Peripubertal stress increases play fighting at adolescence and modulates nucleus accumbens CB1 receptor expression and mitochondrial function in the amygdala

Summary & key facts

This rat study tested whether stress during the peripuberty period (seven non-consecutive days between postnatal day 28 and 42) changed play fighting at adolescence and later brain markers. Rats exposed to peripubertal stress showed more play fighting at P45. The researchers found that animals with very high play fighting in adolescence later showed abnormal adult aggression, faster habituation of corticosterone to repeated stress, and higher mitochondrial function in the amygdala, while animals with low play fighting showed higher CB1 receptor expression in the nucleus accumbens shell.

Key facts:

• The peripubertal stress (PPS) protocol used seven non-consecutive stress days between postnatal day (P)28 and P42.
• Play fighting was measured at P45 after 3.5 hours of social isolation. Measured behaviors were pinning, pouncing, boxing, and kicking; these were summed as total play fighting.
• PPS increased total play fighting at adolescence compared with control rats (reported by the authors).
• Animals were classified as “high players” if they scored above (or below for latency) the control group’s 80th/20th percentile cutoffs on at least 3 of 5 play measures (total duration, latency, frequency, percent pinning, percent pouncing).
• Rats identified as high players in adolescence later showed abnormal forms of aggression at adulthood (as reported in the study).
• High-player rats showed a rapid habituation of their corticosterone response to repeated stress during the peripuberty period (reported by the authors).
• High-player rats showed a marked increase in mitochondrial function measured ex vivo in the amygdala, but not in the nucleus accumbens (NAc).
• Low-player rats, but not high players, displayed increased expression of the CB1 cannabinoid receptor in the nucleus accumbens shell (reported by the authors).
• The study planned group sample sizes based on prior work and estimated they would need about 8 to 12 animals per experimental group.

Topics

Neuroendocrine regulation and behavior Stress Responses and Cortisol Tryptophan and brain disorders

Categories

Behavioral Neuroscience Life Sciences Neuroscience

Tags

Aggression Amygdala Central nervous system Clinical psychology Developmental psychology Extended amygdala Habituation Neuroscience Nucleus accumbens Psychology Psychopathology Stressor Stria terminalis