High-dose cannabis stimulates growth of brain cells in rats

Cannabis, the third most popular recreational drug after alcohol and tobacco, yesterday won an unlikely accolade from scientists who said that it could boost brain power.

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.

Life and Style
ebookNow available in paperback
ebooks
ebookA delicious collection of 50 meaty main courses
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
SPONSORED FEATURES

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Recruitment Genius: Sales Executive or Senior Sales Executive - B2B Exhibitions

    £18000 - £30000 per annum: Recruitment Genius: A Sales Executive or Senior Sal...

    Recruitment Genius: Head of Support Services

    £40000 - £55000 per annum: Recruitment Genius: This is an exciting opportunity...

    Recruitment Genius: Warehouse Team Leader

    £22000 per annum: Recruitment Genius: This industry leading company produces h...

    Recruitment Genius: Business Development Manager / Sales - OTE £40,000

    £20000 - £40000 per annum: Recruitment Genius: This IT provider for the educat...

    Day In a Page

    The Silk Roads that trace civilisation: Long before the West rose to power, Asian pathways were connecting peoples and places

    The Silk Roads that trace civilisation

    Long before the West rose to power, Asian pathways were connecting peoples and places
    House of Lords: Outcry as donors, fixers and MPs caught up in expenses scandal are ennobled

    The honours that shame Britain

    Outcry as donors, fixers and MPs caught up in expenses scandal are ennobled
    When it comes to street harassment, we need to talk about race

    'When it comes to street harassment, we need to talk about race'

    Why are black men living the stereotypes and why are we letting them get away with it?
    International Tap Festival: Forget Fred Astaire and Ginger Rogers - this dancing is improvised, spontaneous and rhythmic

    International Tap Festival comes to the UK

    Forget Fred Astaire and Ginger Rogers - this dancing is improvised, spontaneous and rhythmic
    War with Isis: Is Turkey's buffer zone in Syria a matter of self-defence – or just anti-Kurd?

    Turkey's buffer zone in Syria: self-defence – or just anti-Kurd?

    Ankara accused of exacerbating racial division by allowing Turkmen minority to cross the border
    Doris Lessing: Acclaimed novelist was kept under MI5 observation for 18 years, newly released papers show

    'A subversive brothel keeper and Communist'

    Acclaimed novelist Doris Lessing was kept under MI5 observation for 18 years, newly released papers show
    Big Blue Live: BBC's Springwatch offshoot swaps back gardens for California's Monterey Bay

    BBC heads to the Californian coast

    The Big Blue Live crew is preparing for the first of three episodes on Sunday night, filming from boats, planes and an aquarium studio
    Austin Bidwell: The Victorian fraudster who shook the Bank of England with the most daring forgery the world had known

    Victorian fraudster who shook the Bank of England

    Conman Austin Bidwell. was a heartless cad who carried out the most daring forgery the world had known
    Car hacking scandal: Security designed to stop thieves hot-wiring almost every modern motor has been cracked

    Car hacking scandal

    Security designed to stop thieves hot-wiring almost every modern motor has been cracked
    10 best placemats

    Take your seat: 10 best placemats

    Protect your table and dine in style with a bold new accessory
    Ashes 2015: Alastair Cook not the only one to be caught in The Oval mindwarp

    Cook not the only one to be caught in The Oval mindwarp

    Aussie skipper Michael Clarke was lured into believing that what we witnessed at Edgbaston and Trent Bridge would continue in London, says Kevin Garside
    Can Rafael Benitez get the best out of Gareth Bale at Real Madrid?

    Can Benitez get the best out of Bale?

    Back at the club he watched as a boy, the pressure is on Benitez to find a winning blend from Real's multiple talents. As La Liga begins, Pete Jenson asks if it will be enough to stop Barcelona
    Athletics World Championships 2015: Beijing witnesses new stage in the Jessica Ennis-Hill and Katarina Johnson-Thompson heptathlon rivalry

    Beijing witnesses new stage in the Jess and Kat rivalry

    The last time the two British heptathletes competed, Ennis-Hill was on the way to Olympic gold and Johnson-Thompson was just a promising teenager. But a lot has happened in the following three years
    Jeremy Corbyn: Joining a shrewd operator desperate for power as he visits the North East

    Jeremy Corbyn interview: A shrewd operator desperate for power

    His radical anti-austerity agenda has caught the imagination of the left and politically disaffected and set a staid Labour leadership election alight
    Isis executes Palmyra antiquities chief: Defender of ancient city's past was killed for protecting its future

    Isis executes Palmyra antiquities chief

    Robert Fisk on the defender of the ancient city's past who was killed for protecting its future