Slices of mammalian brain accumulate H(3)-norepinephrine and H(3)-serotonin when incubated in a physiologic medium containing these tritiated monoamines. When these tissues are subjected to mild electrical stimulation of short duration, which is associated with depolarization of nerve membranes, a striking increase in the rate of efflux of the exogenous labeled monoamines occurs. Stimulation-induced release of both labeled monoamines is diminished by the presence of lithium ions in the perfusing medium; related monovalent cations had no such effect. Evoked release from slices of brain from animals treated intraperitoneally with lithium chloride for 3 days was also reduced.
Electroencephalograms (EEGs) of a cohort of 52 septuagenarians rigorously selected for neuropsychiatric "normalcy" were examined, with attention to alpha frequency and focal or diffuse slowing. Contrary to the widely accepted notion of diminution in these EEG signs in patients of this age group, the findings of this study revealed alpha frequencies approximating 10 Hz and no focal or diffuse slowing. These results are discussed in relation to clinical EEG interpretation as well as to the aging process.Over the past 40 years, relatively few comprehensive electroencephalographic (EEG) studies of the asymptomatic aged adult have been published. In normal geriatric populations, the reported EEG changes have included slowing of dominant rhythmic posterior activity, alterations in lowvoltage fast rhythms, and diffuse as well as focal slowing, the latter most often over the temporal regions.l-B The extent of correlation between the EEG differences and variables in mental and physical function as well as the underlying pathologic changes remains to be defined. A critical methodologic problem has been the varying composition of the populations studied, the sampling techniques, and the definition of appropriate control groups.
Torulopsis utilis yeast cells growing exponentially on synthetic medium with ethanol as carbon and energy source are insensitive to rotenone; the cells acquire the rotenone-sensitive component of the mitochondria1 electron transport chain upon entering an ethanol-depleted stationary phase. The rotenone-sensitive site is lost when growth is restimulated with ethanol, but not when growth is restimulated with glycerol or acetic acid. Growth limitation by iron or by glucose or glycerol is also characterized by acquisition of the rotenone-sensitive site, upon entering stationary phase. The transition from rotenone-sensitive to -insensitive can also be studied by the use of semicontinuous culture in a chemostat. Studies with the protein synthesis inhibitors cycloheximide and chloramphenicol indicate that protein synthesis on cytoplasmic ribosomes is required both for the acquisition and the loss of the rotenone-sensitive site. The acquisition of rotenone sensitivity is apparently associated with an increased phosphorylation efficiency, as evidenced by measurements of P/O ratios.I n a previous paper [l], it was reported that Torulopsis utilis yeast cells harvested from an exponentially growing culture are insensitive to rotenone and Piericidin A, inhibitors of mitochondrial electron transport. However, respiration of cells harvested from a culture which has reached stationary phase due to depletion of ethanol (the carbon source used in the experiments reported) and has been in this starved state for approximately 15 min, is cut 60°/0 to 80°/, by rotenone. It was also reported that if additional substrate (ethanol) is administered to the starved stationary culture, rotenone sensitivity is lost within 15min. In this communication we present some further data on the property of rotenone sensitivity in Torulopsis utilis, seeking to explain the sort of transition that takes place when a culture of rotenone-insensitive yeast cells exhaust their carbon source and enter stationary phase, thus acquiring the rotenone-sensitive component of the electron transport chain.
MATERIALS AND METHODSThe techniques used for culturing T . utilis were as described previously [l]. Rotenone sensitivity was assayed as in [l]. Yeast mitochondria were prepared there was a nearly linear drop in pH and the rate of culture oxygen consumption increased exponentially. Oxygen consumption of samples of intact cells removed from the culture during this time (from zero time to 6 h) was not inhibited by rotenone even a t concentrations of 5 mM. Shortly before growth ceased due to depletion of ethanol the respiratory rate of the culture fell, followed by a last burst of oxygen consumption, and acid secretion stopped. Midway through this final burst of respiration, the first cells appeared which were partially inhibited by rotenone. This sensitivity to rotenone increased to approximately 50 Ol0 with subsequent aliquots. The culture was kept in this carbon-starved state for approximately 3 h. At this point, cycloheximide was added at a final concentration of...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.