Received for publication March 17, 2006.
Revised July 4, 2006.
Accepted for publication July 5, 2006.

Heterogeneous dopamine neurochemistry in the striatum: the fountain-drain matrix

Abstract

In contrast to the relatively high attention paid to the structural heterogeneity of striatal dopamine (DA) innervation, little attention has been focused on the possible striatal heterogeneity for release and uptake of DA. By using amperometric methods, we found striatal regions showing a DA-decrease during the medial forebrain bundle stimulation (drain areas) near to other zones that showed an increase in DA-concentration (fountain areas). Both areas were intermixed to form a tri-dimensional matrix to regulate DA-concentration throughout the striatum (fountain-drain matrix). The response to electrical stimuli of different amplitudes and durations and to different drugs (-methyl-l-tyrosine, cocaine, gamma-butyrolactone and haloperidol) suggests that regional differences for both DA-release/DA-uptake and DA-cell firing autoregulation are behind the striatal fountain-drain matrix. The high-diversity of DA-activity observed in the striatum is a new framework for analyzing experimental and clinical phenomena.

Key words: DAT, cocaine, dopamine, haloperidol, nigro-striatal system, striatum