Rapid testosterone modulation of striatal dopamine release

Male Jacky Dragons (Amphibolurus muricatus) produce specific stereotyped motor displays to indicate aggression and territoriality, which are correlated with high levels of testosterone. As both elevated testosterone levels and striatal dopamine activity are correlated with aggression and stereotyped behaviors in mammals, we aimed to investigate whether testosterone modulates extracellular striatal dopamine levels in territorial male Jacky Dragons. After in vitro and in vivo assessment of nafion-coated carbon fiber recording electrode sensitivity and selectivity for dopamine, striatal dopamine oxidation currents (dopamine release) were measured via in vivo chronoamperometry (30 sec repetition period) within urethane-anaesthetized (1.5 g/kg, i.p.) territorial male Jacky Dragons. Systemic application of a water-soluble form of testosterone (testosterone-HBC complex, 10 mg/kg, i.p.) resulted in increased striatal dopamine release within 10 minutes, implying a rapid effect of testosterone on striatal dopamine activity. We conclude that testosterone may act upon the male Jacky Dragon nigrostriatal dopamine system to produce stereotyped motor displays used to convey aggression and territoriality