Maturation of the dopamine innervation during postnatal development of the prefrontal cortex in gerbils (Meriones unguiculatus). A quantitative immunocytochemical study

Dopamine (DA)-immunoreactivity was investigated in the prefrontal cortex of gerbils (Meriones unguiculatus). For that purpose, a sensitive and selective antibody against glutaraldehyde-conjugated dopamine was applied. All detectable fragments of dopamine-immunoreactive nerve fibres were identified in selected consecutive frontal sections and their total length was determined in both the medial and orbital prefrontal cortex on postnatal days 7, 14, 23, 30, 60, and 90. Dopamine immunoreactivity revealed exponential growth until postnatal day 30, and further increased until postnatal day 90 with reduced increments. Due to higher initial percentage growth rates the dopamine innervation in the orbital prefrontal cortex achieved maturity earlier than in the medial prefrontal areas. Quantitative maturation of the prefrontal DA innervation is discussed with current data on functional and structural development of the prefrontal cortex.