An experiment on mice conducted by US scientists has shown that a compound extracted from a plant from the buttercup family has the ability to reduce craving for marihuana, and block its effect on the brain.
Steven Goldberg of the Maryland based National Institute on Drug Abuse found that upon administration of the plant extract, the rodents lose their hankering for a synthetic version of tetrahydrocannabinol (THC), an active compound in marijuana. The treatment also blocked a reward response in the animals' brains when they did receive synthetic THC.
During the course of study, the rats were placed in a cage with a lever that they could push. As and when they leaned on the lever, they received a dose of the synthetic THC through a small tube running into their body.
It was observed that over a period of three weeks, the rats learnt how to enjoy the effects of synthetic THC, and frequently administered themselves the drug. But the animals who received saline solution did not press the lever often.
Goldberg then injected the rats with methyllycaconitine (MLA), a compound derived from the seeds of the Delphinium brownii plant, and noted that it had a dramatic effect on the rats' behaviour, viz, reduction in the pushing of lever for synthetic drug THC by 70 per cent.
According to the researchers, he drug did not seem to otherwise change the rats' movement and co-ordination, and had no other apparent side effects.
Researchers also checked the effects of the plant extract on the rats' brains through a technique called microdialysis. They had a close look at the tiny fluid samples from a reward-signalling area of the brain known as the nucleus accumbens, which sits near the base of the head.
When rats receive synthetic THC, levels of the reward chemical dopamine normally shoot up in the nucleus accumbens, but the plant extract blocked the release of dopamine in this brain region.
"The increases in dopamine are virtually non-existent because of MLA," the New Scientist quoted Goldberg as saying.
The scientists, however, are clueless as to the mechanism by which MLA works.
Goldberg also stressed the need for developing medications that may help cannabis addicts overcome their drug problem, and is of the opinion that more options, such as one based on MLA, must be explored.
"Each patient is different and what works in one might not work in another," said the researcher.