How Marijuana Affects The Brain

Weed, pot, ganja, bud, reefer, hash, Mary Jane: all names for marijuana, the drug that’s caused hippie movements and sent Taco Bell sales skyrocketing since the 60’s. Pot smokers have a negative reputation for being lazy, unmotivated, unintelligent and unpromising. They fill their lungs with skunk-smelling smoke, ballooning their heads with dopey air and fumes. But what’s happening? Is some kind of gypsy magic taking over the circle of friends, pulling uncontrollable laughter and disorientation out of a rasta-colored wizard hat?

It’s not some kind of spontaneous enchantment – it’s biology. Specific chemicals in the plant interfere with cerebral processes and alter their signals.

Many of us know the basics of neurons, cells specifically in the brain. Neurotransmitters, the chemicals between neurons, bind to protein receptors and communicate specific signals from one to another. The receptors important in this case are certain G-protein-linked receptors (Whoa! Remember those?), called cannabinoid receptors. These structures activate protein kinases and control actions such as memory, coordination, pleasure, time perception and concentration.

Typically, these receptors are naturally activated by anandamide, a neurotransmitter in the chemical group cannabinoids. Another chemical in this group, yet not found naturally in the body, is delta-9-tetrahydrocannabinol – or THC: the most prevalent chemical in marijuana. Within seconds of THC flooding the bloodstream, the chemical mimics anandamide and binds to the same neurons. Yet it doesn’t function to the same capacity as natural neurotransmitters, and immediately fires some warped signals.

When THC circulates among neurons, the first process affected is short-term memory. This is because one of the initial regions THC heads to is the hippocampus, where the majority of memory is encoded and stored. The chemical alters functions of the hippocampal neurons and inhibits recollection of material. When a smoker inhales a high dose of the pot, the structural changes of the hippocampus even prohibit new information from being registered. So if you’re (hypothetically) ever around a stoner who can’t remember where he put his car keys only five minutes ago, you can say you saw this guy named THC snatch them from his memory.

Seeping into the cerebellum and basal ganglia, the areas of the brain that control muscles movement, THC binds to even more neurotransmitters, impairing coordination. Smokers could reach for an object and miss by a long shot, or feel “floaty” as they walk from the couch to the kitchen.

All right, so why would anyone want to forget things and trip everywhere? That’s not why anyone lights up – the inviting effect of marijuana is a sense of euphoria. THC signals release of other neurotransmitters such as dopamine, a natural chemical that generates feelings of lightness, airiness and bliss. Dopamine acts as a reward system and causes an increase in pleasure sensations.

Cannabinoids also prohibit neurons from entering their rest period – basically telling them “Go, go, go, keep firing!”, causing an intense focus on only one concept. Forget thinking about the big picture or where you need to be in an hour, THC only lets you happily obsess over how ingenious your idea is or how that pillow oddly feels like a cloud.

From imagination and relaxation, to spacey memories and lethargic muscles, the cannabinoids in marijuana take a toll on neuron’s typical signal transduction pathways. And THC isn’t alone – over 400 chemicals make up the marijuana plant, 60 of which are in the cannabinoid family. These chemicals go on to affect other regions of the body, such as the lungs and heart. So no, pot isn’t a magical hippie plant – it’s an abundance of harsh chemicals that interferes with cell receptors and signal pathways, speeding up and slowing down typical cognitive processes.

About Mr. Mohn

Biology Teacher

This entry was written by Cara B. and tagged . Bookmark the permalink.

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