A sigh of relief: peptide that controls sighs found

It is not only relief, but often sadness or exhaustion may also cause sighing - a long breath. And, of course, there are also sighs without any of these - a spontaneous sigh that helps to reinflate the alveoli of your lungs. So what is the most proximal cause of sighing?

The center in the brain that controls breathing (retrotrapezoid nucleus) sends signals to the respiratory rhythm generator in the brain (preBötzinger Complex). These signals consist of two peptides: neuromedin B and gastrin-releasing peptide. A shot of these peptides elicits sighing. Blocking either of these peptides reduces sighing and blocking both peptides eliminates it altogether.

Whether it is relief from tension, emotions, tiredness or any other distal causes, this is the peptide that ultimately sets off a sigh.

A report in the recent issue of  Nature - 8th February 2016 - looks into the peptidergic control circuit for sighing.