Carbachol and gamma-aminobutyric acid depolarize mammalian sympathetic neurons and increase the free extracellular K+-concentration. We have used double-barrelled ion-sensitive microelectrodes to determine changes of the membrane potential and of the free intracellular Na+-, K+- and Cl- -concentrations ( [Na+]i, [K+]i and [Cl-]i) during neurotransmitter… (More)
A post-tetanic membrane hyperpolarization following repetitive neuronal activity is a commonly observed phenomenon in the isolated frog spinal cord as well as in neurons of other nervous tissues. We have now used double-barrelled Na+- and K+-ion-sensitive microelectrodes to measure the intracellular Na+- and K+-concentrations and also the extracellular… (More)
Three different regions of the vertebrate central nervous system maintained in vitro (frog spinal cord, guinea pig olfactory cortex and hippocampus) have been used to investigate how Li+ influences membrane potential, membrane resistance, action potentials, synaptic potentials and the transmembrane K+-distribution of neurons and glial cells. In view of the… (More)
Lithium sensitive microelectrodes were used to investigate the transmembrane distribution of lithium ions (Li+) in motoneurons of the isolated frog spinal cord. After addition of 5 mmol.1(-1) LiCl to the bathing solution the extracellular diffusion of Li+ was measured. At a depth of 500 micrometers, about 60 min elapsed before the extracellular Li+… (More)
A chemical budget analysis for Williams Lake, Minnesota, tracks the seasonal progression of carbon inputs and outputs. CO, exchanges with the atmosphere reverse seasonally, with uptake by the lake in summer preceded and followed by larger losses to the atmosphere. Calcium bicarbonate-rich groundwaters seep steadily into the lake, augmented by remobilization… (More)
As we have drawn the year 2013 to a close, we would like to take a moment to sum up the number of technological communications that AMRI scientists have contributed to the scientific community during this year. Please read through this document for a full list of the graphical abstracts as they appeared in the journal in which they were published. Earlier… (More)
Our previous research has demonstrated that dissolved organic matter (DOM) influences calcium carbonate mineral formation in surface and ground water. To better understand DOM mediation of carbonate precipitation and DOM co-precipitation and/or incorporation with carbonate minerals, we characterized the content and speciation of DOM in carbonate minerals… (More)
Cover Picture Icy Shore-a painting meant to subtly convey the menace of the 80-90% of an iceberg that lies below the ocean surface.
Susitna Glacier, Alaska—a " textbook example " of folded moraines caused by repeated surges. Glacier surges not only are extremely rapid transformations of glacier flow and geometry but also provide vital clues to the basal sliding mechanism of glacier flow.
The subalpine plant kinnikinnik (Arctostaphylos uva-ursi) growing by a log. Photo by Tad Pfeffer.