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Chapter 14 Manipulating the Brain. Electrical Activity in the Brain.

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Presentation on theme: "Chapter 14 Manipulating the Brain. Electrical Activity in the Brain."— Presentation transcript:

1 Chapter 14 Manipulating the Brain

2 Electrical Activity in the Brain

3 Electrical Activity at the Cellular Level + _ + _ + _ _

4 Balance There are many neurotransmitters Some excite (depolarize) Some inhibit (hyperpolarize) Some go both ways (depending on the receiving cell) A balance of excitation and inhibition

5 Drugs Alter balance Beyond the limits of excitation is seizure Beyond the limits of inhibition is respiratory failure, cardiovascular collapse and death

6 General Depressants Ethyl alcohol (the kind you drink, all others are poison) Barbiturates Anesthetics

7 General Depressants Depress electrical activity Disrupt membranes and increase action of GABA (an inhibitory neurotransmitter) All electrically excitable cells are effected –Nerves –Muscles (heart, skeletal, smooth) –Kidney

8 Inhibition is more sensitive than excitation

9 Barbiturates Sedatives and hypnotics Non-selective general depression of electrical activity Barbituric acid, pentobarbital, seconal, pentothal- How long they last

10 Barbiturate Uses Epilepsy – many types Sleeping pills Side effects –Tolerance- The more you take, the more you need to take to have the same effect –Dependence- Adverse reaction to withdrawal


12 Barbiturates – Other Side Effects Liver – increased metabolism of –Barbiturates –Steroids –Fat soluble vitamins

13 Ethyl Alcohol The kind you drink Brain Liver Cardiovascular Digestion

14 Selective depression of electrical activity in the brain Manipulation of specific neurotransmitter systems Increase inhibition Decrease excitation

15 Benzodiazepines Aka. Librium, Valium Increase the effect of GABA on the receiving cell Inhibition within a level –Reticular formation –Hypothalamus –Limbic system –Cerebral cortex

16 Benzodiazepines: Uses Sleeping pills Less depression of medullary centers than barbiturates Some types of epilepsies Parkinson’s disease Anti-anxiety


18 Benzodiazepines: Side Effects Drowsiness, fatigue, loss of co-ordination, dizziness, blurred vision, behavioral With alcohol – lethal Tolerance Dependence

19 Neurotransmitters: Excitation and Inhibition

20 Food Additives MSG (monosodium glutamate) Aspartame –40% aspartic acid –50% phenylalanine –10% methanol

21 Glycine Strychnine – glycine antagonist Exciting - even to seizures

22 Mixed Neurotransmitters Sometimes excitatory, sometimes inhibitory Depends on receiving cell Biogenic amines

23 Synthesis of Biogenic Amines Neurotransmitters Phenylketonuria (PKU)

24 Biogenic Amines Adrenalin/noradrenalin –Stress Responses –Reward –Arousal –Mood Dopamine Motor control Social behavior Hypothalamic releasing factors

25 Serotonin AKA – 5-hydroxytryptamine Lining of digestive system Platelets Brain –Mood –Drives –Thinking and perception –Sleep and attention –Hypothalamus

26 Mechanism of Transmission

27 Many Drugs Cross-reactivity between receptors Subtypes of receptors Drugs –Antagonists –Agonists –Block destruction –Block re-uptake –Cause release

28 “Speeds” Amphetamine and derivatives Cocaine Both cause release and block re-uptake Acute stress response Euphoria, paranoia Extreme focus of attention Seizures

29 “Speed” Uses Attention deficit disorder (ADD) Diet Pills Recreation

30 Speed and the Sympathetic Nervous System

31 Depression What is it? Unipolar Bipolar (manic – depression cycling)

32 Antidepressants Hypothesis: depression is caused by depletion of one or more of the biogenic amines in the limbic system

33 Tricyclic Antidepressants Blocks recovery of noradrenalin and serotonin Causes build-up of both Interferes with both sympathetic and parasympathetic control

34 Monoamine Oxidase Inhibitors Block the enzymes that break down monoamines Biogenic amines build up in nerves and leak out Monoamines are in many places the besides brain…also in foods

35 Prozac and Paxil Blocks the reuptake of serotonin which causes build up Adverse effects –Headache –Nausea –Dry mouth –Dizziness, tremors –Sexual dysfunction Hallucinations, aggression (LSD)????????????

36 Lithium Li + …….Na + Limited range between efficacy and toxicity Kidney toxicity

37 Mental Disorders Psychosis Schizophrenia Hypothesis: serotonin deficiency in limbic system Psychotomimetic drugs (LSD) Dopamine excess???? Parkinson’s disease

38 Drugs Phenothiazines –Block dopamine and other biogenic amines –Even out behavior, sedation –Muscle tremors –Lots of problems but makes person tractable

39 Epilepsy Uncontrolled electrical activity in the brain Benzodiazopines, barbiturates Phenytoin (dilantin), Valproate – Na + channel blocker Ca ++ channel blockers

40 Xanthines Blocks the breakdown of the second messenger cAMP Caffeine, theobromine - food Theophylline - drug

41 Nicotine Stimulates sympathetic response Attention Drug seeking behavior

42 Cannabinoids (AKA: marijuana)  Mixture of compounds >Cannabinoid receptors: two types Immune Nervous system >endocannabinoids – anandamide (synthesized from arachidonic acid) >synthetic (pharmacological)

43 Cannabinoids cont. >Psychoactive (general feeling of well-being, heighten awareness of sound and sight) most active psychotrophic: delta-9– tetrahydrocannabinol >Immune system: anti-inflammatory >Nervous system: AIDs and cancer: decrease nausea, increase hunger Glaucoma: decrease intraocular pressure chronic pain: decrease perception

44 Balance Drugs alter the balances of the brain

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