My classmates know it. My friends know it. Almost everyone I meet knows it. It's pretty clear. I am obsessed with oxytocin. What is oxytocin??
Oxytocin is a peptide hormone and neurotransmitter made in the hypothalamus. To the left is the molecular structure of oxytocin.
From the hypothalymus, oxytocin is either sent to different parts of the brain (acting as a neurotransmitter), or stored in the posterior pituitary for release into the bloodstream as a hormone. Below is a picture of oxytocin in the posterior pituitary waiting to be released (photo from my Tissue and Organ Biology course at Tufts).
But why am I so obsessed with oxytocin?!
In an endocrinology course in undergrad and again in a very recent physiology lecture here at Tufts Med, I learned that oxytocin is used to make the uterus contract during childbirth and to release or "let down" breast milk so mom can nurse baby. That was it. One slide, a few bullets, no big deal, not very exciting. But like most hormones, oxytocin is pleiotropic - it is made by one gene, but does a heck of a lot more than one thing. Oxytocin not only acts on the breast and uterus, it also can affect the brain, kidney, heart, etc. Oxytocin plays a huge part in biological and behavioral components of human life and is vital to successful development, successful relationships, and successful reproduction.
Oxytocin's involvement in human romantic relationships is really what drew me in. This one hormone seemed to explain why life and relationships are the way they are.
In an endocrinology course in undergrad and again in a very recent physiology lecture here at Tufts Med, I learned that oxytocin is used to make the uterus contract during childbirth and to release or "let down" breast milk so mom can nurse baby. That was it. One slide, a few bullets, no big deal, not very exciting. But like most hormones, oxytocin is pleiotropic - it is made by one gene, but does a heck of a lot more than one thing. Oxytocin not only acts on the breast and uterus, it also can affect the brain, kidney, heart, etc. Oxytocin plays a huge part in biological and behavioral components of human life and is vital to successful development, successful relationships, and successful reproduction.
Oxytocin's involvement in human romantic relationships is really what drew me in. This one hormone seemed to explain why life and relationships are the way they are.
Lucky for me, oxytocin has been gaining popularity recently. It has been dubbed the fantastic nicknames of the "Love Hormone" or "Cuddle Hormone." Scientists are currently studying tons of different ways oxytocin is involved in the function or dysfunction of our bodies, relationships, and minds, and they have started discovering potential ways oxytocin can help people suffering from a variety of problems.
So in this post, I am going to attempt to explain some of the wonderful things oxytocin does. I will try to keep it short, but I am obsessed, so bear with me or skip to a section that interests you!
So in this post, I am going to attempt to explain some of the wonderful things oxytocin does. I will try to keep it short, but I am obsessed, so bear with me or skip to a section that interests you!
1. Oxytocin and Bonding
When a baby breastfeeds, oxytocin is released to let down the milk in the mom's breasts. This oxytocin also warms the mother's body so the baby is comfortable. The baby is warm, has cozy cuddly feelings from oxytocin, is receiving some delicious nourishment from mom, and is able to build trust. Meanwhile, mom is being rewarded by oxytocin to continue to nourish, love, coo at, entertain, and protect her baby. Oxytocin also promotes pro-social behavior by increasing gaze to the eye region of the human face. I assume that eye gaze starts during breastfeeding, and continues to promote social interaction throughout life.
Oxytocin also promotes social recognition. In rodents, the ability to recognize and process odors of friends and enemies is enhanced by oxytocin. In humans, it helps us remember and recognize faces (way less cool, but hey, probably way more pleasant!). This aspect of oxytocin is crucial to creating and maintaining friendships and relationships. Oxytocin also regulates social memories, displays of friendly as well as aggressive behaviors, and by reducing stress hormones, allows us to trust the faces we see frequently.
While this is awesome, and a great benefit of oxytocin, we need to be careful. These effects cause us to trust people more readily (on oxytocin, study participants will give strangers more money - generosity hormone?), which could result in being taken advantage of (in any kind of relationship).
For you animal lovers out there, oxytocin levels are also increased in people reporting strong bonds between themselves and their dogs. Annnnnd oxytocin is released when petting animals!
Scientists studying abuse and childhood neglect found that adults that were raised in orphanages or abused during childhood have lower oxytocin levels. They (and I) believe that the early mother-baby relationship is crucial to oxytocin response and human interaction later in life (thanks for all the oxytocin, Mom!).
Oxytocin also promotes social recognition. In rodents, the ability to recognize and process odors of friends and enemies is enhanced by oxytocin. In humans, it helps us remember and recognize faces (way less cool, but hey, probably way more pleasant!). This aspect of oxytocin is crucial to creating and maintaining friendships and relationships. Oxytocin also regulates social memories, displays of friendly as well as aggressive behaviors, and by reducing stress hormones, allows us to trust the faces we see frequently.
While this is awesome, and a great benefit of oxytocin, we need to be careful. These effects cause us to trust people more readily (on oxytocin, study participants will give strangers more money - generosity hormone?), which could result in being taken advantage of (in any kind of relationship).
For you animal lovers out there, oxytocin levels are also increased in people reporting strong bonds between themselves and their dogs. Annnnnd oxytocin is released when petting animals!
2. Oxytocin reduces anxiety, fear and stress
When stimulated by positive social interactions (like hugs, hand-holding, cuddling, or smiles), oxytocin calms down the amygdala, reducing fear and anxiety and creating emotional connections. So if you find yourself in a stressful social situation, oxytocin might help you out and calm your nerves. Oxytocin has also been found to reduce levels of cortisol and ACTH - hormones associated with stress.
3. Wound healing and oxytocin.
Cortisol
inhibits wound healing, and because oxytocin
lowers cortisol levels, it may improve wound healing and inflammation. There were a couple of animal studies that showed that paired animals or animals given oxytocin had improved wound healing. And in humans, pain perception is decreased in people with higher oxytocin levels! This effect of oxytocin may be able
to explain the health benefits of certain therapies such as massage,
aromatherapy, art therapy, and meditation!
4. Love, sex, relationships, & oxytocin. (Why I am posting this on Valentine's Day)
 |
| I'm pretty sure my oxytocin levels spiked when I saw this! |
Like I said before, this aspect of oxytocin is why I became obsessed. Here is a bit of the Valentine's Day appropriate side of oxytocin...
Love: Animal studies of oxytocin are often done on vole rats - monogamous rats that form long-term bonds and are bi-parental (AKA rats that make bonds the same way we do!). Giving vole rats oxytocin enhanced bonds between the vole rat couples, and giving vole rats oxytocin antagonists disrupted those bonds. One of my oxytocin bloggers (yeah, I have those) wonder if people who cheat on their partners have lower levels of oxytocin than the strictly monogamous... hm...
Oxytocin is partially in charge of partner preference (by way of odor in animals or facial recognition in us), and increases during intense romantic attachment. The "euphoric" feeling of a new relationship is related to higher oxytocin levels (higher than longer relationships in fact). But as the relationship continues every touch, kiss, caress, or sexual experience with someone releases some oxytocin, enhancing trust and increasing the subconscious bond between the two people involved. I think that oxytocin is a key to maintaining a successful relationship by reliving that "euphoria" of a new relationship.
Oxytocin is also released during relationship problems and when relationships end. I like to think of it as craving for something you can no longer have. There is a downside to everything, even oxytocin. But cuddling with a pet, dancing, painting, getting a massage, or getting support from friends (oxytocin releasing activities!) can help alleviate those cravings and partially "cure" the break-up blues!
Sex: The biggest rush of oxytocin is released during arousal in men and women, peaking at orgasm. Levels go back to pre-arousal levels about thirty minutes later. This hit of oxytocin is akin to a high from ecstacy. In fact, oxytocin activates the same (dopamine) receptors that addictive drugs do, encouraging us to go back for more!
In male animals, oxytocin increases number of erections (only if testosterone is also present) and decreases time between "mountings." However, at very high levels, the opposite occurs and the male exhibits "sexual satiety" - increased non-sexual attention to the female (post-coital cuddling!).
Women vs. Men: Women have more oxytocin receptors in their body, and express more oxytocin than men (gives us those fab maternal instincts). Also, oxytocin gene promotors contain estrogen response elements so that estrogen actively encourages oxytocin to hang around in our (female) bodies. I like to think this is why women tend to become more attached to their partners during new relationships than men. I also think it can explain some discrepancies between the way males and females act in relationships and during partner bonding... (I could go on and on about this...)
I have a ton of other theories about how the Valentiney actions of oxytocin explain the relationships I have been in or relationships I have heard about from friends. Because I don't have time, many of you have heard them, and my theories are just theories, I'll stop there with this topic...
5. Oxytocin as a cure.
Patients with schizophrenia have low oxytocin levels in their cerebrospinal fluid (CSF), and scientists think that their dysfunction in gaze and facial emotion processing is related to low oxytocin levels. Animals treated with PCP have similar behavior to schizophrenics, and oxytocin restored their social behavior.
Depression, post-traumatic stress disorder, and OCD also seem to be related to low oxytocin levels. SSRIs (antidepressants) were found to cause a short-term increase in oxytocin in rats. Maybe oxytocin can treat depression?
Oxytocin also might decrease blood pressure, reduce body salt content, and act as a pain-killer. Studies are currently being done on the possible uses of oxytocin for fibromyalgia for pain.
Oxytocin is also being tested as a treatment for sexual dysfunction in both men and women.
Children with autism, a developmental disorder characterized by decreased social and communication skills, have lower oxytocin levels and higher oxytocin precursor levels. Maybe an enzyme that makes oxytocin is defective? Children with autism are also more likely to have a certain haplotype of oxytocin receptor. In a small study of 15 adults with autism or Aspberger's, IV oxytocin improved social recognition and speech comprehension, and reduced repetitive behavior in autistic patients. Obviously more research should be done, but it seems that oxytocin is somehow involved in autism, and has the potential to be an amazing treatment.
CONCLUSION:
To sum everything up, oxytocin does a lot of stuff and is super duper awesome and obsession-worthy. I hope you learned a thing or five, and that you now find oxytocin as neat as I do! Feel free to comment with questions or arguments or theories, and I will keep my readers (you) posted on new oxytocin news as I hear it.
Sources: (I love having access to Journals!)
1.) www.oxytocincentral.com
2.) Waguih, W. I., Kahloon, M., Fakhry, Hala. (2011). Oxytocin role in enhancing well-being: A literature review. Journal of Affective Disorders, 130, 1-9.
3.) Heon-Jin, L. Macbeth, A.H., Pagani, J.H., Young, W.S. (2009) Oxytocin: The great facilitator of life. Progress in Neurobiology, 88, 127-151.
Great post! Couldn't resist taking a peak when you posted the link, haha.
ReplyDeleteHere's my question though -- do you think being conscious of oxytocin production and it's effect on us can ultimately impact it's effectiveness? Or is it more of a "your body does it's job no matter what" kind of thing?
I don't think that understanding oxytocin will change how much is released. However, by understanding why you may be feeling the way you feel, you can better control your emotions and oxytocin-related responses. Also, you can chose to use oxytocin to your advantage by taking part oxytocin releasing activities.
DeleteUpdate! In a lecture on pain today, the professor discussed oxytocin! Mice that were isolated in a cage developed depressive-like behavior and stress molecules after nerve injury. Mice with IV oxytocin and mice in social cages showed less depressive behavior and had lower levels of stress molecules.
DeleteOxytocin can lower pain! Maybe kissing a boo-boo really does make it better!