[3H]GBR 12935 labels mainly the piperazine acceptor site in the rat prefrontal cortex

The binding characteristics of [3H]GBR 12935, a ligand for the dopamine (DA) transporter, have been extensively investigated in the striatum. The present study was designed to characterize [3H]GBR 12935-binding to prefrontal cortex (PFC) in rats. This region receives a dense DA input from the ventral tegmental area and is suspected to play a major role in higher associative functions. We demonstrated high-affinity, saturable, mazindol-sensitive [3H]GBR 12935-binding in the rat PFC; however, in contrast to the striatum, such binding was inhibited by increasing concentrations of Na+. This fact, together with the irregular pattern of the association kinetics and the marked sensitivity of [3H]GBR 12935-binding to piperazine derivatives, indicates the possible presence of more than one [3H]GBR 12935-binding site in the PFC. Furthermore, it appears that [3H] 12935 in the rat PFC labels mainly 'the piperazine acceptor site' and not the DA transporter.