Neonatal Ethanol Exposure but not Neonatal Cocaine Selectively Reduces Specific Isolation-Induced Vocalization Waveforms in Rats

Abstract

This study was designed to examine the interaction of neonatal ethanol and cocaine exposure on isolation induced ultrasonic vocalizations using an oral gavage method of drug administration. There were 5 neonatal treatment groups including 3.0 g/kg ethanol, 20 mg/kg cocaine, both 3.0 g/kg ethanol and 20 mg/kg cocaine, an intubated control and a nonintubated control. Drug was administered twice daily from postnatal days (PND) 4 - 10. On PND 14, subjects were tested for a 6 min test to assess the rate and type of ultrasonic vocalizations displayed. As previously reported using an intragastric "artificial rearing" administration procedure, pups exposed to ethanol displayed reductions in the number of ultrasonic vocalizations across the test session. Pups exposed to both drugs showed similar deficits to those pups receiving ethanol alone. In contrast, cocaine had no effect on this outcome measure. Sonographic analysis of the vocalizations revealed that ethanol's effects appeared to be selective to certain waveforms rather than a general reduction across all wave types and again, cocaine had no impact on the proportion of the various wave types. These findings provide further support that neonatal ethanol exposure can have significant effects on maternal/infant communication and may play a role in many of the long-term effects associated with ethanol exposure during development.

Effects of Genetic Background, Gender, and Early Environmental Factors on Isolation-Induced Ultrasonic Calling in Mouse Pups: An Embryo-Transfer Study

“…The finding that early environmental factors can influence calling behavior is in accordance with studies on the effects of prenatal malnutrition (Tonkiss et al 2003), prenatal stress (Morgan et al 1999;Williams et al 1998), perinatal asphyxia (Calmandrei et al 2004) or pre-and postnatal exposure of various substances, like alcohol (Barron and Gilbertson 2005;Marino et al 2002;Tatolli et al 2001), cocaine (Hahn et al 2000), lead (De Marco et al 2005), aluminum (Alleva et al 1998), or carbon monoxide (Di Giovanni et al 1993) on ultrasonic calling in infant rodents. However, in the natural context, variations in maternal care might be of major importance.…”

Ontogeny in the Family

“…The only direct test I know of was carried out on gerbils (Meriones unguiculatus and reported a non-significant effect (McCauley and Elwood, 1984). Additional indirect evidence for such a role of USV is suggested by studies showing increased prolactin release in lactating rat dams exposed to pup USV (Hashimoto et al, 2001;Terkel et al, 1979; see also Barron and Gilbertson, 2005). Because maternal milk is critical for pup survival and development, and is one of the major and probably most costly resources provided by mammalian mothers (Clutton-Brock, 1991), a pup solicitation trait signaling nutritional requirements may be expected.…”

“…The partitioning into a fixed baseline and a socially responsive component may also be of interest in experiments investigating the effects of drugs on USV as a model for infant anxiety syndromes (see Barron and Gilbertson, 2005;Brunelli, 2005;Burgdorf et al, 2005;D' Amato et al, 2005). The preferential target of such drugs might be the baseline component.…”

Ultrasonic vocalizations in house mice:

“…Food-deprived mice produce USVs at lower rates than those produced by well-nourished individuals (Moles and D'Amato, 2000). Similarly, malnutrition leads to a reduction of specific call types in rat pups (Barron and Gilbertson, 2005). The production of USVs may be particularly costly for food-restricted animals, a hypothesis suggested in several empirical studies.…”

“…Vocalizations are thought to be modulated by emotional/motivational mechanisms governed by the limbic system (Ehret, 2005). Receptor systems of the brain are the target for modulating neurotransmitters, such as serotonin and dopamine, and other neuromodulators, such as opioids and cholecystokinin, which can both facilitate and inhibit USV production (Barron and Gilbertson, 2005;Ehret, 2005;Hofer, 2010). Interestingly, the profile of neurotransmitters involved in separation vocalization in infant pups is very similar to the neurotransmitter pattern that mediates human anxiety and is also thought to influence separation anxiety in children (Hofer, 2010).…”