Pharmacology is the study of the composition, uses, and the effects of drugs. There are four subdivisions to pharmacology that tell us about drugs and the body and they are: pharmacokinetics, pharmacodynamics, pharmacotherapeutics and toxicology. Pharmacokinetics is what the body does to drugs such as absorption, distribution, metabolism, etc. The study of what effect drugs have on the body is pharmacodynamics which includes the effect of drugs and the mechanisms of drug action. The use of drugs in treating diseases is pharmacotherapeutics and an example of this is chemotherapy. Toxicology is the study of poisons (Pellicio, Pharmacology Lecture, 2018).
The nervous system is made up of the central nervous system and the peripheral nervous system. The central nervous system is compose of the brain and spinal cord. The peripheral nervous system is composed of all the nerves that exit the spinal cord. The peripheral nervous system is further broken down to autonomic nervous system that controls the sympathetic and parasympathetic nervous system, and the somatic nervous system that controls voluntary actions. The sympathetic nervous system activates the “fight or flight or freeze” responses of the body while the parasympathetic nervous system brings us down, relaxes and conserves energy (Pellicio, Neuroscience and Psychoactive Drugs PowerPoint, 2018).
The brain communicates through a process called neurotransmission. This is when nerve cells called neurons transmit both chemical and electrical signals. These are known as the messengers of the brain. Neurons send impulses to one another and to other cells outside the nervous system. These neurons never touch each other and this impulse is called an action potential. The impulse originates in the dendrite (the finger like projection surrounding the cell body and nucleus) which then gets integrated into the cell body and then transmitted down the axon to the synaptic knob. After that it goes to the synaptic vesicles and then to the synaptic gap where the neurotransmitters release the chemical signal. The next neuron then picks up the chemical signal and through the repetition of sequential events the nerve impulse is conducted (Pellicio, Neuroscience and Psychoactive Drugs PowerPoint, 2018).
The reward center in the brain is responsible for driving our feelings as well as our motivations (Pellicio, Neuroscience and Psychoactive Drugs Lecture, 2018). This area of the brain was discovered in 1954 by James Olds and Peter Milner, during Olds’ experiments on rodents. During these experiments Olds implanted rats with electrodes into their nucleus accumbens, which is one of the brain’s regions that is involved in the brain reward circuit. The rodents would tap on the button which would then lead to stimulation of an electrode and neuronal structure. The outcome would be that hungry animals would demonstrate a preference for self-stimulation over food and drink to the point of starvation. This stimulation became even more rewarding than survival behaviors (Pellicio, Neurobiology of Addiction PowerPoint, 2018).
The primary neurotransmitter of the reward pathway is dopamine, and drugs of abuse share the same common action that they increase dopamine levels (Pellicio, Neurobiology of Addiction PowerPoint, 2018). Dopamine naturally increases in response to rewards such as food, sex, water and nurturing; which is why it is known as “the feel good chemical” (Pellicio, The Reward Circuit PowerPoint, 2018). When cocaine is taken, dopamine increases are exaggerated and communication is altered (Pellicio, Neurobiology of Addiction PowerPoint, 2018). This causes addiction over time reinforcing the behavior as rewarding or pleasurable causing loss of control for the individual requiring a higher dose to achieve the same effect (Pellicio, Introduction to the Brain PowerPoint, 2018).
Although most drug abusers start out as recreational users, over time the individual experiences an urgent need or powerful desire for drugs. Unfortunately the very same reward system that ensures our survival also rewards the negative behavior of drug use. This causes the individual to continuously repeat these harmful behaviors. Addictive substances and behaviors also trigger the release of dopamine which in turn rewards an individual with a pleasant sensation. In turn pushing an individual to repeat these harmful behaviors over and over again despite the negative outcomes and potential deadly side-effects.. The circuit most associated with reward is in the mesolimbic pathway found in the brain stem. Within this pathway there is an area called the ventral tegmental area (VTA). The VTA communicates with the nucleus accumbens which is also known as the reward center within the brain. When a drug is taken it releases varying amounts of dopamine into the nucleus accumbens. Although different drugs have different effects in the nucleus accumbens they all activate the same reward system (A. Tom Horvath, 1995-2018).
In conclusion the brain is a very delicate yet highly adaptive organ. Our brains play a vital role in every bodily function we possess. By taking drugs or medications we alter the very delicate balance within our bodies be it for the good or the bad. In the case of taking illegal substances the delicate functions of our brain can be disrupted and a negative response can occur even though the individual finds it rewarding. On the other hand some prescribed medications can be used to alter our brain chemistry for a better outcome. An example of this is someone who is depressed is given an SSRI and a positive result occurs. The brain is an amazing organ that is still being studied today and all these studies that are out there show us how we’ve only discovered partially what the brain is capable of.
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