In contrast to the results from previous studies (Cassilhas et al., 2012b, Liu et al., 2009 and Radak et al., 2006), the IA performance was not enhanced by physical exercise in the present study. Cassilhas et al. (2012b) found a memory improvement in rats subjected to 8 weeks of resistance exercise

when compared with the memory of their sedentary counterparts. Moreover, the performance in this task appears to be dependent on the type of exercise employed. For example, Liu et al. (2009) demonstrated that moderate treadmill exercise (forced) and voluntary wheel running affected the IA performance differently; animals subjected to the former had an improvement in long-term memory,

but the latency of the voluntary group did not differ from that of the sedentary controls. The lack of differences in IA performance between Staurosporine mouse the Ex and SC groups can be explained, at least in part, by the use of a very intense protocol during the training for the behavioral task. Thus, studies that verified a memory improvement as a result of physical exercise used a lower negative reinforcer (1 footshock of 0.2–0.5 mA) during IA training (Cassilhas et al., 2012b, Liu et al., 2009 and Radak et al., 2006) than that used in this work (5 footshocks of 0.8 mA). The higher number and intensity of footshocks during the IA training may have led to the occurrence of a ceiling effect on the IA performance. For example, Cruz-Morales et al. (1992) selleckchem found that the amnesic effect triggered by systemic administration of scopolamine, a cholinergic antagonist, was not present when the intensity of footshocks was increased during IA training. Therefore, it is possible that the observed absence of differences between the Ex and SC groups in the present study was due to the occurrence of a ceiling effect. Previous studies have extensively documented that the formation of long-term memories requires changes in proteins synthesis, gene expression and the structural properties of neurons and synapses (Costa-Mattioli

et al., 2009 and Sultan and Day, 2011). Furthermore, one of the mechanisms underlying learning and memory requires Carbachol the involvement of several synaptic proteins needed for the proper synaptic transmission, such as synapsin I, synaptophysin, GAP-43 and PSD-95 (Clare et al., 2010, Powell, 2006, Silva et al., 1996 and Xu, 2011). The growth-associated protein GAP-43 is a neuron-specific protein found in high concentrations in growth cones and pre-synaptic terminals and is closely associated with neuritogenesis, synaptic plasticity and regenerative processes (Aigner et al., 1995, Oehrlein et al., 1996 and Oestreicher et al., 1997). Moreover, GAP-43 plays a central role in learning and memory. For instance, Rekart et al.