No abstract

Mice were given a single training trial and then received either sham treatment or electroconvulsive shock (ECS; four treatments at hourly intervals) at 1 of 7 times (1-70 days) after training. Retention was always tested 2 weeks after treatment. Control animals exhibited gradual forgetting with increasing retention intervals. Mice given ECS exhibited severe retrograde amnesia, which diminished as the interval between training and ECS increased from 1 to 21 days. ECS given 21-70 days after training had no effect on memory. The finding of long, temporally graded retrograde amnesia in mice establishes continuity between the results for laboratory animals and those for humans and indicates that the neural changes involved in the consolidation of memory can continue for a significant portion of the lifetime of a memory.

The sleep-wakefulness pattern and brain protein levels were determined in rats for 3 h following these conditions: administration of an inhibitor of protein synthesis (anisomycin), administration of several doses of rat growth hormone (GH) or thyrotropin, and administration of a combination of anisomycin + GH or thyrotropin. Anisomycin inhibited sleep and increased wakefulness, GH increased REM sleep, and thyrotropin produced no change. The combined administration of GH and anisomycin returned sleep to control levels. Anisomycin produced a time-dependent decrease in brain protein levels, GH produced changes in brain protein levels as compared to controls in the second hour only, and thyrotropin had no effect upon brain protein levels. The results are discussed in terms of the possible relationship between sleep and proteins.

Rates of photosynthesis, measured by oxygen electrode or by (14)CO(2) fixation, dark respiration and (32)P-phosphate incorporation are reported for the silicon-starvation synchrony of the fresh water diatom Navicula pelliculosa. During late exponential growth the rates were consistent with increase in carbon mass. During silicon starvation, rates of carbon dioxide fixation, oxygen evolution and (32)P incorporation fell, and the saturating light intensity decreased from 27,000 lux to 5000 lux. Reintroduction of silicon led to immediate transients in all parameters studied, followed by a prolonged increase in rate of dark respiration and a gradual increase in apparent photosynthesis. During release of daughter cells, the rates of dark respiration decreased as photosynthesis and (32)P incorporation increased. These results are discussed in relation to effects of silicon on the energy metabolism of the diatom.