Monogamy in a bottle...at least for voles

Jigyasa Jyotika/ The Daily Cardinal

Introducing a love potion designed to instantly stop and even prevent your spouse from cheating on you!

If changing a callous Casanova to a faithful lover sounds like something only Shakespeare's Puck can do, it may be time to think again. Or maybe Shakespeare was just 400-odd years ahead of his time when he wrote A Midsummer Night's Dream.""

The ""Puck"" is actually a pack of Pucks led by Larry Young, a neuroscientist at Emory University. The Casanova undergoing ""quick fix moral upgradation"" is a small and furry relative of the mouse - the vole. Or rather, the promiscuous variety of the vole.

Voles belong to one of two closely related species: the promiscuous, philandering type or the monogamous, marrying type. The two species also differ in how social they are and how parental they become after having children.

While members of the monogamous variety are highly social and huddle together, members of the promiscuous variety are isolated and aggressive to the point of earning themselves a reputation. Paternal care also seems to correspond with monogamy - male voles of the monogamous kind devote as much time to the babies as the female. Babies of promiscuous voles, however, are reared only by the female partner.

Recently, the Puck pack at Emory reported they had brought the promiscuous variety around, making them monogamous by manipulating a single gene. Literature in the field of neuroendocrinology (the study of how hormones act on the brain to influence behaviors), indicated that sex hormones influenced these behaviors.

Specifically, two hormones - vasopressin (in males) and oxytocin (in females) - were known to be responsible for forming bonds and attachment within couples and between mothers and infants in some mammalian species.

Research into the molecular basis of pair-bonding in voles started when the same hormones were tested for their involvement in pair-bond formation in voles. When male voles were injected with the vasopressin hormone, they formed stable pair-bonds with females even without mating with them. Blocking the action of vasopressin in male voles that hadn't mated, on the other hand, prevented them from forming a pair-bond after mating, confirming that vasopressin plays a key role in pair-bond formation. Regulating oxytocin in females that hadn't yet mated produced the same results. Previous literature also indicated that vasopressin is responsible for social recognition of individuals in voles.

All this is fine, except that promiscuous male voles also have vasopressin in their systems. Investigating this paradox led researchers to discover differences in brain regions and in vasopressin receptor levels between monogamous and promiscuous voles.

Monogamous voles have their vasopressin receptors located in the ""pleasure centers"" of their brains - the same pleasure center the good feeling after eating chocolate or having sex comes from. So it was postulated, for this species, that mating with an individual recognized vole and feeling good about the sex happens in a coordinated fashion, forming an association between that particular partner and the mating-related good feeling.

In all subsequent matings, perhaps the social memory of the partner and the memory of the good feeling makes, the vole perceives the partner as the cause of the pleasure and this association is what makes these voles stick to the same partner.

What the Emory Puck pack did in a recent study, published in Nature, was take the gene for the vasopressin receptor from the monogamous vole and inject it into the brains of promiscuous voles, such that the gene now produces the same levels of the receptor as found in the monogamous vole.

The result? The erstwhile promiscuous male voles underwent a radical transformation into males that exhibited nothing short of complete monogamy. With this, the former philanderers suddenly started spending significantly higher amounts of time huddling with their partners. Furthermore, when the researchers inactivated the vasopressin receptor gene injected into the promiscuous species, the voles resorted to their old habits and all trace of faithfulness instantly vanished.

But what does any of this have to do with humans? Studies in humans involving fMRI (fluorescent Magnetic Resonance Imaging) have shown that when people see pictures of their lovers, blood flow to the pleasure and addiction centers increase. Many of these regions have lots of vasopressin, oxytocin and their receptors. A similar fMRI pattern emerges when mothers are shown pictures of their own children.

Neuroscientist Thomas Insel, also at Emory University, is investigating pair bonding in voles and the biochemistry behind their love in an effort to search for a link between studies on these behaviors in voles and social disorders in humans like autism and schizophrenia, both of which are characterized by isolation and lack of attachment.

So, lessons learned from a small furry rodent indicate researchers may have found a single key gene responsible for fidelity and community, and in fact created evolution and history in the laboratory.

If chemistry really is behind it all, the science of love may simply be the hottest chemical reaction around.