Pharmacology Exam III (Fall 2006)

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What are the two ways that drugs can act?: 1. Direct Acting - act in the same place a transmitter binds. (agonist/antagonist)
2. Indirect Acting - inhibit metabolism of neurotransmitters, keeps transmitter in synapse longer.
What receptors does the Parasympathetic Nervous System correspond with?: Cholinergic
What receptors does the Sympathetic Nervous System correspond with?: Adrenergic
What does the Autonomic Nervous System control?: Control of Heart Rate, control of exocrine glands, influence on certain endocrine glands, altered tone in almost all smooth muscle, effects on metabolism.
Conservation of energy, elimination of waste, essential for life, localized activation, leading to growth, acetycholine: Parasympathetic
Cardiovascular control, defense activation, not essential for life, diffuse activation, mobilization of energy, "fight or flight", Norepinephrine: Sympathetic
Blocks Muscarinic Receptor: Atropine
Blocks Nicotinic Receptor: Hexamethonium
Blocks Nicotinic Receptors: d-Tubocuarine
A diverse group of chemical substances that mimic the actions of Ach: Cholinomimetics
Bind directly to and "activate" Ach receptors: Direct-acting cholinergic Agents
Ach, methacholine, carbachol, bethanechol: Choline Esters
Pilocarpine, muscarine, nicotine, arecoline, lobeline: Cholinomimetic Alkaloids
Drugs and other chemical agents in this group evoke a cholinomimetic effect by inhibiting the hydrolysis of endogenous acetylcholine: Cholinesterase Inhibitors
Physostigmine, neostigmine, ambenonium, pyridostigmine: Reversible cholinesterase Inhibitors
Echothiophate (phopholine), malathion, parathion, sarin, soman: Irreversible Cholinesterase Inhibitors
Direct Cardiac effects of Ach: Decrease the rate of SA node depolarization, delayed AV conduction, decrease in contractile force of ventricles. However, direct effects my be masked by homeostatic reflex-induced changes
Direct GI effects of Ach: Enhanced intestinal motility and peristalsis, increase exocrine secretions, relaxation of most sphincter muscles.
Direct ocular effects of Ach: Miosis (contraction of the iris sphincter muscle results in pupillary constriction), lens fixed for near vision, increased drainage of aqueous humor
Direct pulmonary effects of Ach: Bronchoconstraction
Direct effects of Ach on Urinary Bladder: Contraction of bladder detrusor muscle, relaxation of trigone and sphincter muscles, promotion of bladder emptying.
Direct effects of Ach on sweat, nasopharygeal, lacrimal glands: Increased secretion
Why are the systemic uses of cholinomimetics limited?: Becuase of the unpleasant side effects
What are some medical uses of cholinomimetics?: To facilitate urination in "hypotonic bladder" following spinal cord injury, in non-obstructive urinary retension, and to enhance peristalsis after surgury
How many known multiple molecular subtypes of muscarinic receptors are there?: Five m1-m5
What are some possible side effects to cholinomimetics?: Cardiovascular - flushing, headache, hyptotension, heart rhythms
GI - cramps, nausea, belching, diarrhea
Respiratory - asthma attack, breathing difficulty
Hypersecretion - salivation, drooling, excessive sweating
Physical obstruction, peritonitis, bronchial asthma, peptic ulcers, cardiovascular disease: Contraindications to using cholinomimetics
What is the specific antidote for toxic reactions caused by excessive activation of muscarinic receptors?: Atropine sulfate (parentally)
What occurs if pilocarpine is given systemically?: Prominent muscarinic actions occur such as sweating, salivation, cramping, and diarrhea
How does Pilocarpine help patients with wide-angle glaucoma?: It improves drainage of aqueous humor by reducing outflow resistence.
How does Pilocarpine help patients with acute angle closure glaucoma?: By contracting the ciliary muscle and inducing miosis, the iris muscle is mechanically pulled away from the trabecular meshwork.
True or False? Pilocarpine is long-lasting.: False.
It is short-lasting and drug must be applied repeatedly.
What are the cholinomimetic miotics?: 1. Direct acting: pilocarpine, carbachol, Ach
2. Cholinesterase inhibitors: physostigmine, echothiophate
What are some adrenergic glaucoma drugs?: epinephrine, dipivefrine, apraclonidine
How do Beta adrenergic blockers treat glaucoma?: Beta-blockers reduce the formation of aqueous humor.
Timolol, betaxolol, carteolol, levobunolol: Beta-adrenergic blockers for glaucoma
What glaucoma drugs can be given systemically to decrease the formation of aqueous fluid by ciliary epithelial cells?: Carbonic anhydrase inhibitors
What are some carbonic anhydrase inhibitors?: Acetazolamide (Diamox), dichlorophenamide (Daranide), methazolamide (Neptazine), and dorzolamide (Trusopt) [for topical use]
What is a Prostaglandin agonist?: Latanoprost (Xalatan)
How does Xalatan work?: It is a structural analog of PGF and it improves drainage.
What type of drugs induce fluid withdrawl from eyeball by increasing osmolarity of blood?: osmotic diuretics
What are some osmotic diuretics?: Mannitol, isosorbide, glycerin
What cholinesterase enzymes are found widely distributed in the body except around nerve endings?: Plasma cholinesterase
What cholinesterase enzymes are found localized in and around nerve terminals of all cholinergic nerves?: Acetylcholineresterases
Alkaloids: Tertiary amine and Synthetic quaternary amines: Reversible enzyme Inactivators (C17)
Form a stable covalent complex with enzyme resulting in a long duration of action; organophosphates, thiophosphate insecticides, and chemical warfare agents (c18): Irreversible Enzyme Inactivators
What are used to improve skeletal muscle weakness that characterize myastenia gravis?: Cholinesterase inhibitors
What is the basic pathophysiology of myastenia gravis?: A chronic autoimmune disease of skeletal muscle transmission.
What are some approaches to treat myasthenia gravis?: Increase local concentrations of Ach at myoneural junctions, decrease anti-Ach receptor antibody titer.
Surgury (thymectomy)
Plasmapheresis
A very short acting Che inhibitor with several medical uses, shows improvement in muscle strength after small does.: edrophonium (Tensilon)
What are some other uses for Tensilon?: Antidote for "curare" overdoes to hasten post-surgical recovery from muscle paralysis. Antiarrhythmic to control certain cardiac rhythym abnormalities.
What are some general treatment approaches in Cholinesterase Inhibitor Toxicity?: Decontamination, Respiratory Support Procedures, Seizure Control, Treat Circulatory Shock, atropine sulfate, cholinesterase reactivator (pralidoxime chloride [protpan])
What are some Cholinesterase Inhibitors for the treatment of Alzheimer's disease.: Tetrahydroaminoacridine (Cognex)
Donepezil (Aricept)
What are Antimuscarinic Drugs?: These are drugs that inhibit the actions of Ach on tissues that receive innervation by postganglionic cholinergic nerves, as well as on cells lacking cholinergic innervation but expressing muscarinic cholinergic receptors.
Naturally occurring "poisons" in various plants: Belladonna Alkaloids
Comes from Deadly Nightshade: Atropa Belladonna
Immson Weed; Stinkweed produce this alkaloid: Datura Strammonium
Comes from Henbane: Hyoscyamus niger
Semisynthetic derivatives of Atropine: Homatropine methylbromide, methylatropine nitrate, methscopolamine bromide
Where does Atropine bind?: Muscarinic receptors located on cell membranes in exocrine glands, smooth muscle cells, cardiac cells, neurons, etc..
What receptors does Atropine have a high affinity for, but a lack of intrinsic efficacy, and non-selective.: Muscarinic
What receptors does Atropine have insignificant effects at usual doses?: Nicotinic
True or False? Atropine acts as a competitive antagonist of muscarinic receptors?: True
Tachycardia, vasodilation, and increase in blood pressure: Effects of a large dose of atropine on Cardiovascular system
Iris sphincter relaxes-pupil dilates Cycloplegia-paralysis of accomodation Increase in intraocular pressure may occur: Effects of a large dose of atropine on ocular system
Secretions are inhibited, xerostomia, decrease in GI motility: Effects of a large dose of atropine on GI tract
Decrease sweating, decrease mucous in nasopharynx and bronchi: Effects of Atropine on exocrine glands
Bronchodilation, decrease tone of bladder wall, effects on biliary tract and uterus: Effects of Atropine on other smooth muscles
CNS excitement: restlessness, irritability, disorientation, hallucinations, seizures, etc.: Effects of Atropine on CNS
Used to prevent motion sickness.: Transdermal scopolamine
What are the methods to treatf Atropine Poisoning?: 1. removal of unabsorbed drug
2. support vital functions: respiration, maintain CV function
3. Physostigmine parentally
4. Sedatives to counteract seizures
5. Symptomatic therapy for fever etc.
What are some derivatives of Atropine that do not show muscarinic activity?: Diphenhydramine is an antihistimine
Haloperidol is an antipsychotic
imipramine is a try-cyclic antidepressant
Lithium Salts are sued to treat manic depression (see more on C 31)
What are drugs that interrupt neurotranmission at autonomic parasympathetic and sympathetic ganglia?: Ganglionic Blocking Agents (GBA)
GBAs can be observed as a type of anticholinergic drug wtih activity on nicotinic receptors located in autonomic ganglia throughout the body. But where are GBAs less potent?: They are less potent in blocking neurotransmission at the post-ganglion at skeletal muscle myoneural junctions.
Ganglionic blocker blocks the effects of nicotine?: Yes
Nicotine is a depolarizing agent at high doses, how does it work?: Produces a persistent depolarization of the synaptic cell membrane, thus preventing subsequent impulses from being propogated?
Hexamethonium and trimethaphan are Non-depolarizing agents. How do they work?: They stabilize the post-synaptic cell membrane by competitive nicotinic receptor blockade.
What are some therapeutic uses of GBA?: Hypertensive crisis, produce "controlled" hypotension, and reduce bleeding during surgury, in autonomic "hyperflexia", and in tobacco smoking cessation
What is the major action of neuromuscular blocking agents?: These drugs have the ability to interrupt cholinergic neurotransmission at skeletal muscle neuroeffector juntions.
Classical example of NMBA: d-Tubocurrarine "curare"
What are two examples of NMBA depolarizing agents?: succinylcholine and decamethonium
What are the two types of NMBA?: Competitive blockers and depolarizing blockers
What is the sequence of muscle paralysis for tubocarrare?: 1. Most sensitive are small rapidly moving muscles (ie fingers, eyes)
2. Limbs, neck, trunk muscles
3. Intercostals
4. Diaphragm
What are some side effects to NMBA?: Prolonged apnea, Cardiovascular collapse (severe hypotension), malignant hyperthemia
Is norepinephrine more prominent than epinephrine?: yes 10:1
What are a large group of chemical agents that mimic autonomic sympathetic nerve activation and hormonal secretion of epinephrine?: Sympathomimetic drugs
(Alpha adrenoceptors) Peripheral excitatory activity on vascular smooth muscles: Vasoconstriction
(beta-2-adrenoceptors) peripheral "inhibitory" activity on different smooth muscles: Vasodilation, bronchodilation, uterine relaxation
(beta-1 adrenoceptors) cardiac "excitatory" effects: Increased heart rate, increased mechanical force development
(beta adrenoceptors) metabolic activation: increase rate of glycogenolysis (liver/muscle)
(beta-3 adrenoceptors) metabolic activation: increase lipolysis from adipose tissue
(alpha/beta adrenoceptors) "endocrine" actions - modulation of hormonal secretion: Insulin, renin, pituitary hormones
CNS "excitatory" activity - behavioral effects, mood alterations (adrenoceptors): decrease appetite, increase wakefulness, respiratory stimulation, euphoria
What are the steps in the biosynthesis of catecholamines?: Tyrosine--->Dopa--->Dopamine
--->Norepinephrine------->Epinephrine
Increasing the bulk size of alkyl substitution on the amino group generally results in increased beta or alpha adrenergic activity?: Increase in Beta
Generally, the lesser the alkyl substitution on the amino group, the greater the selectivity for alpha or beta adrenoceptor activity?: Alpha
Maximal potency depends on the prescence of what groups at the 3 and 4 positions on the aromatic ring?: Hydroxyl
Substitution on what blocks oxidation by MAO, thus prolonging the duration of action of noncatecholamines: The alpha-carbon atom
Binds to adrenergic receptors to evoke agonist effect in target tissue; ie phenylephrine and isoptorerenol: Direct-acting sympathomimetic
Induces the release of norepinephrine from sympathetic nerves; ie tyramine and hydroxyamphetamine: Indirect-acting "sympathomimetic"
Compound has both direct and indirect acting abilities ie ephedrine, amphetamine: Dual-acting sympathomimetic

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