Ethanol reinforcement is mediated by the opioid system, in 5 dayold rats

ABATE P.; GUTTLEIN L; MIRANDA MORALES RS; SPEAR N.E.

Huerta Grande, Córdoba

Congreso; XVII Congreso Anual de la Sociedad Argentina de Neurociencias; 2012

Sociedad Argentina de Neurociencias

Rat neonates (5-day?old) rapidly acquire an operant response explicitly reinforced with milk (Arias et al., 2007). We evaluated ethanol reinforcing effects in pups at this age, under similar experimental conditions. Additionally, we asked about the participation mu and kappa opioid sub-systems in mediating ethanol reinforcement. Exp. 1: 5-day-old pups were trained in an instrumental response (to press with their forelimbs or head). The reinforcers were sucrose (5%) or ethanol (3%). Two subjects were simultaneously tested. One pup received the reinforcer in contingency with the operant response, (experimental pup; E). At the same time, when E performed the operant response, other pup received the reinforcer (yoked subject; Y). Pups rapidly acquired an operant response, explicitly associated with the intraoral release of ethanol or sucrose. Exp. 2: before training, pups received an injection (i.p) of CTOP (mu antagonist), nor-BNI (kappa antagonist) or vehicle. We used ethanol as reinforcer. The blockade of both receptors resulted in the absence of increases in instrumental response, when comparing with control subjects. This result is the first in demonstrating that mu and Kappa opioid sub-systems are mediating ethanol reinforcing attributes, during the first week of life.