Progressive paradoxical sleep deprivation impairs partial memory following learning tasks in rats

BACKGROUND： Complex learning tasks result in a greater number of paradoxical sleep phases, which can improve memory. The effect of paradoxical sleep deprivation, induced by ＂flower pot＂ technique, on spatial reference memory and working memory require further research. OBJECTIVE： To observe the effect of progressive paradoxical sleep deprivation in rats, subsequent to learning, on memory using the Morris Water Maze. DESIGN, TIME AND SETTING： Controlled observation experiment. The experiment was performed at the Laboratory of Neurobiology, Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Lanzhou University from December 2006 to October 2007. MATERIALS： Twenty-eight, male, Wistar rats, 3-4 months old, were provided by the Experimental Animal Center of Lanzhou University. The Morris Water Maze and behavioral analyses system was purchased from Genheart Company, Beijing, China. METHODS： All animals, according to a random digits table, were randomly divided into paradoxical sleep deprivation, tank control, and home cage control groups. Paradoxical sleep deprivation was induced by the ＂flower pot＂ technique for 72 hours, housing the rats on small platforms over water. Rats in the ＂tank control＂ and ＂home cage control＂ groups were housed either in a tank with large platforms over the water or in normal cages without paradoxical sleep deprivation. MAIN OUTCOME MEASURES： Morris Water Maze was employed for task learning and spatial memory testing. Rats in all groups were placed at six random starting points each day for four consecutive days. Each placement was repeated for two trials; the first trial represented reference memory and the second working memory. Rats in the first trial were allowed to locate the submerged platform within 120 seconds. Data, including swimming distance, escape latency, swimming velocity, percentage of time in correct quarter, and memory scores were recorded and analyzed automatically by behavioral analyses systems for Morris Water Maze. RESULTS： Twenty-eight rats were included in the final analysis, without any loss. In the first trial, between day 2 and 4, escape latency and swimming distance increased significantly in the paradoxical sleep deprivation group compared to the home cage control and tank control groups （P 〈 0.01）; percentage of time in correct quarter and memory scores, however, decreased in the paradoxical sleep deprivation group compared to the home cage control and tank control groups （P 〈 0.01）. The escape latency, swimming distance, percentage of time in correct quarter, and memory scores in the second trial was not significantly different among the three groups （P 〉 0.05）. CONCLUSION： Paradoxical sleep deprivation inhibits spatial reference memory, but not working memory.

The effects of inactivated SARS-CoV-2 vaccination and subsequent infection of pregnant mice on the behaviors of offspring

The mass inoculation of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccines to induce herd immunity is one of the most effective measures we can deploy in the fight against coronavirus disease 2019(COVID-19).Pregnant women are prone to a higher risk of COVID-19,and maternal infection is a risk fac-tor for a range of neurological disorders leading to abnormal behavior in adulthood.However,there are limited clinical data to support whether vaccination or infection post-immunization in pregnant women can affect the behavioral cognition of fetuses in adulthood.In this study,human angiotensin-converting enzyme 2 pregnant mice(F0 generation)were immunized with CoronaVac and then infected with SARS-CoV-2.Subsequently,we analyzed the behavioral cognition of their adult offspring(F1 gen-eration)using the open-field test and Morris water maze test.The adult F1 generation did not exhibit any impairments in spontaneous locomotor activity or spatial refer-ence memory.