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71 Cards in this Set
- Front
- Back
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What is the predominant innervation in the heart?
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dual innervation but parasympathetic dominates
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What organs receive only sympathetic innervation?
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Adrenna Medulla
Kidney pilomotor mucles sweat gland and Blood pressure |
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What are examples of local mediators that don't enter the blood stream because they are removed too quickly?
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Histamine and prostaglandins
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What receptors are coupled to ion channels.
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Cholinergic (ACh) Nicotinic receptors
GABA receptors Cause changes in membrane potential or ionic concentration within a cell |
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What are the receptors coupled to adeny cyclase?
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B-Adrenoreceptors
a2=Adrenoreceptors ATP->cAMP causes protein phophorilation and intracellular effects |
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What receptors are coupled to diacylglycerol and inositol triphospate?
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a1-adrenoreceptors and
Cholinergic (Ach) Muscarinic (Parasympathetic) causing protein phospoirlation and increased intracellualr calcium |
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What are the 6 steps of neurotransmission in the cholinergeic neuron?
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Synthesis of Acetylcholine
Storage of Acetylcholine Release of Acetly choline Binding to postynaptic receptor Degridation of Acetlycholine Recycling of Choline |
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What are the inhibitors/stimulators of synthesis of acetylcholine
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-hemicholinium
+Choline actyl trasferase catalizes choline and acetyl CoA to form acetlycholine |
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What is the degridation molecule for acetylcholine?
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cholinesterase found in the synaptic cleft
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What are the two cholinergic receptors?
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Muscarinic and Nicotinic
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What are the direct acting cholinergic agonists?
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Acetylcholine
Bethanechol Carbachol Pilocarpine |
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What are the indirect (reversible) acting cholinergic agonists?
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Edrophonium
Neostigmine Physostigmine Pyridostigmine |
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What are the indirect (irreversible) acting cholinergic agonists?
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Echothiophate
Isoflurphate |
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What drug will reactivate acetyl-choline esterase?
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Pralidoximine
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M1 & M3 use what signaling pathway?
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G q/11 -protein coupled, stimulate phospolipase C, producing IP 3 and DAG, which causes Ca ++ increase and depolarization
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Where are M1 receptors found?
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M1 receptors are found in the primarily in the CNS, and in exocrine glands, particularly gastric parietal cells
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Where are M2 receptors found? What do they do?
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M2 receptors are found in heart, some smooth muscle, and presynaptically on neurons
They slow the heart and decrease neurotransmitter release |
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What signaling pathway do M2 receptors use?
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G i /G o -protein to inhibit adenylyl cyclase, reducing cAMP,
open K + channels, hyperpolarizing cells |
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Where are M3 Receptors found? What do they do?
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M3 receptors are found in some exocrine glands, smooth muscle and endothelium. They stimulation increases contraction in smooth muscle, and increases secretions
from salivary gland |
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Describe Nicotinic and Muscarinc Receptor affinity for nicotine and muscarine
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Muscarinic has high affinity for muscarine and weak affinity for nicotine. The opposite is true for nicotine.
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True or False: The nicotinic receptors of the autonomic ganglia are different than the nicotinic receptors of the neuromuscular junction.
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True:
That is why you need hexamethonium to block the ganglionic receptors while tubocurarine for the NMJ |
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What are the actions of Acetylcholine?
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Decrease heart rate and CO
Decrease blood pressure Increases salivary secretions stimulates intestinal secretions and motility Increases the tone of detrusor |
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What effects does Acetylcholine have on the eye?
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stimulates the ciliary muscle to contract for near vision
stimulates the constriction of the pupillae sphincter muscle for meiosis (cnstriction of the mupil) |
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What type of drug is Bethanicol? What is the duration of action?
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Direct cholinergic agonist will exclusive activity on muscarinics. Not broken down by ach-esterase
1 hour duration |
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What are the theraputic applications for bethanicol?
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used to stimulate an atonic bladder particularly in postpartum or posoperative (noobstructive) urinary retention
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What are the adverse effects of bethanicol?
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Generalized cholinergic stimulation:
-Sweating -Salivaton -flushing -decreased blood pressure -nausea -abdominal pain -diarrhea and -bronchospasm -meosis |
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What type of drug is Carbachol? What is the duration of action?
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Cholinergic agonist that acts on M and Nicotine receptors
poorly broken down by ach-esterase 1 hour effective |
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What are the theraputic applications for Carbachol?
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Since it also stimulates nicotinic receptors it can cause Epi to be release from adrenal medula and have impact on the cardiovasucalr system. It is reserved for use in the eye where it acts like Ach causing miosis and decreases interocular pressure
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What are the adverse effects of Carbachol?
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When used opthalmaologically as indicated there are little to no side effects
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What type of drug is Pliocarpine? How long does it work?
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Cholinergic agonist
1 Day |
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What is the mechanism of action of Pliocarpine?
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It exhibits muscarinic activity and is much less potent then its derivatives. Applied to the cornea it causes rapid miosis and contraction og the ciliary muscle. It is apotent stimulator fo sweat, tears and salive, but isn't used for that purpose
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What is the therapeutic use of Pliocarpine?
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DOC for emergency lowering of the intraoccular pressure in both narrow (closed angled) and wide (open angled) glaucoma. It opens the meshwork in Schlemms canal and causes immediate drop in pressure.
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What are the adverse effects of Pliocarpine?
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It can enter the brain and cause CNS disturbances
It stimulates profuse sweating and salivation |
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What is type of drug is physostigmine?
How long does it work? |
It is a reversible substrate for acetocholinesterase which allows the potentiation of cholinergic activity throught the body. Effects last 2-4 hours
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What are the theraputic uses of phyostigmine?
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increase bowel and bladder motility
-glaucoma treatment in the eye (though pliocarpine more effective) -Due to it systemic range it can be used to treat oversoses of anticholinergic drugs like atropine, phenothiazines and tricyclic antidepressants |
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What are the adverse effects of phyostigmine?
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It can enter and stimulate teh CNS so it can lead to convulsions if high does are used.
bradycardia inhibition of ach-estase at skeletal muscle junction can cause paralysis of the muscle, but this is rare with theraputic doses |
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What type of drug is Neostigmine? How long does it last?
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Like phyostigmine, but us more polar so it doesn't enter the CNS
Can cause contractility then paralysis on skeletal muscle since it is stronger then phyostigmine. 2-4 hour shelf-life |
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What are the thereaputic indications fpr Neostigmine
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Symptomatic treatment of Myasthenia Gravis
Can stimulate bladder and GI Used as antidote for tubocarine and other competitive neuromuscular blocking agents |
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What are the general adverse effects of cholinergic stimulation?
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Salivation
Flushing decreased blood pressure nausea abdominal pain diarrhea broncospasm |
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What is Pyridostigmine?
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another cholinesterase inhibit that is used in the chronic management of myasthenia gravisl duration of action is 3-6 hours as opposed to that of neiostigmine (2-4)
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What is Edrophonium used for?
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Dx of Myasthenia gravis. IV injection will improve muscle stregnth. Short duration of action (10-20 minutes).
If too much given can provoke cholinergic crisis and atropine is the antidote. |
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What type of drug is isoflurophate?
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It is an organophospahte that binds to the serine-OH in the active site of acetylycholineesterase. Aging to the bond occurs within a few hours making pralidoxime [PAM] (a reactivator) ineffective. This drug causes miosis and can be used for chronic tx of open angle glaucoma.
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What are the actions of Isoflurophate?
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Generalize cholinergic stimulation, paralysis of motor function causing breathing difficulties and convulsions (It is a military nerve agent). Atropine in high doeses can reverse somemuscarinc and central effects.
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What are some antimuscarinic agents?
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Atrotpine
Ipratropium Scoolamine |
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If a drug is anticolinergic, what receptors is it blocking?
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Muscarinc and Nicotinic
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What type of drug is Atropine? How long does it last?
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A belladonna alkaloid that is an antimuscarinic where it binds competitively blocking Acetylcholine
It lasts 4 hours when systemic, but lasts days in the eyes |
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What is atopines action in the eye?
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Blocks all cholinergic activity resulting in mydrassis (dialation) and cycloplegia (inability to fcus near) In patients with interocular glaucoma this can cause IO pressure to rise dangerously.
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What is atropines effect in the GI system?
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It its an antispasomidic to reduce activity of the GI Tract. It has little to no effect on the production og HCL so it isn't effective in promoting the healing of a gastric ulcer.
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What is atropines effect on the urinary system?
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reduces hypermotility of the bladder
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What is atropine's effect on the cardiovasular system?
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Dose dependant
Low dose- decreases cardiac rate (bradycardia) High does- the cardiac receptors on the SA node are blocked and a mild tachycardy can occur Will dialate cutaneous vascualture at toxic levels otherwise blood pressure not effected |
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What is atropines effect on secretions?
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it blocks salivary glands causin xerostomia. also blocks sweat and lacrimal glands. May make body more difficult to cool and can cause increase in body temperature.
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How is atropine used theraputically?
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in the eye it is mydratic and cycloplegic so an accurate measurement of refractive erros can be made. Can cause attack in individuals with glaucoma
In GI/Bladder it is antispasmodic Used as ANTIDOTE for cholinergic agonists Antisecretory agent to dry secretions prior to surgery |
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What are the side effects of Atropine?
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Hot as a hare
Dry as a bone Red as a beet Blind as a bat Mad as a hatter |
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What type of drug is scopolamine?
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Similar drug to atropin but greater CNS effect and longer duration
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What are the therapeutic uses for scopolamine?
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Motion sickness
but it has side effects of sedation and short term memory loss |
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What type of drug is ipratropium?
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Muscaringi blocker
used to treat asthama and COPD patients that are unable to take adrenergic agonists |
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Describe the mechanism of ganglionic blockers.
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They work on nicotinic receptors blocking the ionic channels and are not specific for either sympathetic or parasympathetic.
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What are the effects of Nicotine?
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increasei n blood pressure and cardiac rate due to the release od transmitter from the adrenergic terminals and adrenal medulla
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What is trimethophan indicated for?
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it is a ompetitive nicotinic ganglionic blocker and used IV fro the lowering of blood pressure
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What is the mechanism of non-depolarizing neuromuscular blockers?
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At low doses they combine with the nicotinic receptor and prevent the binding of Ach which prevents depolarization. There actions can be overcome
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What are the two types of neuromuscular junction blocking agents?
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non-depolarizing, competitive antagonists (d-
tubocurarine) depolarizing blockers (Succinylcholine) |
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What drugs are used to reverse the action of the non-depolarizing blockers?
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Cholinesterase inhibitors such as neostigmine
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What do d-Tubocurarine, pancuronium and doxacurium have in common?
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slow onsets (4-6 min) and long
durations of action (2-3 hr); are difficult to remove (metabolized by kidney) and are infrequently used |
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What is the duration of action for Vecuronium, atracurium, and cisatracurium
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intermediate durations of action (20-40
min), with an onset of 2-4 min. |
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What is is the most commonly used non-depolarizing neuromuscular blocking agent due to the fact that it is spontaneously hydrolyzed, and has low toxicity.?
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Cisatracurium
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Describe the absorption of the The non-depolarizing neuromuscular blockers.
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They are highly ionized, so will NOT be absorbed orally. They must be injected IV
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Will drugs that are highly ionized be able to cross the CNS?
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NO
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What muscles are paralyzed first with a nondepolarizing neuromuscular blocker? Which resume function first? once the effects wear off?
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Small muscles (eye, jaw, larynx) are generally affected first, followed by larger muscles (limbs
and trunk). The intercostal muscles and the diaphragm are the last to be paralyzed, and the first to recover • Recovery occurs in the reverse order of paralysis |
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Describe the "train of Four" outcome with a non-depolarizing outcome
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Nondepolarizing blockade will cause a “fade” represented by decrease in twitch height.
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Describe the "train of Four" outcome with a depolarizing outcome
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With depolarizing blockade (succinylcholine),
the size of each twitch is reduced, but there is no fade in the twitch height. |
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How do depolarizing agents in neuromuscualr cascade work?
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They depolarize initialy but the depolarizing action is prolonged, so
that subsequent release of ACh does not have any effect, since the endplate is already depolarized. With time the endplate sesensitizes. |
