Neuronal c-Fos Reactivity of Medial Prefrontal Cortex and Basolateral Amygdala in Perinatally Underfed Lactating Wistar Rats

Abstract

Pre- and neonatal food restriction interferes with the neuronal and functional organization of longterm social adaptive responses including the maternal response to ensure pup survival. We addressed this issue by using low percentages of food from gestational days G6 to G 19 (50% to 30%) followed by a balanced diet from G20 to G21. After birth, pups were underfed by rotating two lactating dams, one with tied nipples, every 12 h. Weaning was at 25 days of age and thereafter an ad libitum diet. The F1 dams’ motivation (pup retrieval, handling shavings and crouching) was evaluated (10 min) at 4 and 12 days of lactation, when they had reached 90 days of age. The maternal neuronal functionality was measured by immunostaining the medial prefrontal cortex and the basolateral amygdala when the pups were removed from their dams 90 min after suckling. Underfed dams exhibited significantly lower pup retrieval, handling shavings and crouching frequencies, as well as prolonged latencies for pup retrieval and for handling shavings and crouching. Furthermore, early underfed dams had Fos-I neuron deficiencies mainly in the pre-frontal cortex, with minor effects on the amygdala, possibly because the pups’ cues to elicit maternal motivation were suboptimal and/or because of the deficient network activation.