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129 Cards in this Set
- Front
- Back
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What NT is predominant at the synapse b/w pre- & post-ganglionic fibers in the SyNS?
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ACh
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What NT is predominant at the synapse b/w pre- & post-ganglionic fibers in the PaNS?
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ACh
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What receptor is predominant at the synapse b/w pre- & post-ganglionic fibers in the SyNS?
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nicotinic
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What receptor is predominant at the synapse b/w pre- & post-ganglionic fibers in the PaNS?
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nicotinic
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What NT is predominant at the synapse of the post-ganglionic fiber & target in the SyNS?
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NE
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What transmitter is predominant at the synapse of post-ganglionic fibers & the target organ in the PaNS?
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ACh
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What receptor is predominant at the synapse of post-ganglionic fibers & target organ in the SyNS?
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alpha 1, alpha 2, beta 1, beta 2
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What receptor is predominant at the synapse of the post-ganglionic fibers & target organ of the PaNS?
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muscarinic
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The SyNS is _______(adrenergic or cholinergic)
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adrenergic
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The PaNS is _________ (adrenergic or cholinergic)
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cholinergic
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Alpha 1 receptors are found primarily where? (5)
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cutaneous bld vessels
eye uterus urinary sphincter CNS |
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What is the 2nd messenger at alpha 1 receptors?
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inositol phosphate (IP3)
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Alpha 2 receptors are located where? (1)
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CNS
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What is the 2nd messenger at alpha 2 receptors?
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cAMP (dec)
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Beta 1 receptors are primarily located where?
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Heart
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What is the 2nd messenger at beta 1 receptors?
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cAMP (inc)
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Beta 2 receptors are primarily located where? (6)
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bronchi
m bld vessels pancreas bladder wall uterus liver |
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What is the 2nd messenger at beta 2 receptors?
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cAMP (inc)
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Dopamine receptors are primarily found where? (3)
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CNS
kidney vasculature |
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What is the 2nd messenger at dopamine (D1) receptors?
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cAMP (inc)
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What is the 2nd messenger at dopamine (D2) receptors?
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cAMP (dec)
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What is the single receptor common to the PaNS?
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muscarinic cholinergic
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What is the effect on the eye of SyNS alpha 1 axn?
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Dilation
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What is responsible for constricting the eye?
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PaNS
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What is the effect on the heart of SyNS beta 1 axn?
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inc HR
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What is the effect on the heart of PaNS axn?
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dec HR
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SyNS alpha 1 axn has what effect on the bld vessels?
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Constricts vessels => inc BP
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SyNS beta 2 axn has what effect on the bld vessels?
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Inc bld flow to lg skeletal mm
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What effect does SyNS beta 2 axn have on the bronchi?
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dilation
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What is responsible for inc peristalsis & urination?
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PaNS effects on the GI & urinary tracts
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What effect does PaNS axn have on the exocrine gll?
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Inc secretions
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How do direct acting sympathomimetics work?
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An agonist actually binds with receptor (NT) to => axn
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How do indirect acting sympathomimetics work?
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Either inc or dec activity of nat'l NT which then => axn
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Alpha 1 drugs may be used for what (5) main axns in the CV system?
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dec hemorrhage
nasal decongestants inc BP localize drugs shock tx |
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Alpha 2 drugs may be used for what reason in the CV system?
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To dec BP
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Why would we use beta 1 drugs for effects in the CV system?
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to inc HR & strength of contraction
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Why might we use beta 2 drugs for effects in the respiratory system?
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bronchodilators
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Why would we use alpha 1 drugs for effects in the eye?
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Act as mydriatics
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We would target the alpha 1 receptor in the urethra & uterus if we wanted to do what?
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Stimulate smooth m (constrict)
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Alpha 1 drugs may be used for what effect in the CNS?
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Stimulation
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What other types of drugs besides alpha 1 would be used to stimulate the CNS?
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dopaminergic drugs
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Why might we use alpha 2 drugs for effects on the CNS?
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tranqs, analgesics
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Alpha 2 drugs essentially act by ______.
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shutting down alpha 1 activity
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SEs may be seen at the pancreas w/ what class of receptors?
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beta 2
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What kind of toxic effects could result from alpha 1 drugs used in excess?
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overstimulation of the heart (inc BP)
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Endogenous sympathomimetic NTs are ______.
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catecholamines
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Synthetic drugs tend to be less _____, but more _____.
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potent
stable |
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Substitutions on the aliphatic Cs (ethyl group) of phenyethylamine affects _____ (kinetics or dynamics)?
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kinetics
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What is the result of substituting a hydroxyl group on the ethyl group?
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inc polarity (can be used PO more efficiently)
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What is the result of substituting a methyl group on the ethyl of phenylethylamine?
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inc stability (b/c there is no MAO)
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Substitutions on the N (amine group) of phenyethylamine affects __________ (kinetics or dynamics).
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dynamics
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Substituting a methyl or larger group on the amine group of phenylethylamine will result in what?
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inc beta activity
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Changes on the aromatic ring of phenylethylamine affects _______ (kinetics or dynamics).
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both
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Dec the hydroxyl groups on the phenol of phenylethylamine would result in what?
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inc stability (no COMT) & inc alpha activity
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Rearranging the hydroxyls on the aromatic ring of phenylethylamine results in what?
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makes it beta selective
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NE prefers what receptor?
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alpha
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Epinephrine prefers what receptors?
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alpha & beta*
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Isoproterenol prefers what receptor?
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beta
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Name 2 drugs that are sympathomimetics w/ impt alpha-1 receptor axn.
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epinephrine
NE |
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What type of drugs are in the subclass of sympathomimetics that has impt alpha-1 receptor axn?
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Endogenous & nat'l substances
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Sympathomimetics that have impt alpha 1 receptor axn are used therapeutically as ____ (3).
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vasoconstrictors
mydriatics inc smooth m tone (uterus, bladder) |
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Unstable weak bases w/ impt alpha 1 activity include what 2 drugs?
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NE
epinephrine |
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Are unstable weak bases w/ impt alpha 1 activity good when given PO?
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no
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What may be a common undesired result of giving sympathomimetics that are unstable weak bases w/ impt alpha 1 activity?
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tachyphylaxis
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Is PO use possible w/ more stable alpha 1 acting sympathomimetics?
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yes
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More stable alpha 1 acting sympathomimetics are _________ (catechols or noncatechols)
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noncatechols
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Activity at what receptor is responsible for dec presynaptic outflow leading to tranq, dec BP & analgesia?
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alpha 2
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What two types of drugs may be combined w/ alpha 2 acting sympathomimetics?
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CNS drugs (e.g., anesthetics)
Other ANS drugs to dec adverse CV effects |
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Name one sympathomimetic used predominantly for its alpha 2 receptor axn.
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xylazine
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How does isoproterenol work?
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It acts as an agonist at beta receptors
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What effect does isoproterenol have at beta 2 receptors?
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bronchodilation
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What effect does isoproterenol have at beta 1 receptors?
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cardiostimulation
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What receptor would you target w/ a sympathomimetic if you wanted to stimulate the heart and open the airways?
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beta 2
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List 4 ways sympathomimetics can act by nonreceptor (indirect) mechanisms.
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1. Affect the CNS by inc NE or dopamine
2. Inhibit phosphodiesterase which leads to inc cAMP 3. Inhibit MAOs 4. Inhibit monoamine reuptake |
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What class of drugs is responsible for inc NE or dopamine & consequently affecting (stimulating) the CNS?
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C-II drugs such as amphetamines or tx of ADHD
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Name one drug that acts as an indirect sympathomimetic by inhibiting phosphodiesterase.
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theophylline
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What is phosphodiesterase responsible for?
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destroys cAMP
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How do methylxanthines affect the CNS?
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they inhibit phosphodiesterase, thereby inc cAMP at beta receptors & stimulating the CNS
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What may be an add'l effect of phosphodiesterase inhibitors at the bronchi or bld vessels?
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smooth m relaxation
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What may be one class of drugs to use in the case of pulmonary disorders to stimulate respiration?
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phosphodiesterase inhibiting sympathomimetics
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How do MAO inhibitors work?
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They dec the degradation of monoamines (NE, dopamine, serotonin)
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What are 2 clinical uses of MAOIs in dogs?
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For hyperadrenocorticism of hypothalamic-pituitary origin or for cognitive dysfxn in geriatrics
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What drugs are used for CNS disorders, including narcolepsy & behavioral aberrations?
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monoamine reuptake inhibitors
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List 3 types of agents involved in monoamine reuptake inhibition.
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tricyclic antidepressants
SSRIs Dopamine reuptake inhibitors |
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What are some disadvantages of using monoamine reuptake inhibitors?
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expensive
take days to weeks to be effective have notable SEs (anxiety & CV effects) |
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How does cocaine work therapeutically?
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inhibits catecholamine reuptake w/ fast onset & therefore may be used as a topical vasoconstricting local anesthetic
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Sympatholytics are what kind of drugs?
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antiadrenergics
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How do sympatholytics generally work?
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as antagonists that either directly act on a receptor or by other mechanisms
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What are some clinical uses of sympatholytics?
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dec BP
dec ocular press dec CNS fxn dec HR |
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What are some possible SEs of sympatholytics?
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inc peristalsis
dec ejaculation inc Na+ retention |
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What may be one reason to use a sympatholytic that acts predominantly by blocking alpha 1?
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to tx hypertension
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Alpha 2 blockers are used as antidotes of what?
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alpha 2 agonists
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When might you use direct antagonists at beta receptors?
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to dec HR & cardiac output
(as antiarrhythmics & hypotensives) |
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When may heart fialure occur w/ direct beta receptor antagonists?
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With parenteral admin or w/ sudden w/drawal after long-term PO use
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What kind of drugs might be used topically to lower ocular pressure?
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direct antagonists at beta receptors
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What is a problematic SE of direct beta receptor antagonists?
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inc airway resistance
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(T/F) Direct antagonists of beta receptors are highly protein bound.
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T
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Where are direct antagonists at beta receptors typically metabolized?
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in the microsomes of the liver (by microsomal Zs)
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Name one drug that can be used as a nonselective beta 1, beta 2 blocker.
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propranolol
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Why might we use a non-selective beta blocker as opposed to specific beta 2 blockers?
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We what to avoid bronchoconstriction and they are less expensive
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How does propranolol work?
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It's a competitive antagonist for NE at beta 1 (heart) & beta 2 (bronchioles & some bld vessels) receptors.
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What are the 3 mechanisms by which sympatholytics can act indirectly?
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1. By dec precursors for NE synthesis (anti-dopaminergic drugs)
2. by dec NE rel (esp by blocking Ca++) 3. as alpha 2 agonists dec available NE (tranqs) |
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What is the general effect of all indirectly acting sympaholytics?
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these dec availability of dopamine or NE at postganglionic sites
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Give two examples of antidopaminergic cmpds.
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acepromazine
metoclopramide |
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How do antidopaminergic cmpds work?
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As antagonists or partial agonists at the dopamine receptor to dec availability of dopamine at postganglionic sites
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What are the 2 primary uses of antidopaminergic cmpds?
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tranqs
antiemetics |
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How might a drug dec available NE?
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by Ca++ channel block
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Why might we use Ca++ channel blockers?
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For their CV effects (to tx hypertrophy, arrhythmias, hypertension)
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What kind of drugs can be microsomal enzyme inducers?
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Ca++ blockers
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(T/F) Indirect acting sympatholytics that dec available NE by blocking Ca++ channels are readily absorbed & highly protein bound.
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F: They are poorly absorbed, but they are >90% protein bound
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Alpha 2 agonists (inc/dec) sympathetic outflow
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dec
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Give one example of a drug that acts as an indirect sympatholytic by dec sympathetic outflow.
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xylazine
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In general alpha 2 agonists are used as ____ (4).
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tranqs, antihypertensives, analgesics, emetics
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What are the general effects of parasympathomimetics?
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Stimulation at muscarinic receptors (some also stimulate nicotinic receptors)
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What are some uses of parasympathomimetics?
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miotics
tx of certain types of glaucoma tx of smooth m atony urine retention neuromuscular dz anthelmintics & insecticides antidote |
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By what mechanism do parasympathomimetics act indirectly?
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via inhibition of ACh degradation
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What is one SE of parasympathomimetics?
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oversecretions
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Give two examples of drugs that have direct action at muscarinic receptors as parasympathomimetics
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acetylchoine
metoclopramide |
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What is the mechanism of axn of esters & amide ACh-like structures as parasympathomimetics?
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polar molecules bind to anionic site of ACh receptor
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Metaclopramide (inc/dec) ACh in the GI tract.
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inc
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How are ester & amide ACh-like parasympathomimetics metabolized?
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by hydrolysis of ester or smide drugs
conjugated in liver excreted in urine |
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Give one example of a plant alkaloid that is used as a direct acting parasympathomimetic.
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pilocarpine
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What is the primary product in use for glaucoma?
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pilocarpine
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How does pilocarpine work?
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it is a miotic
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How do cholinesterase inhibitors work?
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they inhibit ACh hydrolysis
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What are the two subtypes of indirect agonist parasympathomimetics?
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short-acting reversible
long-acting irreversible |
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Long-acting irreversible cholinesterase inhibitors are what class of drugs?
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OPs
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How does neostigmine work?
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it's a carbamate that reversibly binds to ChE
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What are the primary uses of carbamates (such as neostigmine)?
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Tx of NM dz
miotics (tx glaucoma) antidotes for reversible NM blockers insecticides, antiprotozoal drugs for alzheimer's in Hu |
