesencephalic reticular formation (MRF), nucleus caudatus (NC) and the hippocampus of intact, long-term ovariectomized (OVX) and OVX plus progesterone (P) or estradiol-17 benzoate (EB) treated adult female rats. Irrespective of the brain structure investigated, the uptake was 1) markedly increased in synaptosomes from OVX animals in comparison to intact controls, and 2) reduced to near control values in synaptosomes from OVX rats treated s.c. with a single dose of 2 mg P or 5 g EB. Since Ca²⁺ influx into synaptosomes was shown earlier to depend on external sodium concentration, which was the same in all experiments described in this work, the results obtained indicate that ovarian steroids modulate basal synaptic activity in the rat brain by suppressing Na-dependent Ca²⁺ efflux from the nerve cell.