Why some people cannot suppress the urge to urinate at night has long baffled scientists. Now,a new research has found that the body’s internal clock controls the production of a key protein that regulates the bladder’s capacity to hold urine over night.
The findings,published in journal Nature Communications,may someday yield new therapies to help children who involuntarily wet the bed or adults who frequently wake up at night to urinate,the researchers said.
“This research explains why healthy people do not urinate during sleep,from the standpoint of bladder function,” study co-author Dr Akihiro Kanematsu,an urologist at the Hyogo College of Medicine in Japan,told LiveScience.
By targeting the protein,called connexin43,researchers may be able to induce the correct amount of the protein at the right times,said Andrea Meredith of University of Maryland who was not involved in the study.
Past research has shown that mice with an increased amount of connexin43 have a lower functional bladder capacity — that is,their bladders require less liquid before it
triggers the need to urinate.
It was known that humans and other animals have day-night differences in functional bladder capacity,but it’s not clear if these differences are due to light or if they are governed by an intrinsic circadian (daily) rhythm.
To find out,the researchers needed to determine how much and how often mice urinate throughout the day. To measure that they developed a device that constantly moved a filter paper beneath a mouse cage to capture the urine.
It’s found the mice’s day-night urination differences exist even when they are in 24-hour darkness. Moreover,this normal urination pattern was lost in mice with defective biological clocks,showing,for the first time,that urination is an intrinsic circadian rhythm,the researchers said.
The researchers also found that mice with an abnormal connexin43gene,which produces the connexin43 protein,urinate less frequently than normal mice.
And when they looked at the bladder muscle cells of normal mice,they found that the expression of the connexin43 gene oscillates throughout the day and is governed by a certain circadian clock molecule.