12 11 Drugs and Hormones

12 11 Drugs and Hormones - Drugs of Abuse What is a drug?...

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Unformatted text preview: Drugs of Abuse What is a drug? Any biological substance that alters or affects some bodily functions Psychoactive drugs: chemical substances that change moods, behav, & perceptions Psychopharmacology: studies how drugs alter the NS and behavior Common Properties Toler ance- dec. responsiveness to a drug User has to take amts of drug to feel the same effects Small Large Drug dose Little effect Big effect Drug effect Response to first exposure After repeated exposure, more drug is needed to produce same effect Common Properties Withdr awal- unpleasant physical rxn to lack of drug Causes a variety of symptoms: Sweating Shaking Nausea/ vomiting Sleeplessness Loss of appetite Common Properties Physical dependence- body/brain chemistry are adapted to drug Cannot function w/out its presence Psychological dependence- people believe they need the drug to respond to stresses of daily living Neural basis of drug activity Mesolimbic DA Pathway Located in ventral tegmental area (VTA) and projects to basal ganglia, and to limbic system via the NAc, and to medial prefrontal cortex. I nvolved in modulating behavioral responses to stimuli that activate feelings of reward (motivation) and reinforcement through DA. Mesolimbic Dopamine Pathway Pathway triggered during drug intake and drug-seeking behavior (Phillips et al., 2003) Same pathway is used during natural rewards (i.e. food, sex) Blood-brain barrier Prevents substances (including drugs) from entering CNS via bloodstream Small molecules (i.e. oxygen, carbon dioxide) are fat soluble and can freely cross the BBB. Large, charged molecules ( glucose, fats, amino acids) must be actively transported across the BBB Endothelial cells and astrocytes keep drugs out of brain Some areas of the brain are barrier free Barrier-free brain sites Routes of drug administration Oral: safest, easiest, and most common route I nhalation I njection Transdermal The more barriers the drugs have to go through, the more drug needed to have a desired effect I nhalation Advantage: Fastest method, 7-10 seconds for the drug to reach the brain Disadvantages- Most addictive route b/c of speed of entry Difficulties in regulating the exact amount of dosage I njection I ntravenous- into a vein I ntramuscular- into a muscle Advantages- 15-30 sec for I V, 3-5 minutes for I M and subcutaneous...
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This note was uploaded on 11/19/2010 for the course PSYCH 2275 taught by Professor Weiner,j. during the Spring '10 term at CUNY Hunter.

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12 11 Drugs and Hormones - Drugs of Abuse What is a drug?...

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