This report will aim to explain the chemistry of the drug Phencyclidine, commonly known as PCP, and the ways in which it affects the brain, its processes and more precisely, body control and movement.

The topic of consideration is the most vital function of a human. Body control is not only simply moving muscles in a person’s arms and legs, it is every intricate movement within the body, from moving small muscles in the mouth to form speech to walking. By having the ability to control these normal functions, a person can live a normal functioning life, however, if these functions are restricted in any slight way, a person becomes separated from society as any normal task can become difficult and unbearable.

This report will discuss the history of PCP and the chemistry behind the drug, including how it is synthesised and its chemical properties. It will explain how it enters the body and then blood stream and what it does to affect the brain’s connections as well as discuss other symptoms. The report will then discuss how exactly PCP alters the brain’s ability to control the body.

Background

Phencyclidine, or PCP, is a dissociative drug, which are a class of hallucinogens. Dissociative drugs are known for changing perceptions of sound, sight and connections with one's’ surroundings. PCP was originally developed and marketed as an anaesthetic pharmaceutical in the 1950’s, by Parke, Davis and Company. PCP is used on the streets under the names of angel dust, wack, ozone, embalming fluid, rocket fuel and many others. It was initially used as a surgical anaesthetic and was later used by veterinarians as an animal tranquilizer. By 1965, the drug’s use for the medical community had ended, due to the adverse side effects of the drug, however, it remained popular as an animal tranquiliser. 

There are various ways to synthesize PCP, the most common using a Nitrile intermediate. This method occurs by preparing a nitrile intermediate (or PCC), and reacting this intermediate with a Grignard reagent (Phenyl magnesium bromide). To prepare the PCC, Cyclohexanone is reacted with Hydrochloride salt of piperidine and the aqueous Sodium cyanide (NaCN), or Potassium cyanide (KCN). This is set as a crystalline precipitate which is then washed with cold water, and dried. The Grignard reagent, is formed by the interaction of Bromobenzene and Magnesium metal before then reacting with the PCC to produce the final compound. This process is demonstrated in Figure 1.

Figure 1: Synthesis of Phencyclidine using a nitrile intermediate. Retrieved from http://www.lycaeum.org/rhodium/chemistry/pcp/cn_synth.html

Figure 2: Chemical structure of Phencyclidine. Retrieved from https://livertox.nih.gov/Phencyclidine.htm

In its original and purest form, PCP is a solid that appears as a white crystalline powder. A PCP molecule contains 43 atoms in total, being 25 hydrogen, 17 carbon and 1 nitrogen, and has the molecular formula of C17H25N. Figure 2 above shows the structure of the molecules and the bonds. On each hexagon, the corners indicate a Carbon molecule, and the hexagon that had double lines indicates double bonds between Carbons. The hydrogen molecules are not indicated on the structure, but the small ‘N’ represents the nitrogen atom.  PCP has a boiling point of 136 degrees Celsius, a melting point of 46.5 degree Celsius and a water solubility of 0.00325 mg/mL, and is also able to dissolve in Ethanol. When dissolved in water, a clear liquid is produced. The drug has a molecular weight of 243.4 g/mol and high reactivity with other substances from alcohol to Heroin. 

Phencyclidine can be taken in multiple ways via an injection, snorted, orally taken as a pill, or smoked. The most common method of taking PCP is smoking it, either in a pipe or a cigarette form. This is done by spraying or sprinkling the liquid form of PCP onto a kind of leafy material, often herbs such as oregano, mint, parsley as well as the drug, marijuana, or by dipping cigarettes into a solution of PCP. When smoked, the PCP enters the lungs and from there travels along the artery through the heart, and into the bloodstream. PCP is then spread throughout the body and through to the brain. 

When taking moderate amounts of PCP, the symptoms can make a person feel detached from their normal lifestyle, as well as numbness in the body, slurred speech and loss of coordination. When taken at high dosages, PCP affects the cardiovascular system via lowered blood pressure, pulse rate and poor respiration. Other symptoms such as nausea, vomiting, drooling, loss of balance and blurred vision may also occur. 

As the brain reacts to PCP, it prevents the actions normally caused when a neurotransmitter attaches to its receptor in the brain. This neurotransmitter is a powerful excitatory neurotransmitter known as Glutamate. Glutamate is responsible for sending signals between nerve cells in the brain. PCP stops Glutamates activity by blocking N-Nitrosodimethylamine (or NMDA) receptors, this causes more neurons to fire, which can lead to over-excitation of the receiving nerve cell. This may cause damage or death of the cell altogether. PCP, like all drugs of addiction, affects the brain’s reward centre. It does this by interfering with the communication process, causing the neurons in the brain to flood the brain with dopamine. Dopamine, a neurotransmitter responsible for communication within the brain, under regular circumstances is released from the brain when it responds to something it finds pleasurable. In cases, PCP can cause certain chemical imbalances with the brain. These chemical imbalances may lead to lower levels of pleasure or increased negative mood states.

As well as NMDA, PCP may inhibit the action of the neurotransmitter Nicotinic acetylcholine receptor (or nAChR). The nAChR moderates to an extent the effects of Acetylcholine, a neurotransmitter which serves as a transmitter to all neuromuscular connections between the skeleton and muscles. The inhibition of NMDA and nAChR can impact synaptic development and plasticity in the brain, which is the brain’s function of changing and making neural connections in relation to the environment and what is learnt. With prolonged use of PCP, neural connections will be unable to fully develop, which may lead to memory loss.

Discussion

In the brain the Primary Motor Cortex, located in the back of the frontal lobe, is a principal area involved in motor function, or movement. The primary motor cortex is mainly used to generate neural impulses that control the execution of movement as it occurs. For movement to occur, there must be a connection between the brain and the muscles, this connection is made via neurons. Due to its effect on the neurotransmitter Glutamate, PCP can disrupt the communication between neurons in the brain. As PCP inhibits Glutamate activity in areas of the brain such as the cerebellum changes in blood pressure, breathing and pulse rate, and loss of muscular coordination may occur. The Cerebellum in the brain is also involved in body control as it is largely in control of coordination of muscles, the body, and balance. As communication lessons the user may experience muscle spasms and contractions that may deform their body movement altogether. Due to the body losing some of this function, a person may harm themselves with no knowledge of doing so. PCP, as a dissociative, hallucinogen drug, also prevents the user from experiencing pain. This has led people to physically harm themselves, including cases of people removing their own limbs and burning their bodies due to the high off the drug.

Other common symptoms of PCP include incomprehensible speech, or lack of ability to speak at all, and involuntary rapid movements of the eye, or being unable to control movements of the eye at all. These occur due to the drug affecting the area’s in the brain related to speech production, being Broca’s area located in the frontal lobe, and those that control the muscles of the eye and vision, mainly found in the brainstem, or occipital lobe. Like the Cerebellum, these areas of the brain cause these malfunctions due to lack of strong communication of the neurons.

Besides the effects that occur from inhibiting NMDA, PCP also largely shows effects as it inhibits the action of the neurotransmitter nAChR. With the connection between the skeleton and muscles no longer in full control, movement response is slow and rigid. In the case where the person needs to react and move out of the way such as from a moving car, they may be unable to do so fast enough due to the loss of action of nAChR.

Conclusion

From the information covered, it can be concluded that the drug Phencyclidine is clearly a dangerous drug to be inserting in a person’s body. By inhibiting the action of the neurotransmitters NMDA and nAChR, PCP holds many negative effects on body control. By inhibiting the action of the neurotransmitters, PCP slows down or even blocks communication throughout the brain, and from there, the rest of the body, making control of the body and everyday functions difficult. PCP is highly addictive due to its connection with the reward pathway as it causes the release of Dopamine within the brain. As the user of the drug becomes addicted and they consume more PCP, their ability to control their own body lessons. Uptake of PCP can lower the user’s blood pressure and restrict breathing, it also prevents the user from feeling pain, which may lead the person to harm themselves with no realisation. This drug has led many users to maim themselves or others and commit acts completely unrecognisable from their general personality. 
PCP takes its toll on body control as it inhibits communication throughout the brain; with this communication blocked, movement of muscles and other tasks such as speech are obstructed and the user of the drug is at risk of potentially harming themselves to an extreme.

Public Education Piece

For my public education piece I made a FakeBook profile to advise the general public of the information showed in this report.

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