Dopamine/adenosine interaction in effort-related processes in rodents: Studies using T-Maze paradigm in mice

Catorzenes Jornades de Foment de la Investigació de la FCHS (Any 2008-2009)Humans and animals realize cost/benefits analysis of our responses with the goal of use the lowest energy possible to obtain the major benefit. Mesolimbic dopamine (DA) is a critic component in the cerebral circuitry regulating decision making based on the effort that the response requires, because it regulates behavioral activation. Research with rodents show that DA antagonists displace the behavior from the response that supposes more effort, though it has more reinforcement, to other behavior with less effort required. Interaction between A2A adenosine receptors and D2 receptors play an essential paper in these processes. In the T-Maze paradigm the animal is exposed to an option of choose one arm with two food pellets, to which it accedes after climbing a 14 cm barrier, or to choose the arm without barrier and with only one food pellet. Control animals choose to do the effort of climbing the barrier to obtain the high reinforcement. Haloperidol, D2 antagonist, produces change behavior towards the less density arm, been this effect partially reverted with theophylline, unspecific adenosine antagonist, and with MSX-3, selective A2A antagonist. These drugs could have applications for the treatment of amotivational syndromes