I've found a way to copy/paste from Kindle! Their software reader, at least the Windows version, allows copying:

You may wonder how researchers did most of the oxytocin experiments related to bonding. They piped it (or drugs that neutralized it) directly into rodents’ brains— onto spots no larger than peppercorns. However, even if you could pipe it into an unloving mate’s brain, you’d have to squirt it in every time you were together. Bonds are only created when oxytocin is consistently released in response to a particular person.

Next time you read about the wonders of oxytocin, keep in mind that the only feasible way to deliver it to anyone’s brain today is by way of a nasal spray— and that is not such a good idea. Such sprays have been used for a long time to induce milk letdown, but the oxytocin ends up all over the brain and circulating in the blood.

In contrast , your body delivers neurochemicals in just the right amount, precisely to the places they are needed, for as long as they are needed, and then quickly disposes of them. A shotgun approach can cause unintended consequences and alter the brain itself. A rise in oxytocin in a minuscule part of a mother rat’s brain causes her to guard her young fiercely. The same rise one-tenth of an inch away makes her passive. 277 Manipulating humans with oxytocin is also dodgy. When scientists tried to relieve symptoms of obsessive-compulsive disorder long-term, using oxytocin nasal spray, it caused severe memory disturbances, psychotic symptoms, and marked changes in blood sodium levels. 278 In another experiment it brought on high blood sugar (diabetes). 279

At present researchers only use oxytocin nasal sprays for short-term experiments— to learn the kinds of behaviors it influences. In this way it became evident that oxytocin increases trust— by calming the amygdala. 280 Spraying your brain is a fine tactic if you want to trust everyone, including Wall Street bankers, used car salesmen, and politicians. For example, in one experiment, those who took the placebo did not reinvest