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The Effect of Exposure to Sound Stress during Lactation on Cognitive Behaviors and Synaptic Plasticity in the Hippocampus of Rat Offspring
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F Aghighi    , M Salami , SA Talaei * |
| 1.Physiology Research Center, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, I.R.Iran. , talaei@kaums.ac.ir |
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Abstract: (43 Views) |
Background and Objective: The critical period of brain development is a period of pre- and post-natal life, in which the interaction of genetics and environmental signals leads to the formation of synaptic communication. Facing chronic stress during breastfeeding can affect the neurobiological development of children. This study aims to investigate the effect of exposure to sound stress during lactation on spatial learning and memory, as well as the synaptic plasticity in the rats’ offspring.
Methods: This experimental study was conducted on 4 groups of 45-day-old male Wistar rats (n=10): control group (CON), offspring whose mothers were lactating daily for 1 (ST1) or 2 (ST2) or 4 hours (ST4) were exposed to sound stress with an intensity of 95 dB. The spatial learning and memory of animals were examined using the Morris water maze. Basic field excitatory post-synaptic potentials were recorded in the CA1 area of hippocampus and, then, long-term potentiation (LTP) was induced by high-frequency stimulation. The serum corticosterone levels of rats were measured at the end of the study.
Findings: In the ST4 group, the elapsed time and distance traveled to find the hidden platform increased compared to the CON group (p<0.001). Also, compared to CON rats (13.23±0.74 sec) the staying time in the target quadrant decreased in the ST4 group (8.91±0.45 sec) (p<0.001). Tetanic stimulation induced long-term potentiation (LTP) in the neurons of the CA1 region of the control group (0.9±0.01 mv), and vice versa in the ST4 group (0.5±0.02 mv) induced long-term depression (LTD). The serum corticosterone of the ST4 rats (128.50±4.80 nmol/lit) was significantly higher than that of the control group (97.63±2.90 nmol/lit) (p<0.001).
Conclusion: Exposure of lactating rats to sound stress by increasing the serum corticosterone levels of offspring caused impairment of learning and spatial memory as well as synaptic plasticity of CA1 neurons in their hippocampus in adulthood. |
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| Keywords: Stress, Lactation, Hippocampus, Spatial Learning, Synaptic Plasticity, Rats. |
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Type of Study: Interventional |
Subject:
Physiology
Received: 2024/06/7 | Accepted: 2024/10/12
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