subcool
Well-Known Member
Reversible decrease in receptors explains tolerance and dependence
Monday July 18th, 2011
A new study from the National Institute of Mental Health (NIMH) explains the mechanism of action for tolerance and dependence with marijuana use. In order to understand this, you must first understand that the medicines in marijuana, called cannabinoids, attach to the body's cells through a receptor, similar to how a key fits to a lock. Once the cannabinoid binds to the receptor, a chemical reaction takes place, triggering a message that tells the body to react in a certain way. Humans have two types of cannabinoid receptors, called CB1 and CB2.
Previous studies in rats showed that with repeated exposure to marijuana, the number of cannabinoid receptors in the brain was reduced. If the cannabinoid has no place to bind, no reaction can take place, and therefore no effect of marijuana is felt.
No one had studied this in humans until just recently. The NIMH study, published online July 12, 2011, used PET scans to demonstrate that humans who chronically smoke marijuana had a reversible reduction in the number of CB1 receptors that were available to bind the cannabinoids. This reduction was found to be correlated with years of marijuana smoking (meaning the longer you smoked, the less receptors available) and it was also found to be correlated to one location in the brain (the cortex).
After the human subjects in the study stopped using marijuana (they were continuously monitored in a secure research unit) the CB1 receptors increased to normal levels in about 4 weeks. This proves that the reduction in receptors is reversible.
Tolerance and dependence with marijuana does not occur as often as many other drugs (see below) but it can become a problem with chronic overuse. Many medical marijuana patients find little to no problems with tolerance and dependence because they moderate their use, that is, they use it when needed for medical purposes, not as a recreational drug.
If you are a medical marijuana patient who uses this medication daily, you may want to take some time off to allow the cannabinoid receptors to open up again. This will allow your tolerance to drop and will help minimize any dependency symptoms that could arise if you stopped completely. Many patients find that they only need to take 1-2 weeks off every few months, especially if they are not using the medication multiple times during the day (as opposed to using it just once a day). If you are using marijuana multiple times a day every day and tolerance is an issue, you may consider taking 4 weeks off to allow your receptors to return to normal.
It is great to see that studies like this one are being done (finally!) as more SCIENCE leads to better UNDERSTANDING and less FEAR and IGNORANCE!
Here are the numbers for risks of dependency to certain substances from an Institute of Medicine report published in 1999:
Risk of dependency on marijuana: 9%
Risk of dependency on alcohol: 15%
Risk of dependency on cocaine: 17%
Risk of dependency on opiates (heroin, opiate pain pills): 23%
Risk of dependency on nicotine: 32%
http://www.cannacenters.com/blog/New+Study+Explains+Marijuana+Tolerance?ref=420.com
Monday July 18th, 2011
A new study from the National Institute of Mental Health (NIMH) explains the mechanism of action for tolerance and dependence with marijuana use. In order to understand this, you must first understand that the medicines in marijuana, called cannabinoids, attach to the body's cells through a receptor, similar to how a key fits to a lock. Once the cannabinoid binds to the receptor, a chemical reaction takes place, triggering a message that tells the body to react in a certain way. Humans have two types of cannabinoid receptors, called CB1 and CB2.
Previous studies in rats showed that with repeated exposure to marijuana, the number of cannabinoid receptors in the brain was reduced. If the cannabinoid has no place to bind, no reaction can take place, and therefore no effect of marijuana is felt.
No one had studied this in humans until just recently. The NIMH study, published online July 12, 2011, used PET scans to demonstrate that humans who chronically smoke marijuana had a reversible reduction in the number of CB1 receptors that were available to bind the cannabinoids. This reduction was found to be correlated with years of marijuana smoking (meaning the longer you smoked, the less receptors available) and it was also found to be correlated to one location in the brain (the cortex).
After the human subjects in the study stopped using marijuana (they were continuously monitored in a secure research unit) the CB1 receptors increased to normal levels in about 4 weeks. This proves that the reduction in receptors is reversible.
Tolerance and dependence with marijuana does not occur as often as many other drugs (see below) but it can become a problem with chronic overuse. Many medical marijuana patients find little to no problems with tolerance and dependence because they moderate their use, that is, they use it when needed for medical purposes, not as a recreational drug.
If you are a medical marijuana patient who uses this medication daily, you may want to take some time off to allow the cannabinoid receptors to open up again. This will allow your tolerance to drop and will help minimize any dependency symptoms that could arise if you stopped completely. Many patients find that they only need to take 1-2 weeks off every few months, especially if they are not using the medication multiple times during the day (as opposed to using it just once a day). If you are using marijuana multiple times a day every day and tolerance is an issue, you may consider taking 4 weeks off to allow your receptors to return to normal.
It is great to see that studies like this one are being done (finally!) as more SCIENCE leads to better UNDERSTANDING and less FEAR and IGNORANCE!
Here are the numbers for risks of dependency to certain substances from an Institute of Medicine report published in 1999:
Risk of dependency on marijuana: 9%
Risk of dependency on alcohol: 15%
Risk of dependency on cocaine: 17%
Risk of dependency on opiates (heroin, opiate pain pills): 23%
Risk of dependency on nicotine: 32%
http://www.cannacenters.com/blog/New+Study+Explains+Marijuana+Tolerance?ref=420.com
