PSYC 211 - Chapter 4

PSYC 211 - Chapter 4 - prolongs presence of NT in synapse L...

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Lab animals Humans prolongs presence of NT in synapse CHAPTER 4: PSYCHOPHARMACOLOGY INTRODUCTION July 1982, California: patients showed up at neurology clinics with Parkinson-like symptoms o Such symptoms included difficulty with motor movements, paralysis, inability to speak o Patients were given L-DOPA, which increases levels of dopamine But the drugs loses its effectiveness o However, the patients were too young to have Parkinson’s disease o The source of the problem was a contaminant in synthetic opiate called MPTP o MPTP is highly toxic to the same neurons affected by Parkinson’s o Patients now treated with a drug that slows degeneration of dopamine-secreting neurons Psychopharmacology : study of the effects of drugs on the nervous system and on behavior A drug is defined as “an exogenous chemical not necessary for normal cellular functioning that significantly alters the functions of certain cells of the body when taken in relatively low doses o Exogenous: produced outside of the body o The definition specifies low doses because any substance in high enough dose can be toxic Drug effect : the changes a drug produces in an animal’s physiological processes and behavior o Eg. Opiates reduce sensitivity to pain and can induce euphoria Sites of action : the locations at which molecules of drugs interact with molecules located on or in cells of the body, thus affecting some biochemical process of these cells o Eg. Specialized receptors on cell membranes Psychopharmacology has led to the development of psychotherapeutic drugs and allows researchers to study the functions of neurons and neural circuits PRINCIPLES OF PSYCHOPHARMACOLOGY Pharmacokinetics Drug molecules in body bloodstream organs they act on Psychopharmacology : the process by which drugs are absorbed, distributed within the body, metabolized and excreted Routes of administration: o Intravenous (IV) injection of a drug dissolved in a liquid directly into the bloodstream Rapid; reaches brain in a few seconds Requires skill to perform Entire dose reaches bloodstream at once o Intraperitoneal (IP) injection into the peritoneal cavity, the space that surrounds the stomach, intestines, liver and other abdominal organs Less rapid then IV injection Intramuscular (IM) injection into a muscle Absorption through capillaries that supply the muscle For slow absorption, can mix drug with ephedrine, which constricts vessel and retards blood flow o Subcutaneous (SC) injection into the space beneath the skin Only useful for small amounts of drug Slow absorption, which can be prolonged by implanting drug as a dry pellet o Oral administration : most common for humans, not practical for animals Not used for chemicals that can be digested by enzymes that cannot reach bloodstream 1
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Eg. Insulin (use IV) o Sublingual administration by placing drug beneath the tongue Capillaries that line the mucous membrane bring drug to the bloodstream
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PSYC 211 - Chapter 4 - prolongs presence of NT in synapse L...

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