Limited changes of mouse maternal care after prenatal oxazepam: dissociation from pup-related stimulus perception

Abstract

There is evidence that activity at the GABA/benzodiazepine receptor complex in specific brain areas might be enhanced during rodent motherhood. We tested the hypothesis that the manipulation of this neurochemical system by prenatal benzodiazepine exposure affects typical behavioral responses of lactating mouse dams. Outbred CD-1 mouse fetuses were administered either oxazepam (OX, 15 mg/kg) or vehicle twice a day on embryonic days 12-16 and fostered at birth to untreated dams. Female offspring were subsequently mated at the young adult stage. In a first experiment, the behavioural repertoire of the two groups of lactating females was scored (single 10-min session) from postpartum days 3 to 18. When compared with VEH dams, OX females showed a shorter duration of pup-sniffing at 7-10 days and enhanced crouching behaviour when pups had reached the age of 14-18 days. In addition, OX-treated dams used more cotton for nest construction than the controls. The two female groups were differentiated only in the presence of their offspring. In a second experiment aimed at investigating possible OX-induced changes in pup-stimulus perception, the same lactating females were challenged in sequence on postpartum day 8 with three different patterns of pup-related cues consisting of: three 8-day-old live male pups (LP), three same-age dead pups DP, or three dead pups accompanied by pre-recorded ultrasounds (DPU). In the absence of carry-over effects of prenatal dam treatment, LP stimuli elicited a higher frequency of sniffing and digging than the others, whereas the level of licking, and grooming was reduced. In conclusion, the present results indicate that the slight alteration in maternal care resulting from prenatal OX treatment can be dissociated from changes in pup-related stimulus perception.

Pre-reproductive maternal enrichment influences rat maternal care and offspring developmental trajectories: behavioral performances and neuroplasticity correlates

“…To test the nest-building ability and proneness, each day from the day of delivery (ppd 0) till ppd 13 dams were given the opportunity to build a nest providing them 6 g of sterile surgical cotton placed on the lid of each cage, as described in previous studies (Schneider and Lynch, 1984; Laviola et al, 1990; Petruzzi et al, 1995; Venerosi et al, 2008). Quantitative index of nest building activity was the weight of the residual cotton.…”

“…Latency, frequency and duration of the following behaviors (Fleming and Rosenblatt, 1974; Petruzzi et al, 1995; Venerosi et al, 2008) were collected: - Pup-directed Behaviors: - Retrieving : the dam was picking up any pup in her mouth and carrying it to the nest;- Licking : the dam was licking or grooming any part of the pup's body, primarily the ano-genital region;- Sniffing : the dam was sniffing one or more pups;- Nursing : part of the litter was attached to dam's nipples while the dam did not show obvious back-arching;- Crouching (or arched-back nursing): the dam was domed over all pups with the body arched, hind-limbs splayed and no apparent movement;- Nest Building : the dam was pushing and pulling the sawdust toward the pups to form a nest.- Non pup-directed behaviors: - Digging : the dam was nuzzling in the sawdust out of nest area, pushing and kicking it around using the snout and/or both fore- and hind-paws;- Grooming : the dam was wiping, licking, combing or scratching any part of its own body;- Wall Rearing : the dam was rearing on hindlimbs, while leaning (or not) with the forelimbs on the cage walls, often sniffing the air;- Exploring : the dam was moving around the cage and sniffing the substrate, but not carrying pups or nesting material;- Resting : the dam was lying down alone, out of the nest.- Other behaviors: all behaviors different from the ones classified in the previous categories.…”

Influence of Pre-reproductive Maternal Enrichment on Coping Response to Stress and Expression of c-Fos and Glucocorticoid Receptors in Adolescent Offspring

“…Observations collected during the dark phase of the light/dark cycle were performed under dim red light illumination. Within each observation period the following behaviors of mothers were scored for duration and frequency (Fleming and Rosenblatt, 1974; Petruzzi et al, 1995; Venerosi et al, 2008; Cutuli et al, 2015): Pup-directed Behaviors :Retrieving: the dam was picking up any pup in her mouth and carrying it to the nest;Licking: the dam was licking or grooming any part of the pup's body, primarily the anogenital region;Sniffing: the dam was sniffing one or more pups;Nursing: part of the litter was attached to dam's nipples while the dam did not show obvious back-arching;Crouching (or arched-back nursing): the dam laid over all pups with the body arched, hind-limbs splayed, and no apparent movement;Nest Building: the dam was pushing and pulling the sawdust or the plastic tube toward the pups to form or adjust the nest. Non-pup-directed behaviors :Digging: the dam was nuzzling in the sawdust out of nest area, pushing and kicking it around using the snout and/or both fore- and hind-paws;Grooming: the dam was wiping, licking, combing or scratching any part of its own body;Wall Rearing: the dam was rearing on hindlimbs, while leaning (or not) with the forelimbs on the cage walls, often sniffing the air;Exploring: the dam was moving around the cage and sniffing the substrate, but not carrying pups or nesting material;Resting: the dam was lying down alone, out of the nest;Drink or Eat: the dam was drinking or eating, out of the nest. Other behaviors: all behaviors different from the ones classified in the previous categories. …”

Important Hints in Behavioural Teratology of Rodents

“…Mean (± SEM) frequency of pup-directed activities observed on postpartum day 8 in mouse lactating females exposed to live pups, dead pups, or dead pups accompanied by pre-recorded ultrasounds (n=8). Data of vehicle dams are represented, significant effects of prenatal oxazepam treatment were not observed (data from [113]). experimental conditions have to be accurately monitored to discriminate treatment effects [107][108][109][110][111].…”