Effects Of Marijuana On The Central Nervous System
Drugs do not contain highs; drugs trigger these highs. The potential for feeling high exists naturally within the human nervous system, and we have countless options for getting high without taking drugs. Small children love to spin wildly in circles. Many people go sky diving, fall in love, paint, meditate—the list is endless.
Marijuana triggers a high via the central nervous system (CNS). The CNS controls the functions of the brain and the spinal cord. There are billions of nerve cells called neurons within the CNS that are linked by an intricate web of synapses (the gaps between neurons). Perhaps you seek to move a finger to relieve the itch of a bug bite. To do this, the neurons responsible for moving your finger need to communicate with each other. The message "move my finger" is transmitted simultaneously along the neuronal system of synapses by means of neurotransmitters, which are chemicals released by the neurons to help neurons communicate with each other. Neurons are also known as messenger cells, and neurotransmitters as chemical messengers.
Neurotransmitters can be envisioned as keys that unlock specific sites on neurons called receptors. A neurotransmitter opens the receptor's lock, and it is through this key-and-lock system that messages are conveyed throughout the CNS. Most receptors are specifically tuned to accept only one type of neurotransmitter key. Hormones can also act as keys that unlock certain receptor sites. Some neurons have thousands of receptors that are specific to particular neurotransmitters.
The Marijuana High
Whether marijuana is inhaled or ingested, when THC enters the bloodstream it is delivered to the brain and the central nervous system. When the amount of THC in the brain exceeds a certain dose, a "high" is experienced, usually within 15 to 30 minutes.
In addition to reaching the brain, THC is delivered to all other parts of the body. This distribution eventually reduces the amount of THC in the blood; in turn, this reduces the amount of THC in the brain. Within two to four hours, THC levels in the brain typically fall below what is necessary for psychoac-tivity, and the user "comes down" from the high. Eventually, THC is eliminated from the body in sweat, feces, and urine.
THC In The Brain And Body
A cannabinoid is a type of chemical compound concentrated in the resin of the cannabis plant. THC is the only cannabinoid that is highly psychoactive and present in large amounts in cannabis. Until recently, there has been little information on precisely how THC acts on the brain, which cells are affected by THC, or even what general areas of the brain are most affected by it. All this changed in the 1980s and 1990s with the discovery of specific cannabinoid receptors—Cannabinoid receptor 1 (CB1) and Cannabinoid receptor 2 (CB2).
CB1 is found predominantly in the brain and is associated with many of the effects from THC. CB2 is found in the spleen and other organs and is associated with the immune system; its role is still not fully understood. The discovery of these receptors, as well as their locations in the body, has allowed scientists to learn more about how marijuana affects the human brain and body.
CB1 and CB2 can be found throughout the human body; hence, there are a variety of ways that cannabinoids can physically and psychologically affect the body's systems. As an example, the presence of CB1 receptors in the eye may explain how marijuana eases glaucoma and relieves intraocular pressure. Other research indicates that THC can block receptors in the brain and body to produce dizziness, dry mouth, and altered depth perception— all common effects of marijuana use. There appears to be an endless array of research studies that can match THC's effects with an appropriate action at a particular cannabinoid receptor site. Herein lies the ability of science to advance medicinal breakthroughs: Numerous ongoing research investigations are underway to explore site-specific medications that would specifically alleviate pain, for example, without causing dizziness or euphoria. This process is termed "selective uptake."
Cannabinoid receptors, the binding sites for THC from marijuana, are prevalent in the brain and concentrated in areas like the basal ganglia, hippocampus, cerebellum, and cerebral cortex (indicated in pink on this illustration). THC interrupts the normal communication between neurotransmitters and results in changes of behavior and physical effects controlled by these areas of the brain.
Continue reading here: Endogenous Internally Produced Cannabinoids
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