University of East Anglia
Scientists at the University of East Anglia in collaboration
with the University Pompeu Fabra in Barcelona have found a way to separate the
medical benefits of cannabis from its unwanted side effects.
The research comes from the team that discovered how the main
psychoactive ingredient in cannabis, known as THC, reduces tumour growth in
cancer patients.
Their latest findings, published today in the journal PLOS
Biology, reveal how the cognitive effects of THC are triggered by a pathway
which is separate from some of its other effects.
The research was carried out in mice, but it is hoped that the
breakthrough will pave the way for safe cannabis-based therapies that do not
cause alterations in mood, perception or memory.
Dr Peter McCormick, from UEA's school of Pharmacy, said:
"THC, the major active component of marijuana, has broad medical use --
including for pain relief, nausea and anxiety. Our previous research has also
found that it could reduce tumour size in cancer patients.
However it is also
known to induce numerous undesirable side effects such as memory impairment,
anxiety and dependence.
"There has been a great deal of medical interest in
understanding the molecular mechanisms at work in THC, so that the beneficial
effects can be harnessed without the side-effects.
"THC acts through a family of cell receptors called
cannabinoid receptors. Our previous research revealed which of these receptors
are responsible for the anti-tumour effects of THC. This new research demonstrates
how some of the drug's beneficial effects can be separated from its unwanted
side effects."
The research team carried out behavioural studies in mice and
investigated how pathways in their brains operate under THC. They found that
the absence of a particular serotonin receptor (5HT2AR) reduced some of the
effects of THC -- such as its amnesic effect, based on a standard memory test.
But treatment to reduce 5HT2AR did not change other effects of THC, including
pain relief.
"This research is important because it identifies a way to
reduce some of what, in medical treatment, are usually thought of as THC's
unwanted side effects, while maintaining several important benefits including
pain reduction."
But Dr McCormick added that patients should not be tempted to
self-medicate.
"Patients should not use cannabis to self-medicate, but I
hope that our research will lead to a safe synthetic equivalent being available
in the future."
