“Poetry it is not. Nor is it particularly romantic. But reducing love to its component parts helps us to understand human sexuality, and may lead to drugs that enhance or diminish our love for another.” Dr. Larry Young of the Emory University School of Medicine isn’t talking about aphrodisiacs–substances that can increase libido. He’s talking about drugs that can affect our desire to spend the rest of our lives with someone. That’s crazy talk, right? Well, guess what. There’s already a proven love potion for voles, and scientists are working to develop one for humans, too.
1. How to make a certain person be attracted to you:
Several products claim to increase your appeal to the opposite sex. In fact, here’s a link to five that you can already buy. However, as the author of that list acknowledges, there’s no way to separate the effects of the substances from the effects of the extra confidence the substance users feel. More importantly, even if effective, these products merely increase someone’s sexual attraction to you–they don’t presume to be able to help you find your mate.
More compelling are the custom “biologically effective perfumes” that link preference in body odor to one’s own genetic variants of the MHC (major histocompatibility complex) immune system genes. The guys behind this idea are thinking something along the lines of a custom perfume that mimics your own body odor, allowing potential mates to smell you better and thus allowing you to more effectively attract the ones you would naturally attract anyway (in fact, researchers have already shown that this works). Of course, one can also envision a world in which you inconspicuously swab your crush’s pits and send the sample to a custom synthesis lab to get a perfume scent you know he’d be attracted to. Unethical? Yes. Unsustainable? Yes. But at least when he bails you’ll have an answer to that inevitable question, “Why doesn’t he love me anymore?” It’s because you stopped wearing your veil of lies.
On a side note, a woman’s odor preferences can actually change when she uses oral contraceptives, according to this study. Scary that messing with hormones can [theoretically] mess with your choice of a life partner.
2. How to make someone be emotionally available:
Let’s talk about voles.
The prairie vole is as highly social and monogamous or more than any other known mammal. My Neuroscience textbook by Bear, Connors & Paradiso describes these voles as having an “intense period of initial matings,” after which the male and female live together in one nest pretty much forever. These males fiercely defend home and mate, and even participate in child rearing.
Meadow voles, on the other hand, are sluts. Each has a private crib where guests are entertained on a one-night-only basis. Males take no part in parenting, and even the females kick the kids out as soon as they have a nonzero probability of dying immediately.
So what sets these species apart? They are physically and genetically very similar, with one noticeable exception: their brain maps of vasopressin and oxytocin receptors differ significantly. Interestingly, after a meadow vole gives birth, her receptor maps briefly resemble that of a prairie vole, presumably so she can [want to] feed her babies.
If you know what molecular receptors are, skip this paragraph. Receptors are big molecules with specific pockets that small signaling molecules (drugs or natural neurotransmitters) can fit in and bind to. I’ll be doing a post on drugs and their natural analogues soon, but for now, all you need to know is that when these signal molecules bind their receptors, the neuron attached to the receptor responds and can pass on the signal to other cells. Stuff just doesn’t get done without sufficient receptors in the proper places, even if you dump a boatload of extra neurotransmitters there.
Vasopressin and oxytocin are peptide hormones that serve as neurotransmitters (chemical signals) in the brain. The former stimulates pair bonding, competitive aggression and paternal activities in males; the latter stimulates maternal instincts, lactation, uterine contractions during birth, and feelings of attachment toward offspring and mate in females. Oxytocin interacts with the reward and reinforcement system driven by the neurotransmitter dopamine. This happens to be the same circuitry that’s affected by nicotine, cocaine and heroin to produce euphoria and addiction.
During the deed, levels of vasopressin in male prairie voles and oxytocin in females increase sharply. However, even the clingy male prairie vole will hit it and quit it if he’s given vasopressin antagonists (which prevent binding of vasopressin to the receptors) prior to copulation. Obversely, if gene therapy is used to put more vasopressin receptors in the brain of the promiscuous male meadow vole, he’ll put a ring on it like any born and bred prairie vole.
Another interesting experiment was this: when vasopressin was given to a male prairie vole while he was exposed to a new female, he quickly became attached to her even though they hadn’t done it yet. Similarly, a female prairie vole whose brain is infused with oxytocin will rapidly form a preference for the nearest male.
This is crazy. This is chemical manipulation of love.
“Psh,” you might say, “but voles don’t feel what I feel for my partner.” While I’m sure there is some truth to this, there are many similarities between vole pair-bonds and those of humans. When a mother looks at pictures of her child, the dopamine-related regions of her brain lights up. This also occurs when people look at photographs of their lovers. And you can’t ignore this fact: For both humans and voles, polymorphisms in the AVPR1A gene are directly responsible for the amount of vasopressin receptors expressed in the brain. The likelihood that a male vole will bond with a female can be accurately predicted from the layout of his avpr1a regulatory region, and differences in human AVPR1A are associated with variations in pair bonding and relationship quality. In fact, Dr. Young’s Nature article describes a recent study showing that “men with a particular AVPR1A variant are twice as likely as men without it to remain unmarried, or when married, twice as likely to report a recent crisis in their marriage.”
We’re moving toward a world in which failure to commit and fear of intimacy are legitimate, treatable genetic disorders. I can hear Beyoncé now: “If you want it then you should’ve got a vasopressin booster.”
What on earth could compel scientists to develop a real love potion? Well, for starters, studies are ongoing in Australia to determine the feasibility of an oxytocin spray as an aid in couples therapy. But marital troubles aren’t the only things that call for chemical intervention. For instance, Japan is currently struggling with an asexual epidemic that has already dramatically reduced its population, and a recent study predicts that its population will decrease another third by 2060. According to a member of the Japan Family Planning Association, the severe lack of dating and sex could result in the “extinction” of the Japanese people. All I’m sayin’ is, I wouldn’t be surprised if the love potion were introduced as a way to save an entire human race. Drastic times call for drastic measures.
So how close are we to developing an effective love potion? Experiments have shown that a nasal squirt of oxytocin makes men more attracted to their partner than to a stranger of the same attractiveness, but take it with a grain of salt because there was a pretty small difference between results from the placebo and oxytocin. I think that in order to have a significant and lasting effect, a “love potion” would have to increase the expression of vasopressin and oxytocin receptors in the brain. This would require gene therapy of the kind that uses viruses to carry the genes to target cells, so it’s still a bit risky. That’s not to say harmless viruses aren’t an appropriate vector for this, and in fact if you’ve read my gene editing post, you know that this technology has been successfully used in humans before to treat several serious diseases. It’s only that, unlike deafness or Bubble-boy disease, “fear of intimacy” is not necessarily worth the risks associated with this therapy right now. Having said that, we’ve got to remember that biotechnology is advancing at a mind-blowing rate and it’s not too far-fetched to predict that someone might start clinical trials for an actual love treatment in the near future. Ethical impediments aside.
Should you freak out? Fortunately, I don’t foresee this kind of treatment ever coming in a DIY kit, so unless you’re dating the Overly Attached Girlfriend, you’re probably safe from being chemically manipulated into falling in love.
If you or a loved one are experiencing fear of intimacy, talk to your doctor to see if the Vasopressin Booster is right for you. Side effects may include: feelings for people, and cancer.
Discussion Topic: How would you feel about dating someone with chemically enhanced emotional availability?