February’s Molecule of the Month


By Marcus Taylor

There are many mysteries in our Universe that are yet to be solved: how did life begin, what came before the Big Bang, are we alone in the Universe? These are all big questions that fall into the domain of science and which scientists of the past, present and future are trying to solve.

However, there are other mysteries which science is only just beginning to explore and which are still deeply rooted in philosophy. Consciousness is one example, and whilst science is slowly starting to understand how consciousness might form, the ideas of ego, inner-self and even the soul are still deeply held beliefs and explanations. Another of these mysteries is that of love. The concept of love has been around for thousands of years and is the basis for many superstitions, folklore and beliefs.

For the Romans, love was distributed by Cupid, the God of desire, love, attraction and affection. Often portrayed as a chubby boy, Cupid was armed with a bow and arrow. Anyone struck by one of these arrows was said to be filled with uncontrollable desire.

At times it would be hard to tell apart the sweet God of Love from a relentless hunting machine that will stop at nothing until that love dart hits its mark.

Put it this way – If Shakespeare had written the Terminator I think Arnie would have had wings and a bow.

Forward to the present day and anyone who has read and watched Harry Potter and the Half-Blood Prince will be well aware of love potions and the effect one has on poor Ron. But as the story cautions us, such a potion cannot create true love, only an intense obsession.  The idea of a love potion is nothing new though and throughout history people have claimed to have made love potions or spells.

Before you panic that this month is going to be a mystical, magical discussion on what is love, then don’t worry, we have no intention of going down this deep and philosophical route. However, we can provide some chemical explanation for that feeling of love, romance or pleasure.

If we were building a robot and wanted it to experience feelings of love and the warm feelings of social interaction, then we would definitely need to consider this month’s molecule; oxytocin.

But let’s be clear, it is a lot more complicated. Simply giving someone a vial of oxytocin to drink does not make a love potion.

Oxytocin is a molecule known as a peptide hormone. A peptide is a chain small of molecules, known as amino acids, which are connected together with a special kind of chemical bond known as a peptide bond. Oxytocin is made up of 9 amino acids joined together, the structure of which is shown below. Its structure contains a type of bond commonly found in proteins called a disulfide bond – a connection between two atoms of sulfur. This bond is important for determining the shape of certain proteins.

At 135 atoms, oxytocin is a fairly decent size molecule, and a strain on the illustrator’s hand! The two yellow atoms at the back show the sulfur-sulfur bond.

As well as being a peptide, this molecule is also a hormone. These are molecules that act as messengers throughout our body – a kind of internal post system that delivers messages and signals to different parts of our bodies to get them to do something. This could affect your growth, mood, the way you energy from food (metabolism) and even your sleeping and waking cycle.

As a hormone, oxytocin is produced in a small part of the brain known as the hypothalamus (hi-po-thal-a-muss) and released by a nearby gland called the pituitary (pit-chew-it-tree) gland.

This leads us to a very important and exciting question. If oxytocin is a hormone, and if hormones are chemical messengers that tell the body to react or control an important function, then what message does oxytocin deliver to our body? Well, the fact this molecule is sometimes known as the “love hormone” is a big clue! However, oxytocin has been found to significantly affect all aspects of our lives.

The amount of oxytocin in our bodies is usually higher for women than men. This is not surprising as the molecule plays a big part in pregnant women who are close to giving birth. It has been found that oxytocin is responsible for the contractions during the later stages of labour. In fact, the name oxytocin comes from the ancient Greek language and means “quick birth”. In addition, one of the medical uses of oxytocin is to help induce labour.

The role oxytocin plays in social interactions, including those of love, is what has made the molecule popular amongst the general public. The connection between this molecule and love (or to keep in more scientific – social interactions) was noted in a study done during the 1990s. Research showed that prairie voles (a small rodent found in North America) who mate for life with only one other vole, had higher levels of oxytocin compared with other species of vole who were happy to have lots of mates!

Celebrating St Volentine’s Day.

Further research has shown that positive social interactions such as cuddling or hugging raise the levels of oxytocin in our blood. This is also true when new born babies look into the eyes of their mothers and vice-versa. All of this helps in the bonding process and the feelings of care, warmth and love we have towards family and friends.

The relationship between levels of oxytocin and social interactions even extends to pets. Studies have shown that oxytocin levels also increase in both dogs and humans during petting and eye contact, strengthening the bond with man’s best friend. Despite this, we strongly recommend you don’t go around staring into the eyes of wild or unfamiliar pets – it could be seen as an act of aggression.

Don’t stare into its eyes – it might adorable you to death.

Oxytocin is not all about happiness and positivity, and is widely believed to help manage fear and anxiety. One study found that oxytocin reduced fear, but also helped people to identify facial expressions of disgust. There is also evidence that oxytocin can make social memories more, well, memorable. However, this is not always a good thing especially as oxytocin seems better at making bad memories stronger. This can have a significant impact on stress levels, anxiety and depression.

We said earlier that a vial of oxytocin does not make a love potion. So what does happen when living organisms are given an increase in oxytocin? In one study, a group of men in faithful relationships were given some oxytocin through a nasal spray (basically up their nose!). When these men were introduced to attractive women, they increased the distance between themselves and the woman. It appears that the oxytocin caused an increased feeling of faithfulness. When nasal sprays of oxytocin were given to the fathers of young babies, the fathers were found to play more closely with their new born baby, again strengthening the bond between them.

To describe love as being purely chemical and related to one molecule called oxytocin is much too simple. There is no doubt love is much more complex involving our emotions, mental state and psychology. Even on a chemical level, oxytocin is not the only molecule connected to love and similar feelings.

However, what is certain is that the release of oxytocin during social interactions, mother and baby eye-contact and even petting dogs helps to increase and strengthen the bond felt between the two. Oxytocin is by no means unique to humans either, with dogs, voles and other animals also showing increased levels of oxytocin when in committed relationships or during strong social interactions.

However you choose to describe love and whatever you believe it to be, it is impossible to artificially create. No magic arrows, potions or vials of oxytocin are going to make two people fall in love. Nevertheless, the role that molecules can play in our feelings, emotions and psychology is important and an area of exciting research.

As for our robot… it has unfortunately yet to find true love.

5 thoughts on “February’s Molecule of the Month

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  1. Is oxytocin used in any medication? Could it be used, for example, in helping to treat post natal depression, or are there potential side effects?

    1. It is used medically for a few things – it can be used to induce labour and with a few childbirth associated things like lactation and breast feeding.

      I’ll have a look about for some sources for you and see if I can find any links to post natal depression… Bear with.

      What a good question. 😁 Thanks!

  2. Is oxytocin used in any form of medication? For example, could it be used to help treat post natal depression or are there potential side effects (or it just wouldn’t work at all)?

  3. There is preliminary and early-stage studies looking at the use of oxytocin for treating anxiety. Whilst anxiety and depression are often associated they are very distinct conditions. In terms of a medicine, it may not be the oxytocin itself that is directly administered into the body, but instead an alternative drug that increases the production of oxytocin. Research has shown that oxytocin has potential anti-depressant effects (at least in animals), but more detailed studies are required.

    Hope that provides some additional information 🙂

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