The agranular insular cortex: a site of unusually high dopamine utilisation.

Dopamine (DA) utilisation (expressed as homovanillic acid:DA) was compared in the medial prefrontal cortex (FCx), the agranular insular cortex (AgCx), the caudate-putamen (medial, CPM and lateral, CPL divisions) and the nucleus accumbens (NAc). DA utilisation in these regions decreased in the order AgCx greater than FCx greater than CPM, CPL, NAc, whilst the concentration of DA decreased in the reverse order. Thus, although fewer DA neurones appear to innervate AgCx compared with FCx, the rate of DA utilisation/release is much greater in AgCx. It is suggested that this apparently more marked activity in DA neurones innervating AgCx may reflect a relative lack of autoreceptor control.