Oxytocin as an Anxiolytic

Did anyone try using probiotics to reduce stress? Did it work? Yes? No? Well, I have another suggestion.

Try having sex.

Now, I know some of you will probably think this seems obvious. Don’t we usually feel really good after sex? I am going to ask, however, that we ignore the notion of the post-coital glow, runner’s high, or whatever it is you get after copulation. Let’s cool those jets and look at two studies involving the anxiolytic effects of oxytocin in rat mating.

First, let’s give a preface that is kind of given by both of these studies. Oxytocin is involved in a lot of good stuff psychologically. Oxytocin has been shown to reduce stressful behavior in animals, and medical researchers are even working on using it to treat anxiety in humans. It is also involved in prosocial behaviors. Basically, this is a peptide involved in being trusting, friendly, cuddly and calm or open.

Now, let’s look at how the males do with sex. Waldherr and Neumann demonstrated that mating with a receptive female led male mice to exhibit less stress behavior and more risk-taking associated behavior (2007). They ran a number of different tests. They found that males who were mated to females explored with open arms and exhibited more risk taking behaviors even 6 hours later. They also monitored the periventricular nucleus of conscious rats exposed to receptive (primed) and non-receptive (non-primed) females. They were able to set up a partition allowing visual, auditory and olfactory, but not physical contact between the male and female. What they found was elevated oxytocin release in males presented with receptive females. When the researchers injected the┬ámales with an oxytocin receptor antagonist (a chemical that blocks oxytocin) the rats ceased to exhibit the open behavior, demonstrating that it was, in fact, the oxytocin that had had the anxiolytic effect.

Nyuyki and colleagues looked at oxytocin and mating in female mice (2011). What they found was that females needed to control or pace the situation in order to have positive effects (the major one being oxytocin release) from sexual encounters. What they did was place primed or unprimed females in one of two situations with a male. There was a non-paced arena and a paced one in which a partition allowed the smaller female to hide from the male. The behavioral tests they ran were quite similar to the previous test. The results indicated that steroidally primed females, in a paced sexual environment were able to achieve the anxiolytic release of oxytocin. However, those placed in non-paced situations quickly lost the effect of priming, and did not achieve the oxytocin levels the paced females did. Basically, the female mouse needed to be ready to get the beneficial effects of sex.

These studies suggest that, at least in rats, sex leads to a stress-relieving rush of oxytocin from the periventricular nucleus in both sexes. However, for the female to get the proper effect, the copulation must be done on her terms, at her pace.

Now I’m wondering if this may be related to that feeling of ennui some guys get post-climax. Perhaps I’ll look into that for next week…

… either that or chocolate.

Nyuyki KD, Waldherr M, Baeuml S, Neumann ID (2011) Yes, I Am Ready Now: Differential Effects of Paced versus Unpaced Mating on Anxiety and Central Oxytocin Release in Female Rats. PLoS ONE 6(8): e23599. doi:10.1371/journal.pone.0023599

Waldherr M, Neumann ID (2007) Centrally released oxytocin mediates mating-induced anxiolysis in male rats. PNAS 104(42): 16681-16684.