In the hypothalamus, oxytocin is made in magnocellular neurosecretory cells of the supraoptic and paraventricular nuclei, and is stored in Herring bodies at the axon terminals in the posterior pituitary. It is then released into the blood from the posterior lobe (neurohypophysis) of the pituitary gland. These axons (likely, but dendrites have not been ruled out) have collaterals that innervate neurons in the nucleus accumbens, a brain structure where oxytocin receptors are expressed. The endocrine effects of hormonal oxytocin and the cognitive or behavioral effects of oxytocin neuropeptides are thought to be coordinated through its common release through these collaterals. Oxytocin is also produced by some neurons in the paraventricular nucleus that project to other parts of the brain and to the spinal cord. Depending on the species, oxytocin receptor-expressing cells are located in other areas, including the amygdala and bed nucleus of the stria terminalis.
Six hours later, the mice were returned to cages with the aggressive mice. The mice that were missing their oxytocin receptors didn't appear to remember the aggressive mice and show any fear. Conversely, when mice with increased numbers of oxytocin receptors were reintroduced to the aggressive mice, they showed an intense fear reaction and avoided the aggressive mice.
Melanotan II is a synthetic analogue of the α-melanocyte stimulating hormone (α-MSH). α-MSH is a melanocortin I receptor agonist which has a role in human pigmentation by stimulating production of eumelanin. As melanotan II is a non-specific melanocortin receptor agonist, it has been reported to cause toxicity effects involving the many physiological systems affected by the receptors.
A 2002 review concluded that although the data evaluated suggests that 5-HTP is more effective than placebo in the treatment of depression, the evidence was insufficient to be conclusive due to a lack of clinical data meeting the rigorous standards of today. More and larger studies using current methodologies are needed to determine if 5-HTP is truly effective in treating depression. In small controlled trials 5-HTP has also been reported to augment the antidepressant efficacy of the antidepressant clomipramine.