Another hormone, vasopressin, contributes to male nurturance of offspring – it makes for caring fathers. It also has pain-killing effects and helps make animals venture out and be more exploratory. If vasopressin is blocked, there is immediately less paternal behavior. When injected directly into a section of the brain of male voles, vasopressin increased their paternal behavior. They couldn’t be loving fathers without it. Vasopressin is a counterbalance to oxytocin, creating more aggression and territoriality in animals.
Scientists recently took mice that are loners and injected a gene of vasopressin into them. This was taken from the prairie vole, known to be gregarious and faithful to its mate. Result: they became more social, more caring about female partners and spent more time with them. They were generally nice to them.
Both vasopressin and oxytocin have a role in brain maturation. When there is trauma early in the brain’s development, such as in the womb, the maturation of the brain is hampered. This is where the old adage, “We don’t have all our marbles,” comes from. A brain that suffers such impairment is a different brain, thanks in part to these two neuro-hormones. It is crucial when synapses are being organized and neuronal networks being set, that there is a proper balance between these neuro-hormones to support a healthy process of brain development.
Vasopressin and oxytocin, which are similar in molecular structure, can be traced back millions of years through evolution. We see from this that love and attachment have always been important to mammalian organisms, and closely related to sex and reproduction. Sexual activity increases oxytocin levels. In sexual arousal, vasopressin is at its peak, while oxytocin peaks during ejaculation. Vasopressin cells are concentrated in the amygdala, in the feeling centers of the brain. It is love that motivates us toward reproduction, towards sex. When there is little oxytocin, there is no attachment. When there is no attachment, there is no love. When there is no love, survival is at stake. Love, therefore, is a key survival mechanism, and that is why it plays such an important role in human social commerce. It is the first step toward survival of the species.
Male rats treated with vasopressin during the first week of life were more aggressive later on to strangers. Vasopressin, released when there is stress to the system, can be combated by oxytocin. This may seem strange, when they are so molecularly similar and can use the same receptors. Vasopressin plays a role in determining partner preference, and in some male animals encourages the selection of specific female partners. It is one essential element in pair bonding in animals. It is also associated with testosterone, which increases vasopressin levels.
When we “love” there is a chemical component. It is my hypothesis that the more intense the love feeling the higher the oxytocin level. And the reverse may also be true – the higher the oxytocin level, the more love there is to give. To be clear, love changes the entire physical system and can be measured in any number of systems. This is just another way of stating that the love we receive early in life helps our ability to love and have healthy sex later on. There is a hidden implication in all this, however: Even though we may swear we love someone, our biochemicals may betray us. So here is the second lesson: Stress, pain and anxiety are all enemies to love; they deplete our chemical supplies, the essential elements of love.
Research has shown, as I noted, that when the bellies of animals are stroked, not only is more oxytocin secreted into the system, but blood pressure drops, as well. Most importantly, there is a shift from sympathetic to parasympathetic dominance, as the relaxing, rest and repair system takes over to promote survival and good health. Love is calming and normalizing. While oxytocin helps lower blood pressure, pain raises it. That means a lack of love raises blood pressure, which is what we see in our patients; after one year of reliving pain, blood pressure drops an average of 24 points in the group. Oxytocin in animals inhibits the secretion of stress hormones, known as glucocorticoids. When the system is in a vigilant mode, the oxytocin levels drop and the anxiety system heightens. Oxytocin release is an important aspect of serotonin secretion. They work in harmony to help us repress pain.
Mother’s milk contains high levels of oxytocin. That is one reason why breast milk is so important in nursing young. It is sent directly to the suckling baby’s brain for comfort and calm. Research shows that mothers who nurse are calmer, more sociable, handle stress and monotony better, and have more skin-to-skin experiences with their baby. It has been found that when a newborn has not undergone a birth trauma and is able to suckle the mother’s breast right after birth, the gentle massaging by the infant’s mouth and hand increase the mother’s oxytocin level. What this does is enhance the mother-child bonding, producing an even greater closeness. So we have an increase in milk production and heightened maternal feelings, all wonderful for the baby. (“Alternatives.” Sept. 2001. The Numbing Down of America. Page 21)
If we prevent oxytocin production in a baby animal, preference and closeness to the mother does not occur. Bonding does not occur. When there is no closeness the baby suffers, perhaps for a lifetime. Attachment is a basic need. It is a two-way street: lowered Oxytocin in the baby prevents him feeling close to his parent. He becomes a baby who does not adore being cuddled, who squirms while being held. When the mother gives birth, her oxytocin levels rise dramatically, offering her the wherewithal to deeply love her baby. Some of that is transmitted to the baby. This biochemistry is telling us that love is essential. In the womb it has already been transmitted by the fact of love for her baby. That love, even when the baby has not been born yet, has chemical roots. Yes, the baby can feel loved in the womb. Not in the sense of comprehension, but of biology. That is why biology can speak volumes, even contradicting our thought processes which came along much later in human evolution.
In one experiment, women were encouraged to place their babies at the breast right after birth. The earlier the contact, the more physical the mother was later on with the newborn. We see more loving contact with early bonding. Lactation and nursing is one expression of loving a baby. The best preventive medicine – mental and physical – is love and its hormones.
Oxytocin is responsible for most ejaculations, including the “ejaculation” of mother’s milk to the baby and sexual ejaculation in the male. A mother who was loved as a child is apt to have more milk to breast feed her baby; and the male who was loved early on has more active sperm as an adult. Being unloved early in life may very well limit sperm production.
As I have indicated, oxytocin injections in animals facilitate the onset of maternal feelings. Of course, early parental love would eliminate that necessity. If you give a female sheep this hormone, she will adopt other infants for mothering, whereas without this hormone, she tends to reject outsider’s babies. When animals suckle they have higher levels of oxytocin. In rhesus monkeys that received oxytocin, there was an increase in touching, lip smacking and watching by mothers of their infants. Primate conduct parallels human behavior and the human brain; it is, therefore, quite important towards understanding human behavior.
How we feel, our attitudes about love, parenting and bonding, may well be dictated by our hormone state, and that, in turn, may be dictated by the set points of our hormones from experiences going all the way back to the womb. Those set points are fixed by the amount of love, or its lack very early in life. Early love gives us the capacity for love later on. It means a parent who looks lovingly at the child, who matches his mood, who touches and caresses softly, who listens without distraction. We may change our attitudes about love through exhortation by others, but we will not change our hormone state permanently.