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The vasoconstrictor responses of isolated rat portal vein and aorta to synthetically prepared endothelin are investigated. Both preparations respond to 10(-9) M levels of the peptide although the aortic response is more sustained than that of the portal vein. Endothelin-evoked contractions, unlike those evoked by scorpion alpha-toxins (which are homologous(More)
The effects of endothelin, a potent endogenous vasoconstrictor peptide, were examined in a range of vascular and non-vascular tissues. At concentrations that cause vasoconstriction in portal vein and aorta, the peptide strongly contracted rat uterus, trachea and vas deferens, but not guinea pig ileum. Nifedipine, a dihydropyridine calcium anatgonist,(More)
Potato tubers (Solanum tuberosum L. cv. Binje) were stored at 18 and 4oC in order to verify changes in mitochondrial metabolism, especially in the activities of the alternative oxidase (AOX) and plant uncoupling mitochondria protein (PUMP). Tubers were also sliced and submitted to artificial aging. The oxygen consumption rate (OCR), respiratory control (RC)(More)
The extracellular fluid phase marker, horseradish peroxidase, enters chromaffin cells when triggered to secrete catecholamine. This triggered uptake, like secretion, is abolished in cells pre-incubated with botulinum toxin. Endocytosis of horseradish peroxidase into unstimulated cells is unaffected by botulinum toxin but is inhibited when the temperature is(More)
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