Oxytocin
It has been shown that oxytocin differentially affects males and females. Females who are administered oxytocin are overall faster in responding to socially relevant stimuli than males who received oxytocin. Additionally, after the administration of oxytocin, females show increased amygdala activity in response to threatening scenes; however, males do not show increased amygdala activation. This phenomenon can be explained by looking at the role of gonadal hormones, specifically estrogen, which modulate the enhanced threat processing seen in females. Estrogen has been shown to stimulate the release of oxytocin from the hypothalamus and promote receptor binding in the amygdala.
Oxidopamine
The main use for oxidopamine in scientific research is to induce Parkinsonism in laboratory animals such as mice, rats and monkeys, in order to develop and test new medicines and treatments for Parkinson's disease. In order to induce this condition in animals, around 70% of the dopaminergic neurons in the substantia nigra of the brain must be destroyed, and this is achieved either with oxidopamine or MPTP. Both these agents likely destroy neurons by generating reactive oxygen species such as superoxide radical. Oxidopamine toxicity in neonatal rodents is also used as an animal model for the Lesch-Nyhan syndrome.