A single link to the first track to allow the export script to build the search page
  • Addiction, Drugs
  • Information from Lay-Language Summaries is Embargoed Until the Conclusion of the Scientific Presentation

    485—Learning and Memory: Physiology II

    Monday, November 11, 2013, 1:00 pm - 5:00 pm

    485.02: Effect of prenatal stress on spatial learning and memory in male and female rats at three different ages: Effect of postnatal tactile handling

    Location: Halls B-H

    ">A. GUERRERO-AGUILERA1,2, C. RUBIO-OSORNIO3, S. GALVAN-ARZATE2, *S. RETANA MARQUEZ1;
    1BiologÌa de la Reproduccion, Univ. Autonoma Metropolitana, Mexico, DF, Mexico; 2Neuroquimica, 3NeurofisiologÌa, Inst. Nacional de Neurologia y Neurocirugia Manuel Velasco Suarez, Mexico D.F., Mexico

    Abstract Body: Prenatal Restraint stress induces cognitive impairment as a result of fetal corticosteroids exposure. Stressor timing determines the corticosteroids amount released during stress. On the other hand, the postnatal manipulation of prenatally stressed animals has been shown to improve the performance in different cognitive tests in juvenile animals. In this work, we evaluated the effects of postnatal tactile handling in prenatally stressed males and females at different ages.
    Pregnant female rats were randomly assigned to either control or prenatal stress groups. Prenatal stress paradigm used in this study was cold water immersion (CWI). Pregnant rats were exposed to the paradigm from day 15 to day 20 of gestation. Pregnant control rats were exposed to normal animal care and maintenance procedures during this period. Following birth, the litters were homogenized in offspring number. The weaning was at day 21 postnatal and the animals were randomly assigned to 16 experimental groups: Control and prenatal stress, female and male, age 1, 2 and 3 months (2x2x3). Four groups (female and male offspring) were daily tactile handled (60s), from birth until 3 months old. All rats performed Morris Water Maze (MWM). Learning period lasted 4 days (4 trials by day, 60s each). Two days after the learning period, the offspring performed one trial, and the last trial was performed one week later. The time to find the platform was recorded. Three days after the learning period, rats performed one trial without platform. The time spent in the quadrant and the crossings were recorded.
    Prenatal stress caused an increase in escape latencies in males and females of all the ages. The time spent in the quadrant and the crossings also increased. The effect of prenatal stress in MWM performance was higher in females. Three months old, prenatally stressed rats, and handled from birth, showed a better performance at MWM compared to non-handled ones. These data suggest that prenatal stress by CWI, which is a high intensity stressor, decreases offspring spatial learning and memory capability in both sexes at all ages evaluated. Neonatal handling can revert these deficiencies.

    Lay Language Summary: Prenatal Restraint stress induces cognitive impairment as a result of fetal corticosteroids exposure. Stressor timing determines the corticosteroids amount released during stress. On the other hand, the postnatal manipulation of prenatally stressed animals has been shown to improve the performance in different cognitive tests in juvenile animals.
    In this work, a major goal is to define periods of life in which the damage caused by prenatal stress is more critical and we evaluated the effects of postnatal tactile handling in prenatally stressed males and females at different ages.
    Pregnant female rats were randomly assigned to either control or prenatal stress groups. Prenatal stress paradigm used in this study was cold water immersion (CWI). Pregnant rats were exposed to the paradigm from day 15 to day 20 of gestation. Pregnant control rats were exposed to normal animal care and maintenance procedures during this period.
    Following birth, the litters were homogenized in offspring number. The weaning was at day 21 postnatal and the animals were randomly assigned to 16 experimental groups: Control and prenatal stress, female and male, age 1, 2 and 3 months (2x2x3). Four groups (female and male offspring) were daily tactile handled (tactile manipulation involves get the rats on the palm and fingers of the opposite hand (index, middle and ring) rubbed the back of the rat) by 60s, from birth until 3 months old.
    All rats performed Morris Water Maze (MWM). Learning period lasted 4 days (4 trials by day, 60s each). Two days after the learning period, the offspring performed one trial, and the last trial was performed one week later. The time to find the platform was recorded. Three days after the learning period, rats performed one trial without platform. The time spent in the quadrant and the crossings were video recorded.
    All animals showed decreased in the time spent it to find the platform during learning sessions but prenatal stress caused an increase in escape latencies in males and females of all the ages compared to non-stressed ones. When the animals performed the last probes at MWM showed impairment in the ability to remember the long-term test. Time spent at the quadrant where was the platform during the learning phase was smaller in the testing of males and females prenatally stressed (two and three months of age) compared to non-stressed ones. Furthermore, the number of crosses carried females (two and three months of age) and male (one and three months) was lower than the control animals which performed. The effect of prenatal stress in MWM performance was higher in females.
    Three months old, prenatally stressed rats, and handled from birth, showed a better performance at MWM compared to non-handled ones. These data suggest that prenatal stress by CWI, which is a high intensity stressor; this stressor is able to impair the ability to learn and memorize for juvenile and adult stage regardless of the age and sex of animals decreases offspring spatial learning and spatial memory capability in both sexes at all ages evaluated. Neonatal handling can revert these deficiencies.