Oxytocin is secreted in brain tissue and synthesized by the hypothalamus. This small, but crucial, feature deep in the brain controls biological reactions like hunger, thirst and body temperature, as well as visceral fight-or-flight reactions associated with powerful, basic emotions like fear and anger.

Farfetched? Swiss and American scientists demonstrate in new experiments how a squirt of the hormone oxytocin stimulates trusting behavior in humans, and they acknowledge that the possibility of abuse can't be ignored.

"Of course, this finding could be misused," said Ernst Fehr of the University of Zurich, the senior researcher in the study, which appears in today's issue of the journal Nature. "I don't think we currently have such abuses. However, in the future it could happen."

Therapy for Autism?

Other scientists say the new research raises important questions about oxytocin's potential as a therapy for conditions such as autism, in which trust is diminished.

Or, perhaps the hormone's activity could be reduced to treat more rare diseases, like Williams syndrome, in which children approach strangers fearlessly.

"Might their high level of trust be due to excessive oxytocin release?" asks University of Iowa neurologist Antonio Damasio, who reviewed the experiments for Nature. "Little is known about the neurobiology of trust, although the phenomenon is beginning to attract attention."

Controls Biological Reactions

Oxytocin is secreted in brain tissue and synthesized by the hypothalamus. This small, but crucial, feature deep in the brain controls biological reactions like hunger, thirst and body temperature, as well as visceral fight-or-flight reactions associated with powerful, basic emotions like fear and anger.

For years oxytocin was considered to be a straightforward reproductive hormone found in both sexes. In both humans and animals, this chemical messenger stimulates uterine contractions in labor and induces milk production. In both women and men, oxytocin is released during sex, too.