Love and anger are powerful emotions, the basis of lasting social bonds and hierarchies, aggression and defense, and marriage. When neurohormones combine with thinking and behavior, we feel emotions. A brain cocktail of vasopressin, oxytocin, and dopamine can produce feelings of being in love just as surely as increased levels of cortisol and adrenalin produce the feelings of anger or rage. Like other hormones, vasopressin, oxytocin, and cortisol exert one set of physiological effects on target tissues in the body and very distinct behavioral effects in the brain. When researchers inhibit these specific hormones or block their specific hormone receptors in the brain, especially receptors in the limbic system, subjects report no feelings of love or anger. Without hormones – we have no emotions. With too many, we go ballistic. Love is just right.
So that subjects with lowered levels of vasopressin report increased marital strife and infidelity. With low vasopressin feelings of emotional bonds slip out the door. When vasopressin receptors in the brain are entirely blocked males lose all arousal and attraction. Similarly, males who carry a variant of the vasopressin receptor produced by the “1a gene” show low vasopressin and are much less likely to stay married.
So too with oxytocin, which acts peripherally to stimulate breasts as “milk let-down factor,” but also acts within the brain as a powerful attraction and bonding agent for both women and men. Men release oxytocin during orgasm, but only with someone they love. With women, low levels of oxytocin causes mothers to reject their young. Blocking oxytocin receptors in the brain also blocks feelings of love and emotional closeness altogether. With high levels of oxytocin, both men and women fall in love. Without oxytocin, as without vasopressin, that loving feeling falls flat.
The neuroenhancing release of vasopressin and oxytocin not only changes the way we feel and think about our partners, but these hormones create the glue that makes relationships stick. When “love is blind,” these two hormones act like cheap sunglasses and keep us “attached at the hip.”
Couples who report “being lovestruck,” and who have volunteered to literally “have their heads examined” show a surge of dopamine concentrations in the emotional hub of the brain, the limbic system.High levels of dopamine here can produce intense pleasure with little thought of food or sleep; low levels produce the tremors of Parkinson’s disease. Is “chemistry” important for love and anger? No, chemistry is everything.
Successful patients have learned to motivate their own healing….If we knew what their brains were doing to motivate their bodies we would have the basic unit of the healing process in our hands.