Julie Kanya explores the versatile love hormone oxytocin

The Beatles once wisely said that ‘All you need is love’. As decades passed and science progressed, humans have actually managed to find the chemical responsible for this unparalleled feeling of contentment, fulfillment, and all-around stark attachment: a tiny nonapeptide (a peptide formed by 9 amino acids) that goes by the name of oxytocin. Its Greek name actually means ‘quick birth’, accurately reflecting one of its main effects – inducing contractions during labour. But that’s just the tip of the iceberg of functions, many of which are still lying beneath sea-level, simply waiting to be discovered.

In 1906, British pharmacologist Sir Henry Hallett Dale uncovered the function that coined its descriptive denomination and its milk ejection property was outlined both by Ott and Scott in 1910 and by Schafer and Mackenzie in 1911. Made by magnocellular neurons in the hypothalamus and secreted by the posterior pituitary alongside vasopressin in order to act at a distance, oxytocin was the first polypeptide hormone to be sequenced and synthesized. For this break-through endeavor, Vincent du Vigneaud was rewarded with a Nobel Prize in Chemistry in 1955.

But what exactly makes oxytocin so eclectic? Its well-established roles in sexual reproduction (namely distension of the cervix and uterus during labour and stimulation of the nipples, thus facilitating breastfeeding) have been settled for nearly a century, yet recent research shows that there’s far more than meets the untrained eye. Apparently, this minute hormone (cysteine-tyrosine-isoleucine-glutamine-asparagine-cysteine-proline-leucine-glycine-amine, to be more specific) is tightly connected to various behaviors, including orgasm, social recognition and pair bonding. The first MRI scan of a female brain during climax clearly shows that oxytocin literally floods the cerebrum in an explosive sequence[1], distinctly suggesting that this ‘cuddle hormone’ might play a key part in the overarching concept defined as ‘love’. Moreover, the inability to secrete oxytocin has been linked to a wide variety of sociopathic behaviours, from general narcissism to full-fledged psychopathies.

Nevertheless, its clinical applications are trying to bridge the gap between proper public etiquette and pervasive developmental disorders. For instance, when employed in the treatment of autism, it quenches repetitive drives and increases retention of affective speech. More recently, it has been proved that intranasal administration of oxytocin greatly improves emotion recognition in young people diagnosed with autistic spectrum disorders[2], consequently proving that it also plays a pivotal part in increasing trust and reducing fear.

All things considered, ‘the love hormone’ is as heterogeneous as all of the reactions it mediates. From maternal bonding to wound healing and from romantic devotion to overcoming substance withdrawal, oxytocin seems to make its tiny presence known in many aspects of life. Want to experience a sudden surge of it? There’s nothing simpler than giving your friend a proper hug. Not just a pat on the back and a peck on the cheek, but a lengthy embrace, just as honest as childhood encounters once were. Feeling better? Maybe all we do need is love. And just a pinch of oxytocin, for the seasoning.

 

Julie Kanya

 

Image by George Eastman House