Benzodiazepine receptor binding in vivo with [3H]-Ro 15-1788

In vivo benzodiazepine receptor binding has generally been studied by "ex vivo" techniques. In this investigation, we identify the conditions where [3H]-Ro 15-1788 labels benzodiazepine receptors by true "in vivo" binding, i.e. where workable specific to nonspecific ratios are obtained in intact tissues without homogenization or washing. [3H]-Flunitrazepam and [3H]-clonazepam did not exhibit useful in vivo receptor binding.     

The subcellular distribution of endogenous and exogenous serotonin in brain tissue: comparison of synaptosomes storing serotonin, norepinephrine, and gamma-aminobutyric acid

Abstract— We have studied the subcellular distribution of exogenous and endogenous serotinin in slices from the hypothalamus and midbrain of several species. In a procedure which appears to label the endogenous pools, tissue slices were incubated with low concentrations of [³H]5-HT (5 × 10^-8 M), for 45 min, when there was apparent equilibrium between [³H]5-HT of tissue and medium. After the tissue slices were homogenized in 0-32 M-sucrose and subjected to differential centrifugation, the distribution of exogenous and endogenous 5-HT in pellets and supernatant fluid was similar. In some experiments, the crude mitochondrial pellets were resuspended in 0-32 M-sucrose, layered on linear, continuous density gradients of sucrose (1 -5-0-32 M), and centrifuged for short times (incomplete equilibrium centrifugation). The subcellular distribution of particulate tritium, total tritium, and particulate endogenous 5-HT was the same in portions of the gradients containing synaptosomes. The peak distribution of [³H]5-HT in sucrose gradients was separable from the peak for [¹⁴C]GABA by four to five fractions; potassium (a marker for cytoplasm occluded within synaptosomes) occurred in the regions of the gradients containing most of the labelled compounds. The distribution of monoamine oxidase activity (a mitochondrial marker) overlapped the distribution of [³H]5-HT after a 15 min centrifugation but appeared in denser regions of the gradient after centrifuging for 2 h. Particles containing [3H]5-HT and [I4C]NE were slightly but consistently separable in synaptosomal fractions isolated from the hypothalamus or midbrain of rat, guinea pig and hamster.     

Seed transmission of turnip yellow mosaic virus in winter turnip and winter oilseed rapes

This is the first record of seed transmission of turnip yellow mosaic virus (TYMV) in oilseed and turnip rapes. The seed transmission of TYMV in a naturally infected winter turnip rape (Brassica napus var. silvestris) cultivar Perko PVH was investigated. By ELISA 1.6%, 3.2% and 8.3% seed transmission of the virus was found in seed of plants from three localities. The proportion of infected seeds produced by artificially infected plants of winter oilseed rape (Brassica napus ssp. oleifera) and winter turnip rape cultivars was determined. The virus transmission rate, expressed as the proportion of virus-infected plants which germinated from the seed was for the oilseed rape cvs Jet Neuf 0.1%, Solida 0.4%, Silesia 0.8%, Darmor 1.2%, SL-507 0.2%, SL-509 0.0% and for the winter turnip rape cv. Perko 1.5%. ELISA cannot be used in direct tests on bulk seed lots to estimate proportion of infected seed, but must be used on germinated seedlings.     

Aspects of hadrosaurian cranial anatomy

Supraorbital bones in Saurolophus angustirostris are described, and their presence in all hadrosaurs is suggested. Frontal-nasal and premaxillar-nasal fontanellae are distinguished in hadrosaurs; their presence is explained as connected with growth and considered to he responsible for the variability of crest structures. New data indicating the presence of a cartilaginous diverticulum nasi within the circumnarial depression in Saurobphus ongustirostris are presented. A physiological (respiratory and/or thermoregulatory) function of the nasal diverticulum is proposed.     

BINDING OF [3H]KAINIC ACID, AN ANALOGUE OF l-GLUTAMATE, TO BRAIN MEMBRANES

—The specific binding of [³H]kainic acid to synaptic membranes from rat brain was saturable with a dissociation constant of about 60 nm . The apparent maximal number of binding sites was about 1 pmol/mg protein. The most effective displacer of specific [³H]kainic acid binding was quisqualic acid, a powerful excitant which is structurally similar to l -glutamate. However, quisqualic acid was one-third as potent a displacer as kainic acid itself. l -Glutamate was the next potent in displacing [³H]kainic acid binding, but also was less effective (1/25) than kainic acid itself. All other compounds including suspected neurotransmitters were at least an order of magnitude lower in potency compared to l -glutamate. When various tissues and brain regions were tested for specific [³H]kainic acid binding, we found the specified binding was localized to grey matter in the brain. In studies of subcellular fractionation of the brain, we found that crude synaptosomal membrane preparations were most enriched in specific [³H]kainic acid binding. Specific [³H]kainic acid binding in various regions of the rat brain varied 5- to 6-fold.     

HIGH AFFINITY CHOLINE UPTAKE: IONIC AND ENERGY REQUIREMENTS

Abstract— High affinity choline uptake into rat hippocampal synaptosomes was examined at 37°C when various ions were deleted from normal Kreb's-Ringer media. When sodium chloride was replaced by sucrose, lithium chloride, cesium chloride or rubidium chloride, choline uptake was markedly reduced. When the sodium concentrations of the Kreb's media were gradually reduced to zero, the uptake was gradually reduced in parallel. A kinetic analysis performed at low and normal sodium concentrations revealed changes in K_m and V^max values. When several non-chloride sodium salts were utilized, the uptake was reduced in all cases suggesting also a chloride-dependence in addition to the sodium-dependence. Omission of calcium chloride or magnesium sulfate from the media did not alter uptake. Sodium-dependent choline uptake was examined over a range of potassium concentrations (0–35 DIM). It was found that uptake was maximal between potassium concentrations of 0.35–4.8 mm but was reduced at both lower and higher potassium concentrations. The kinetics of uptake were examined under varying potassium concentrations, and at low potassium, only a change in V_max was observed while at high potassium concentrations, there were changes in both K^m and V^max values. Preincubation and incubation of synaptosomes with 0.1 m -ouabain, 0.1 mm -2,4-dinitrophenol and 1 mm -KCN caused a reduction in sodium-dependent uptake. When dextrose was omitted from the preincubation and incubation media there was also a reduction in sodium-dependent uptake. By contrast, the sodium-independent uptake was unaffected by the metabolic inhibitors or omission of dextrose, and had a very low Q₁₀. When various incubation temperatures were utilized in uptake experiments, the Q¹⁰ for the interval 37-27°C was 2.7 and the activation energy was 22.7 kcal/mol. Slightly different ionic dependences were observed when animals pretreated with pentobarbital of oentylenetetrazol were utilized as the source of synaptosomes.     

European checkerspots (Melitaeini: Lepidoptera,Nymphalidae) are not aposematic – the point of view of great tits (Parus major)

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Multiplex panels of polymorphic microsatellite loci for two cryptic bat species of the genus Pipistrellus,developed by cross‐species amplification within the family Vespertilionidae

The paper presents multiplex panels of polymorphic microsatellites for two closely related cryptic species Pipistrellus pipistrellus and Pipistrellus pygmaeus. We tested the cross‐species amplification of 34 microsatellite loci, originally developed for five vespertilionid bat species. Ten and nine polymorphic loci in P. pipistrellus (mean number of alleles per locus = 10.5) and P. pygmaeus (8.1), respectively, in three multiplex polymerase chain reactions per species were amplified. All loci can be analysed in a single fragment analysis and can be used as markers to the study of evolution and the ecology of structured populations of socially living bats.