Biological Systems of Chemical Dependency (Meth)

Mechanism of Action Pharmacodynamics. Methamphetamine is a particular compound of Amphetamine. Regular amphetamines are psycho-stimulants with similar effects to that of caffeine, though not as mild. Methamphetamine is a synthesized drug that is the most potent of amphetamines (Grilly, 2001). This is because a methamphetamine molecule is a molecule with methyl group added to the structure. This methyl group allows the drug to pass quicker through the blood brain barrier (Hart & Ksir, 2011). When one discusses Methamphetamine potency, one is referring to the dose or concentration at which a substance reaches half of its maximal efficacy. Efficacy is the amount of activation once a substance is bound to the receptor it has affinity (or ability to remain bound). The maximal efficacy, therefore, is reached when increasing the dosage of a drug will no longer produce a greater activation of receptors. If one says that Methamphetamine is the most potent of Amphetamine combinations, one is stating that a dose of Methamphetamine will have a quicker activation (efficacy) rate at a lower dose than other combinations. In order for potency and efficacy to happen, a receptor must be present to be activated. While the stimulant actions of methamphetamine are generally thought to involve dopamine systems (Fleckenstein et al., 2000), it has been known for many years that methamphetamine also binds to sigma receptors Sigma receptors are present in organ systems that mediate the actions of methamphetamine (e.g. brain, heart, lung). In addition, activation of these receptors stimulates dopamine synthesis and release (Basianetto et al., 1995). The major neurotransmitters that have an increase in activity after indulging in the drug are: dopamine, norepinephrine, and serotonin. Methamphetamines wax the activity of these neurotransmitters b stimulating release rather than inhibiting reuptake (Hart & Ksir, 2011). Part of the euphoric feelings associate with methamphetamines

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