FORSTER*, G.L.; WATT, M.J.; BLAHA, C.D.; JOSS, J.M.P.; SUMMERS, C.H.; University of South Dakota; University of South Dakota; Macquarie University, Sydney, Australia; Macquarie University, Sydney, Australia; University of South Dakota: Testosterone Increases Striatal Dopamine Release in an Australian Agamid Lizard

Male Jacky Dragons (Amphibolurus muricatus) produce specific stereotyped motor displays to indicate aggression and territoriality, which are correlated with high levels of testosterone. Both elevated testosterone levels and striatal dopamine activity are correlated with aggression and stereotyped behaviors in mammals. As such, we investigated whether testosterone modulates extracellular striatal dopamine levels in territorial male Jacky Dragons. Nafion-coated carbon fiber recording electrodes were assessed in vitro and in vivo for dopamine sensitivity and selectivity. Following this, striatal dopamine oxidation currents (dopamine release) were measured via in vivo chronoamperometry (30 sec repetition period) within urethane-anaesthetized (1.5 g/kg, ip.) male Jacky Dragons that had previously established territories. Systemic application of a water-soluble form of testosterone (testosterone-HBC complex, 10 mg/kg, ip.) 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. Supported by a Macquarie University Research Grant.