Chapter 15 Neurochemistry

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Chapter 15 Neurochemistry Behavior

• Structure ? Behavior
• how can we relate structure to behavior?
• Hypothalamus and Pituitary
• ANS
• Diffuse Modulatory Systems (vs. precise motor and
  sensory pathways)

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I. Hypothalamus

• A. Location (15.2)
• B. Function
• 1. integrates somatic and visceral motor
  responses in accordance with the needs of the
  brain
• 2. homeostasis the maintenance of a constant
  internal environment
• C. Periventricular zone (15.3)

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I. Hypothalamus

• D. Neurohormones
• 1. magnocellular neurosecretory neurons (15.4)
• 2. axons to posterior lobe of pituitary
• 3. oxytocin
• a. contraction of pregnant uterus milk
  ejection

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I. Hypothalamus

• D. Neurohormones
• 4. vasopressin (ADH) (15.5)
• a. increased water retention in kidney
• 1) regulates blood volume salt
  concentration BP
• b. baroreceptors in CV system
• c. salt receptors in hypthalamus

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I. Hypothalamus

• E. Hypophysiotrophic hormones (15.6)
• 1. periventricular parvocellular
  neurosecretory neurons
• 2. hypothalamo-pituitary portal circulation
• 3. releasing hormone
• 4. inhibiting hormone
• 5. affects anterior pituitary secretions

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I. Hypothalamus

• F. HPA Stress circuit (15.7)
• 1. Stress stimulus - corticotropin releasing
  hormone (CRH) from periventricular hypothalamus
• 2. CRH stimulates ACTH from anterior lobe of
  pituitary

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I. Hypothalamus

• F. Stress circuit (15.7)
• 3. ACTH stimulates adrenal cortex to secrete
  cortisol
• 4. Cortisol promote metabolism, resist stress
  (incr. Glucose), antiinflammatory, depress immune
  response

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I. Hypothalamus

• F. Stress circuit (15.7)
• 5. Feedback cortisol reduces CRH release, also
  affects other CNS areas
• 6. Output to ANS preganglionics, both
  sympathetic and parasympathetic

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I. Hypothalamus

• G. Stress and sexual orientation (?)
• video-Dorner hypothesis increased stress in
  utero results in increased homosexuality (decr.
  testestorone). 3 min
• ?stress??CRH???LH,FSH??testes? brain

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II. Autonomic Nervous System

• A. Motor pathways
• 1. sympathetic (15.9)
• a. preganglionic nerve cell bodies in T-L
  spinal cord levels
• 1) intermediolateral cell column
• b. postganglionic nerve cell bodies in
  sympathetic chain ganglia

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II. Autonomic Nervous System

• A. Motor pathways
• 2. parasympathetic (15.9)
• a. preganglionic nerve cell bodies in
  brainstem and sacral spinal cord
• b. postganglionic nerve cell bodies in
  ganglia near targets

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II. Autonomic Nervous System

• B. Comparison of 2 divisions (15.8)

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II. Autonomic Nervous System

• C. Functions behavioral changes
• 1. sympathetic div. fight or flight response
• 2. parasympathetic div. energy conserving

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II. Autonomic Nervous System

• D. Enteric division (15.10)
• 1. gastrointestinal innervation
• a. myenteric plexus
• b. submucosal plexus
• 2. afferent efferent ANS
• 3. function digestion
• a. peristaltic contractions
• b. secretions
• c. blood supply

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II. Autonomic Nervous System

• E. NT
• 1. preganglionic sympathetic ACh
• a. nicotinic AChR
• 2. preganglionic parasympathetic ACh
• a. nicotinic AChR
• 3. postganglionic sympathetic NE
• 4. postganglionic parasympathetic ACh
• a. muscarinic AChR

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Review-Nicotinic AChR

• A. Nicotinic AChR Structure (6.17)
• 1. 5 polypeptide subunits
• 2. 4 transmembrane domains/subunit
• 3. 2 ACh receptor sites
• 4. e.g., NMJ

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Review-NE Receptors

• Metabotropic Receptors
• C. G-protein effector proteins
• 2. adenylyl cyclase (6.26)
• a. cAMP
• b. NE b R (), NE a2 R (-)
• c. PKA

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Review-Muscarinic AChR

• Metabotropic Receptors
• C. G-protein effector proteins (6.24)
• 1. muscarinic AChR
• 2. Activated G- protein
• 3. G subunit activates
• K channel
• (slows heart)

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III. Diffuse Modulatory Systems

• A. Locus Coeruleus NE
• 1. structure (15.11)
• a. cell body in pons
• b. diffuse axons
• 1) cerebral cortex
• 2) thalamus
• 3) hypothalamus
• 4) olfactory bulb
• 5) cerebellum
• 6) midbrain
• 7) spinal cord

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Locus Coeruleus Anatomy

• Cross section of rostral pons

http//www.meddean.luc.edu/lumen/MedEd/Images/Neur
oLab/nl22sl.jpg
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III. Diffuse Modulatory Systems

• A. Locus Coeruleus NE
• 2. function (15.11)
• a. attention
• b. arousal levels
• c. recall that NE sympathetic div.

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III. Diffuse Modulatory Systems

• B. Raphe System 5HT
• 1. structure (15.12)
• a. brainstem raphe nuclei
• b. diffuse axons
• 1) similar to locus coeruleus
• 2. function
• a. sleep-wake cycles
• b. sleep stages
• c. mood affect
• d. descend. pain influ.

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Raphe Anatomy

• Cross section of rostral pons

http//www.meddean.luc.edu/lumen/MedEd/Images/Neur
oLab/nl21sl.jpg
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III. Diffuse Modulatory Systems

• C. Substantia nigra ventral tegmental area DA
• 1. SN projection to striatum (15.13)
• 2. VTA to frontal lobe
• a. mesocorticolimbic DA system
• b. pleasure path (?)

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Pleasure Center?

• Video nucleus accumbens, DA circuit
• 8 minutes-Heath, Olds, Fibiger
• Read pp. 600-604, Reinforcement and reward

http//www.vh.org/Providers/Textbooks/BrainAnatomy
/Ch5Text/Section30.html
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III. Diffuse Modulatory Systems

• D. Basal forebrain brainstem system ACh
• 1. medial septal nuclei (15.14)
• 2. basal nucleus of Meynert (ACh)
• 3. projections to neocortex limbic system
• 4. Alzheimers d.

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Basal Forebrain Anatomy

• Coronal section at level of anterior commissure.
• Basal nucleus of Meynert is area ventral to
  anterior commissure and basal ganglia

http//www.vh.org/adult/provider/anatomy/BrainAnat
omy/Ch5Text/Section31.html
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III. Diffuse Modulatory Systems

• E. Pharmacology
• 1. LSD (lysergic acid diethylamide)
• a. 5HT agonist
• b. activates 5HTR on presynaptic axons
• c. inhibits 5HT firing
• d. hallucinogen
• e. unknown cause-effect

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III. Diffuse Modulatory Systems

• E. Pharmacology
• 2. cocaine amphetamine (15.15)
• a. sympathomimetic
• b. block reuptake
• c. increase alertness self-confidence,
  decrease appetite
• d. addictive (pleasure path?)

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III. Diffuse Modulatory Systems

• F. Depression
• 1. affective disorder
• a. cannot experience happiness
• b. insomnia
• c. loss of appetite
• d. feeling of worthlessness guilt
• 2. Types of depression
• a. typical
• b. atypical
• c. SAD

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III. Diffuse Modulatory Systems

• F. Depression
• 3. SAD video of patient interview and treatment

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III. Diffuse Modulatory Systems

• F. Depression
• 3. SAD
• a. suprachiasmatic nucleus
• 1) hypothalamic nucleus
• 2) biological clock
• 3) retinal input

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III. Diffuse Modulatory Systems

• F. Depression
• 4. treatments (15.16)
• a. tricyclic compounds (imipramine)
• 1) block reuptake of NE 5HT
• b. fluoxetine (Prozac)
• 1) 5HT reuptake inhibitor
• c. MAO inhibitors (phenelzine)
• 1) inhibit breakdown of 5HT NE
• d. ECT

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III. Diffuse Modulatory Systems

• G. Schizophrenia
• 1. type I
• a. delusions
• b. hallucinations
• c. disordered thoughts
• 2. type II
• a. flat affect
• b. catatonia
• c. lack of speech

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III. Diffuse Modulatory Systems

• G. Schizophrenia
• 3. related to increased DA
• a. neuroleptics block DAR (15.17)

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III. Diffuse Modulatory Systems

• G. Schizophrenia
• 3. Video interviews with several
  schizophrenics and doctors (16 min.)