Tuesday, September 16, 2014
Experiments on rats given a potent cannabinoid have shown the drug stimulates the growth of new brain cells. Canadian researchers found that the drug caused neurons to regenerate in the hippocampus, an area that controls mood and emotions, after one month of treatment.
Its effect was similar to that of the antidepressant drug Prozac, which also stimulates nerve growth in the hippocampus. The rats were less anxious and more willing to eat in a novel environment that would normally make them fearful.
Most drugs, including alcohol, heroin, cocaine and nicotine, have been shown to destroy nerve cells in the hippocampus, the researchers from the University of Saskatchewan, Canada, say. "The present study suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic administration," they write in the Journal of Clinical Investigation.
The finding runs counter to previous research highlighting the risks of cannabis use, including a heightened degree of psychosis in vulnerable users, and an increased risk of lung cancer similar to that in tobacco smokers. The authors say regular cannabis users are known to suffer acute memory impairment, as well as dependency and withdrawal symptoms.
The new research suggests that the size of the dose may be crucial. The results showed that regular injections of high, but not low, doses of the artificial cannabinoid HU210 were associated with anti-anxiety and antidepressive effects.
"These complicated effects of high and low doses of acute and chronic exposure to cannabinoids may explain the seemingly conflicting results observed in clinical studies regarding the effects of cannabinoid on anxiety and depression," the scientists say.
The study emerged from the recent discovery that, unlike other parts of the brain, the hippocampus can generate neurons throughout the lifespan of mammals, including humans.
Natural selection has conserved cannabinoid receptors in animals that have been separated by evolution for 500 million years, suggesting they have an important biological role. Cannabinoids appear to alter the effects of pain, nausea, tumours, sclerosis and other disorders in both animals and humans, the team says.
The experiment involved giving rats regular injections of HU210 for a month. At the end of this time, hungry animals showed significantly less reluctance to eat in a novel environment. Rats are normally neophobic - wary of new situations.
The New South Wales Government has announced a clinical trial of the medical use of marijuana, making its legal use one step closer in the state.
A working group has been formed to set up the trial, which will look at ways to address issues of supply and distribution, and report back by the end of the year.
The Government is also moving to formalise police guidelines so that people who possess small amounts of cannabis will not be charged if their name is on a register of terminally ill patients.
NSW Premier Mike Baird has told Parliament he was touched by the plight of terminally ill Tamworth man Daniel Haslam.
"Why not take a stance to say to the rest of the country, this matters. It's time we did something about it," he said.
"So I say at the same time, we want to give the terminally ill and those around them, their carers, their family, greater peace of mind. We also want to ensure that carers aren't forced to watch their loved ones suffer when their pain can be alleviated."
Mr Haslam's mother Lucy has been leading a campaign to have medicinal cannabis legalised for her son.
Daniel Haslam was diagnosed with bowel cancer and the 24-year-old found cannabis offered some relief to the harsh effects of chemotherapy.
Mrs Haslam said she was elated when the Premier told her of the Government's decision this morning.
"I think I gave him a big hug and a kiss. He's a very kind, caring man, you know he's a dad," she said.
"I think he probably knows as any parent the horrible feeling of watching your child suffer and feeling powerless. He can empathise with that I think."
Mr Baird said NSW is leading the way on an issue that should now be on the national agenda.
"That's my call to this house today and every stakeholder that wants to play, every member that wants to play a role, every party that wants to play a role, it's time that we got this done," he said.
"The country has waited too long, this state has waited too long."
In the interim, the Government is also formalising police guidelines to ensure registered terminally ill patients will not be charged for possessing small amounts of cannabis.
Nationals MP Kevin Anderson had been drafting a private members bill to legalise medical marijuana.
He said he now hopes the State Government will be able to take a firm plan on the issue to the next state election.
"I would sincerely hope so. I think that here we are six months on from when we first started to talk about this and we now have a rock solid government position," he said.
"There are no other jurisdictions across Australia that are this far advanced in terms of doing what this government is doing."
Source ; ABC NEWS