Oxytocin is hot. There are now hundreds of studies looking at the effect of this hormone on the human brain.
A dose of oxytocin, delivered in the form of a nasal spray, can make people nicer towards the ostracised, reduce marijuana cravings, and ‘enhance brain function’ in autistic children – and much more, if you believe it.
But not everyone does. Some doubt that nasal oxytocin even gets into the brain at all. Oxytocin is a peptide molecule, which means it can’t cross the blood-brain barrier and enter the central nervous system. Animal studies suggest that intranasal oxytocin might nonetheless get to the brain via some other route, perhaps along a nerve. But no-one has directly tested this in humans.
Now a new paper from Bonn, Germany claims to have put the fears to rest: Elevated cerebrospinal fluid and blood concentrations of oxytocin following its intranasal administration in humans.
They took 13 patients who were due to have a lumbar puncture (‘spinal tap’) for medical reasons. This procedure samples the cerebrospinal fluid (CSF) that surrounds the spinal cord and brain; if the oxytocin enters the brain, it would certainly be in the CSF.
The patients took either oxytocin or placebo nasal spray either 45, 60, or 75 minutes before the sample was taken, and oxytocin levels in the CSF were analyzed. Here’s what happened:
