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2011-03-30 01:47:43
Veterinary Pharmacology

Exam II
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  1. Autonomic Nervous System
    regulates visceral functions that occur without conscious control; all visceral organs except skeletal muscle
  2. ANS orginates from _____ (_____ and ____ ____) and divided into two parts:
    CNS, brain, spinal cord

    • 1. Parasympathetic
    • 2. Sympathetic
  3. autonomic ganglia
    specialized complex structures residing outside the spinal cord that contain axodendritic synapses between preganglionic and postganglionic neurons
  4. Types of Neurotransmitters

  5. Acetylcholine is synthesized in the ____ from _________ and _____ by ______ _____________
    neurons, acetyl CoA, choline, choline acetyltransferase
  6. Acetylcholine is broken down in the ______ _________ or the ______-______ _________ by _________ ______
    ganglionic junction, neuro-effector junction, acetylcholine esterase
  7. ACh's effects are mediated through two subtypes of receptors
    1. Muscarinic (M) receptors: present in the neuro-effector junction of the parasympathetic division

    2. Nicotinic (N) receptors: present in the autonomic ganglia of both and the neuro-muscular junction
  8. NE and epinephrine are mediated by two receptor subtypes:
    alpha receptors: alpha1, alpha2

    beta receptors: beta1, beta2
  9. alpha 1 receptors
    present in the arteriolar smooth muscles. Activation leads to vasoconstriction (blood vessels), increase blood pressure
  10. alpha 2 receptors
    found pre-gangionically and in the CNS. Activation leads to decrease in the sympathetic flow from CNS

    NOT post-synaptic
  11. beta 1 receptors
    found in the heart and kidney. Activation leads to increase HR, foce of contraction, and release of renin from kidney causing hypotension, stimulate heart
  12. beta 2 receptors
    found in smooth muscles of blood vessels and bronchi. Activation leads to vasodilation and bronchodilation. Important in lungs
  13. Direct-Acting Parasympathomimetics
    stimulation of M receptors at the neuro-effector junction with little or no N receptor stimulation
  14. Indirect-Acting Parasympathomimetics
    these agents do not stimulate the M receptors but prolong the duration of action of endogenous ACh by inhibiting ACh esterase, the enzyme that breaks down ACh
  15. Neostigmine
    a carbamate, reversible inhibitor of ACh esterase; used as a ruminatoric (given to cows to stimulate digestion)
  16. Paraxon, Malaoxon
    organophosphorus insecticides, irreversible ACh esterase inhibitors; no therapeutic use
  17. Serious toxic reactions to muscarinic agonists can be treated with _________
    atropine sulfate (SQ or IV)
  18. Mechanism of Action of Muscarinic Receptor Antagonists
    competitive blocking of muscarinic receptors at the neuro-effector sites on smooth muscle, cardiac muscle, gland cells, in the CNS with little blockade of the effects of ACh at nicotinic receptor sites
  19. Blocking Muscarinic Receptors (Antagonists) causes:
    drying of secretions, inhibit digestion, increase heart rate, inhibit sweating
  20. Muscarinic Receptor Agonists and their therapeutic uses
    Atropine: stimulate heart by blocking vagus nerve; used during surgery to dry secretions

    aminopetamide: dry secretions
  21. Endogenous sympathomimetic drugs include
    epinephrine (adrenaline), norepinephrine (noradrenaline), dopamine
  22. Epinephrine- Pharmacological Effects
    beta1: increase heart rate

    beta2: bronchodilator
  23. Norepinephrine- Pharmacological Effects
    more powerful activator of alpha1 receptors than epinephrine, weaker activaor of beta2 receptors

    increases blood pressure; not useful bronchodilator

    can be used to treat hypotension
  24. Dopamine- Pharmacological Effects
    at low doses, activation of D1-receptors in the renal, coronary, and mesentric beds lead to vasodilation

    at higher doses, dopamine can stimulate cardiac beta1 receptors leading to a positive inotropic and chronotropic effects

    used in treatment of severe CHF
  25. Non selective beta agonists
    include: epinephrine, ephedrine, isoprotrenol

    used in emergencies to stimulate heart rate in cases with bradycardia or heart block
  26. Beta2 Selective Agonists
    Terbutaline; in treatment of asthma (allergic or exercise)
  27. alpha1 selective agonists
    • -nasal decongestants in humans
    • -constrict bood vessels in nasal tissues leading to decreased blood flow, decreased fluid accumulation in nasal tissues
  28. alpha2 selective agonists
    includes: xylazine, detomidine, and Medetomidine

    decrease in central sympathetic activity which give sedation and analgesia, they produce good muscle relaxation
  29. alpha-adrenoceptor blockers
    used primarily in humans to lower blood pressure
  30. beta-adrenergic receptor blockers
    blocking of beta1 receptors leads to slowing of heart rate and decreasing myocardial contractility

    blocking of beta2 receptors has little effects on pulmonary function, bronchoconstriction
  31. non selective beta-blockers
    reversibly block beta1 and beta2 receptors with no selectivity towards either subtype; propranolol

    -carvedilol: some alpha1 blocking activity to decrease blood pressure
  32. beta1 selective blockers
    metoprolol, acebutolol

    do no affect the lungs