1b. List and describe briefly the major structures of the brain, as presented in your textbook, including the function of those elements that are most related to psychoactive drug reaction. The first layer of the brain is the cortex which covers the top and sides of the brain. This area controls reasoning and language, and this area will be less active when under sedative drugs. The basal ganglia are located underneath the cortex and it is made up of by the striatum. The striatum controls muscle tone and is part of the dopamine pathway which is a potential transport highway for psychoactive drugs.
The hypothalamus is at the base of the brain and serves as liaison between the brain and pituitary gland. The pituitary hormonal output is involved in behaviors such as feeding and temperature regulation. The limbic system affects emotion, location memory, and physical activity. Along the brain stem are the medulla, midbrain, and pons from which contain the bulk of neurons that create dopamine, norepinephrine, and serotonin. The lower brain stem controls vomiting and respiratory functions. If affected, the respiratory function can be suppressed by drugs.
1c. Describe the life cycle of a typical neurotransmitter.
A cell membrane with the uptake of a particular precursor absorbs amino acids to create a neurotransmitter. The amino acids undergo synthesis with a reaction with enzymes to become a neurotransmitter. Once created, the neurotransmitters are stored in vesicles until they are released into the synapse. Once released, the neurotransmitters will attempt to attach to the membrane of neurons. If the neurotransmitter does not make it to the neuron, then it will either absorb in the originating cell or be metabolized within the synapse.
2b. Differentiate between drug disposition tolerance, behavioral tolerance, and pharmacodynamics tolerance, and provide reasons why these concepts should be taken into account when determining the effects of a drug. Drug disposition tolerance is defined as the increase of the drug’s rate of metabolism or removal. The user may increase the amount of a drug taken due to the drug being metabolized too quickly or being removed from the body. A person may compensate their behavior when exposed to a drug overtime such as learning to drive while intoxicated. The impairment is reduced and this is known as behavioral tolerance. Pharmacodynamics tolerance is the main contributor to the need to increase the dosage of a drug in order to avoid withdrawal symptoms. The user does not feel the same effects of a dosage so the dosage must be increased in order to get the same feeling.
2d. Provide several specific personal and societal steps you would recommend in an effort to reduce the likelihood of adverse reactions to drugs taken in combination. The largest deficit that can be produced to avoid adverse reactions to drug taken in combination is to avoid doing it all such as alcohol and other depressants. Individuals that need to take multiple medications such as person with diabetes and high blood pressure need to be carefully monitored and educated on the effects of the medications individually and the effects of the medications when combined.
3b. Explain the basic rationale and theoretical foundations for the extensive use of amphetamine in the treatment of ADHD (attention-deficit hyperactivity disorder). ADHD individuals have deficits involved with the functions of executive control within the brain. This control center affects concentration, hyperactivity, and learning. Amphetamines have been shown to produce a calming effect upon the individual from the amphetamines ability to increase brain catecholamine activity whereas ADHD individuals suffer from catecholamine deficits in the prefrontal cortex.
3c. Provide your personal viewpoint on major concerns about ADHD diagnoses and the efficacy of drug treatments that have led to recent controversy. The basis of diagnoses of ADHD has not been fully researched due to any widely accepted knowledge as to why stimulants are effective in treating hyperactivity. The causes of ADHD are still not thoroughly understood. There have also been non-stimulant drugs that have been shown to be just as effective as stimulants such as Strattera and Atomoxetine. I believe that ADHD itself is a complicated issue that requires multiple points of attack such as the use of stimulant and non-stimulant drugs. What may work on one individual may not work on another.
4a. Provide evidence of your understanding of the ways in which time course events of barbiturate and benzodiazepine actions contribute to the onset of psychological and/or physical dependence. Barbiturate are fast acting drugs that may work within fifteen minutes and stay in the system for up to three hours. Due to the rapid activity of the barbiturates, they serve as a strong reinforcement to users due to the drug produced a desired effect quickly and leaving the body just as quickly. Benzodiazepine takes longer to initialize, but also stay in the body for up to ten hours. Barbiturates are taken in higher doses more rapidly, while Benzodiazepine is taken at lower does. Withdrawal symptoms of barbiturates from chronic symptoms are severe due to the rapidness the drug leaves the user’s body without the user’s body being able to adapt to the drug adequately.
4b. Describe the key functions of GABA (g-aminobutryic acid) in producing the effects of various sedative-hypnotic agents, with specific reference to benzodiazepines. GABA is a neurotransmitter that is found in CNS areas and deals with inhibitory functions. Benzodiazepine molecules are strongly attracted to the GABA receptor sites and when bound to the GABA receptor, the Benzodiazepine molecules will increase the inhibitory effects of GABA on the receptors.