Adolescent intermittent ethanol exposure does not alter responsiveness to ifenprodil or expression of vesicular GABA and glutamate transporters

Binge eating promotes ethanol self-administration in female rats with a history of intermittent ethanol exposure at adolescence

BACKGROUND

Ethanol drinking begins during adolescence and, particularly when occurs in a binge-like pattern, exerts lingering adverse consequences. Pre-clinical studies indicate that intermittent ethanol exposure (IEA, a model of repeated ethanol intoxication), or binge eating (BE) can increase subsequent ethanol consumption. It is unknown if the promoting effects of BE upon ethanol drinking are found in female rats and are modulated by IEA at adolescence. This study assessed interactive effects between IEA and BE, upon ethanol drinking.

METHODS

Female Wistar rats were given 4.0 g/kg ethanol, every other day from postnatal day 25-45. At adulthood, they were exposed to sessions in which a brief offering of a sizeable portion of highly palatable sugary pills was followed by a 120-min exposure to an ethanol bottle.

RESULTS

Exploratory activity and recognition memory was not affected by the IEA. Glutathione peroxidase and catalase activity, and lipid peroxidation (measured in blood and brain at the end of the procedure) were not significantly affected by IEA or BE exposure. BE alone had a mild promoting effect on ethanol ingestion. Those rats that underwent IEA and BE, however, exhibited heightened and sustained ethanol self-administration (average of 2.12 g/kg/120 min, vs 1.15 g/kg/120 min of the other groups), that persisted throughout the BE sessions. IEA and a history of BE also promoted ethanol intake or preference in a two-bottle endpoint test.

CONCLUSION

The study suggests that exposure to IEA exerts, when followed by BE at adulthood, promoting effects upon ethanol intake, particularly at concentrations ≥ 6%.

Neuroplasticity and Multilevel System of Connections Determine the Integrative Role of Nucleus Accumbens in the Brain Reward System

A growing body of evidence suggests that nucleus accumbens (NAc) plays a significant role not only in the physiological processes associated with reward and satisfaction but also in many diseases of the central nervous system. Summary of the current state of knowledge on the morphological and functional basis of such a diverse function of this structure may be a good starting point for further basic and clinical research. The NAc is a part of the brain reward system (BRS) characterized by multilevel organization, extensive connections, and several neurotransmitter systems. The unique role of NAc in the BRS is a result of: (1) hierarchical connections with the other brain areas, (2) a well-developed morphological and functional plasticity regulating short- and long-term synaptic potentiation and signalling pathways, (3) cooperation among several neurotransmitter systems, and (4) a supportive role of neuroglia involved in both physiological and pathological processes. Understanding the complex function of NAc is possible by combining the results of morphological studies with molecular, genetic, and behavioral data. In this review, we present the current views on the NAc function in physiological conditions, emphasizing the role of its connections, neuroplasticity processes, and neurotransmitter systems.