Changes in experimental anxiety during pregnancy and lactation

Area of Science:

• Neuroscience
• Behavioral Endocrinology
• Animal Behavior

Background:

• Experimental anxiety is often studied in rodents to model human stress responses.
• Pregnancy and lactation involve significant hormonal shifts that can impact maternal behavior and neurochemistry.

Purpose of the Study:

• To investigate changes in experimental anxiety and reactivity in female rats during pregnancy and lactation.
• To analyze the effects of pregnancy and parturition on burying behavior and locomotor activity.

Main Methods:

• The burying behavior test was employed to assess anxiety, measuring cumulative burying, latency, and shocks needed.
• Ambulatory (locomotor) behavior was simultaneously evaluated in pregnant, lactating, and ovariectomized control rats.
• Behavioral tests were conducted on specific days of gestation (7th, 14th, 21st) and lactation, including a group tested 12 hours post-parturition.

Main Results:

• A significant increase in burying behavior latency and a decrease in cumulative burying were observed at the end of pregnancy.
• Burying behavior was notably reduced immediately after parturition.
• Locomotor activity showed changes during pregnancy but not lactation; these changes did not fully account for the observed anxiety reductions.
• The number of shocks required for burying behavior remained unchanged, except for a decrease on the 7th lactation day.

Conclusions:

• Hormonal factors, potentially progestins, may contribute to the reduced anxiety observed during gestation.
• Neurotransmitter variations, specifically serotonin and beta-endorphins, likely influence the anxiety changes seen during lactation.