NZ brain study targets cannabis-like substance

University of Auckland researchers will attempt to unravel the complex processes involved in the release of dopamine. Photo / 123RF

A recently-discovered cannabis-like substance naturally produced by our brains could play a role in treating Parkinson's disease.

University of Auckland researchers will attempt to unravel the complex processes involved in the release of dopamine - and how what are called endocannabinoids might influence them.

Dopamine is a chemical transmitter that underlies many of our basic behaviours, including movement, but much about the mechanism that determines the timing and size of its release remains unknown.

This has hampered scientists trying to make breakthroughs in diseases where dopamine is involved, such as Parkinson's disease, which today affects around 13,000 Kiwis.

But Dr Peter Freestone, of the university's Department of Physiology, hopes there will be potential in a unique encannabinoid, called NADA, which can alter the activity of dopamine-producing cells.

NADA was exciting to researchers as it shared a common biosynthesis pathway with dopamine, making it important to the pathophysiology of Parkinson's disease.

Previous work had already indicated that endocannibanoids should control the electrical activity of dopamine-producing neurons.

"If [NADA] is controlling the electrical activity, it should also be controlling the amount and timing of the dopamine that's released in the brain - that's where this new project comes in and we now want to take it to that next level."

The two-year, $150,000 study to be led by Freestone and colleague Professor Janusz Lipski will draw upon a combination of electrochemistry methods that detect dopamine and optogenetic methods that stimulate specific cell types.

"We can actually use light to activate specific cells that we choose ... and that means we can study these networks in much greater detail."

They expect the work - to be carried out on range of experimental models, from living brain slices to freely moving animals - will ultimately reveal how NADA controls dopamine levels and related movement processes, potentially leading to new therapeutic strategies for diseases like Parkinson's disease.

"This new study is going to be filling in the gaps to see whether we can go forward with a clinical study - we'll know whether endocannibanoids regulate dopamine and whether that's something we could target with drugs or treatments in the future," Freestone said.

"I'm hoping... but then previous work suggests it should be at least an option."

The study is supported by the Auckland Medical Research Foundation.