Thursday, December 22, 2011

Single nucleotide change in oxytocin receptor gene decreases stress relief by social support.

In recent years, the human oxytocin system has been increasingly studied as essential to our prosocial behavior and also buffering stress. One single nucleotide variation in the oxytocin receptor (OXTR) gene named rs53576 (G/A) involves switching between the G and A nucleotides. THe A allel of rs5376 has been associated with lower empathy, reduced reward dependence, lower optimism and self-esteem, and negative affect. Now Chen et al. find a further correlation; individuals with two copies of AA do not show lower cortisol responses to stress after social support. Here is their abstract:

The neuropeptide oxytocin has played an essential role in the regulation of social behavior and attachment throughout mammalian evolution. Because recent studies in humans have shown that oxytocin administration reduces stress responses and increases prosocial behavior, we investigated whether a common single nucleotide polymorphism (rs53576) in the oxytocin receptor gene (OXTR) might interact with stress-protective effects of social support. Salivary cortisol samples and subjective stress ratings were obtained from 194 healthy male participants before, during, and after a standardized psychosocial laboratory stress procedure. Participants were randomly assigned either to prepare alone or to receive social support from their female partner or close female friend while preparing for the stressful task. Differential stress responses between the genotype groups were observed depending on the presence or absence of social support. Only individuals with one or two copies of the G allele of rs53576 showed lower cortisol responses to stress after social support, compared with individuals with the same genotype receiving no social support. These results indicate that genetic variation of the oxytocin system modulates the effectiveness of positive social interaction as a protective buffer against a stressful experience.

4 comments:

Carolyn Hastie said...

Very interesting Deric. So what influences whether someone has the G allele of rs53576? What switches that on or off? and when? Do you have any idea? So fascinating!!

Deric said...

An egg cell and a sperm cell will each have one allele or the other, what happens depends on the match at fertilization.

Carolyn Hastie said...

Sorry, I didn't make my question clear. Given that the environment is thought to influence or even dictate (epigenetics) which allele is expressed during development of the ovum and sperm and again at fertilisation, I was wondering if you had any knowledge of what causes that particular allele to be expressed or not

Deric said...

Sorry for delay…family, holidays, …. the short answer is that I don' have any knowledge of the epigenetics of the alleles in question. But it should be possible to find the info on the web fairly easily.

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