Averaged DA release (A) and rate of DA clearance (B) in striatum in 9cRA or vehicle treated hemiparkinsonian rats. (A) The peak amplitude of the DA signal, induced by local KCl administration, was averaged in lesioned (L, left) or non-lesioned (R, right) striatum of unilaterally 6-OHDA -lesioned rats. KCl-evoked DA release was almost abolished in the L striatum in vehicle treated rats. Treatment with 9cRA significantly increased DA release in the lesioned striatum. (B) The rate of DA clearance (nM/s) after KCl application was calculated between T20 and T60. There is a significant reduction in DA clearance in the striatum ipsilateral to the 6-OHDA lesioning in vehicle treated rats. 9cRA treatment significantly enhanced rate of DA clearance.