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Scientists Develop Nasal Spray for Mental Illness
Researchers in Sweden have tested a new device for delivering hormone treatments for mental illness through the nose. The method was found to deliver medication to the brain with few adverse effects, according to a study published in Translational Psychiatry.
Oxytocin is a hormone that influences social behavior and has shown promise for the treatment of mental illness. Researchers at the University of Oslo found that low doses of oxytocin may help patients with mental illness to better perceive social signals. As part of this project, they collaborated with a company called Optinose, which has developed a device designed to improve drug delivery to the brain via the nose.
Oxytocin, a neuropeptide, is known to play a crucial role in child rearing as it facilitates pregnancy, birth, and the release of milk during nursing. Moreover, the peptide helps regulate cardiac functions and fluid levels. Recent research has also revealed the importance of oxytocin for social behavior.
Peptides are a group of molecules that consist of a chain of amino acids. Amino acids are also known as the “building blocks” of proteins. Oxytocin is produced in the hypothalamus –– the brain’s coordinating center for the hormone system.
Because oxytocin is a relatively large molecule, it has difficulty crossing the blood–brain barrier (BBB). Researchers have therefore administered the peptide to patients through the nose, as this route offers a direct pathway to the brain that bypasses the BBB.
Professor Ole Andreassen and his colleagues collaborated with OptiNose on a project that evaluated how two different doses of oxytocin affected the way in which social signals are perceived.
Sixteen healthy men received oxytocin along with placebo. Volunteers were also given an intravenous dose of oxytocin for a comparison of the effects of oxytocin in circulating blood. The researchers found that only a low dose of oxytocin affected how subjects perceived social signals.
“The results show that intranasal administration, i.e., introducing oxytocin through the nose, affects the function of the brain,” Andreassen explained. “As no effect was observed after intravenous treatment, this indicates that intranasally administered oxytocin travels directly to the brain, as we have long believed. The fact that we have shown the efficacy of a low dose of oxytocin on social perception is even more important. A dose that is lower, but that still influences behavior, will entail a lower risk of affecting other regulatory systems in the body. Very high doses of oxytocin could, in fact, have the opposite effect on social behavior.”
The investigators also discovered that individuals with larger nasal cavities had a stronger response to a low dose of oxytocin.
The OptiNose device administers oxytocin high up into the patient’s nasal cavity. When the drug is targeted deep inside the nose, it enables brain delivery along nerve pathways from the uppermost part of the nasal cavity. The device also expands the nasal cavity, facilitating nose-to-brain delivery of medications. As the user exhales into the device, his or her breath closes the soft palate and prevents the medication from being lost down the throat. Since less drug is lost, patients can take smaller doses.
The researchers are now performing tests of the Optinose device in volunteers with autism spectrum disorders.
Sources: Medical Xpress; August 28, 2015; and Translational Psychiatry; July 14, 2015.