In vivo electrochemical studies of monoamine release in the medial prefrontal cortex of the rat.
The magnitude and duration of release of monoamines evoked by local applications of potassium were measured in vivo in the medial prefrontal cortex using high-speed chronoamperometry. Typical electrochemical signals reflecting released of electroactive species ranging from 0.5 to 3.0 microM and lasting 90-120 s were detected at a variety of dorsal-ventral and anterior-posterior electrode placements in the medial prefrontal cortex. The magnitude of the reduction current measured following the oxidation reaction suggests a contribution of both serotonin and dopamine to the electrochemical signal, dopamine serving as the predominant monoamine in the medial prefrontal cortex proper and serotonin appearing to predominant in the more posterior regions of the frontal cortex. This conclusion was reinforced by the fact that unilateral 6-hydroxydopamine lesions of ascending dopamine fibers almost completely abolished electrochemical signals in the ipsilateral but not in the contralateral medial prefrontal cortex. The present study provides an in vivo characterization of monoamine release in the mesocortical dopamine terminal field, where it has been suggested that psychomotor stimulants may produce some of their positive reinforcing effects.
Gratton
A
A
Department of Pharmacology, University of Colorado Health Sciences Center, Denver 80262.
Hoffer
B J
BJ
Gerhardt
G A
GA
D004298:Dopamine / Q000378:metabolism* / Q000494:pharmacology; D004563:Electrochemistry; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism* / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism* / Q000494:pharmacology
D012701:Serotonin; D011188:Potassium; D004298:Dopamine; D009638:Norepinephrine