Ghrelin receptor identified as key to easing constipation in Parkinson’s patients

Considered the natural "hunger hormone", Ghrelin could be the key to preventing debilitating chronic constipation experienced by people living with Parkinson's disease, University of Queensland researchers have found.

Associate Professor Sebastian Furness from the UQ School of Biomedical Sciences said the team discovered the body's receptor for Ghrelin had a critical role in the normal function of the spinal defecation centre – an area of the body in the lower spinal cord that controls bowel movements.

The 'reward molecule' dopamine is a neurotransmitter and chemical messenger responsible for controlling bowel movements, but we've shown that to work properly in this setting it needs a partner, and that partner is the receptor for Ghrelin.

We're translating this knowledge about normal physiology into a major step towards improving the quality of life for people with Parkinson's disease, a neurodegenerative disorder that causes chronic constipation in up to 90 per cent of patients.

Chronic constipation is debilitating and is one of the biggest factors for reduction in the quality of life for people with Parkinson's because it is poorly managed by current approaches."

Dr. Sebastian Furness, Associate Professor, UQ School of Biomedical Sciences

Dr. Furness said Parkinson's disease can cause changes in the spinal control pathway for defecation, which is why constipation is a common problem for patients.

"While Parkinson's affects dopamine-carrying neurons in the brain, the dopamine-carrying neurons responsible for defecation are not, and our research suggests targeting the Ghrelin receptor could overcome the changes in the spinal defecation control pathway," Dr Furness said.

"We will now explore how medicines targeting the Ghrelin receptor may help coordinate voluntary defecation and alleviate chronic constipation for people with Parkinson's disease.

"This discovery might allow us to substantially improve the lives for people living with Parkinson's Disease.

"Our work has led to a new explanation for chronic constipation in Parkinson's that is viewed as so important the U.S. Department of Defense has awarded us $3 million to pursue the idea."

The study was funded by a National Health and Medical Research Council (NHMRC) Ideas grant and carried out in collaboration with the Florey Institute for Neuroscience and Mental Health, University of Melbourne, and Monash Institute of Pharmaceutical Sciences.

The research is published in Molecular Cell.