D K Bartschat

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86Rb efflux from pinched-off rat brain presynaptic nerve terminals (synaptosomes) was used to measure the K permeability of the terminals. Synaptosomes were pre-loaded with 86Rb and the suspensions were then filtered on glass fibre filters. The terminals trapped on the filters were superfused with 'efflux solutions', and the effluent and filters were then(More)
Phencylidine (PCP) is a major drug of abuse in the United States. It produces a toxic confusional psychosis in man. We show here that nanomolar to micromolar concentrations of PCP and behaviorally active congeners selectively block voltage-regulated noninactivating (or very slowly inactivating) presynaptic K channels in the brain. The rank order of potency(More)
86Rb efflux was examined in isolated presynaptic nerve terminals (synaptosomes) from rat brain in a study designed to assess K permeability (PK) changes sensitive to alterations in internal Ca activity. Rb efflux from 86Rb-loaded synaptosomes into nominally Ca-free physiological saline (PSS) containing 5 mM-K was about 0.3-0.4%/s. Raising extracellular K(More)
Nerve terminals ("synaptosomes") isolated from rat brain hippocampus were loaded with the fluorescent Ca2+ indicator fura-2 and were subjected to depolarization with an elevated K+ concentration in a stopped-flow spectrophotometer to measure the activity of voltage-gated Ca2+ channels in the presynaptic membrane. Three components of Ca2+ influx were seen,(More)
Calcium uptake by vesicles in a highly enriched sarcolemma preparation from canine ventricle was found to be markedly stimulated by intravesicular calcium. Stimulation of calcium uptake appeared to be a saturable function of intravesicular calcium. Calcium efflux from the vesicles was stimulated by calcium in the reaction medium. Calcium uptake, supported(More)
1. Efflux of 86Rb from synaptosomes prepared from rat forebrain was used to assess voltage-gated changes in K+ permeability in mammalian central nerve terminals. 2. Although they are structurally unrelated to phencyclidine (PCP), the sigma-ligands, N-allyl-normetazocine (NANM; SKF 10,047) and cyclazocine, generalize to PCP in behavioral assays, displace(More)
Learning und memory in Dro-sophila, studied with mutants. Interaction of eye protein kinase C and INAD in Drosophila. Localization of binding domains and electrophysio-logical characterization of a loss of association in transgenic flies. Comparative study of the antennal lobes and their afferent pathway in the worker bee and drone. Spatially resolved(More)
1. Changes of cytoplasmic free calcium levels ([Ca2+]i) in isolated rat brain nerve terminals (synaptosomes), previously loaded with the fluorescent intracellular calcium indicator Fura-2, were measured 1-2 ms after depolarization with elevated K+ by stopped-flow fluorescence spectroscopy. 2. In physiological saline (PSS) containing 4 mM-K+, intraterminal(More)
Experiments were carried out to test the hypothesis that membrane depolarization stimulates Ca2+ uptake by vesicles in a sarcolemma preparation. Vesicles from a highly enriched sarcolemma preparation, previously loaded with 150 mM K+, developed a membrane potential when placed in a medium with 2.5 mM K+ as confirmed by changes in fluorescent intensity of(More)
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