Drugs Affecting the Sympathetic NS Flashcards
adrenergic agonists are aka
sympathomimetics
adrenergic agonists are drugs that
stimulate the SNS
sympathetic NS
describe the pre/post ganglionic fibers of the sympathetic NS
pre-ganglionic: short
post-ganglionic: long
where does the ganglion reside in the sympathetic division?
closer to the spinal cord or CNS
give 2 examples of SNS neurotransmitters
- norepinephrine
- epinephrine (catecholamines)
what is the vital requirement for the release of neurotransmitters?
A Ca2+ influx into the axon terminal
where are Beta-adrenergic receptors found?
on the postsynaptic effector cells
Beta 1 is primarily located in the
heart
Beta 2 is primarily located in
smooth muscle of
- bronchioles
- arterioles
- visceral organs
where are alpha- adrenergic receptors found?
pre & postsynaptically
alpha 1 is found on
postsynaptic effector cells
- smooth muscle of sphincter (GI & bladder)
- blood vessels
alpha 2 is found on
presynaptic nerve endings and the central nervous system
action of specific adrenergic receptor sites through agonist binding
alpha 1
- vasoconstriction
- increase BP
- increase muscle sphincter tone
action of specific adrenergic receptor sites through agonist binding
alpha 2
- inhibits NE & insulin release from the presynaptic terminals
action of specific adrenergic receptor sites through agonist binding
beta 1
- increased heart rate through SA and AV nodes
- increase force of myocardial contraction
action of specific adrenergic receptor sites through agonist binding
beta 2
- vasodilation = decrease in BP
- bronchodilation
- increase rate and force of heart contraction
- decrease GI tract motility
direct acting sympathomimetics bind directly to the
receptor for a physiological response
indirect-acting sympathomimetics stimulate the release of _________
catecholamines
catecholamines are released from…
storage sites in nerve endings
after indirect-acting sympathomimetics stimulate the release of catecholamines they
bind to receptors
what stimulates the release of norepinephrine from nerve endings to create a stimulating effect?
amphetamines
what drugs inhibit the reuptake of norepinephrine into the axon terminal?
- cocaine
- tr-cyclic antidepressants (TCA)
drugs inhibiting the reuptake of norepinephrine into the axon terminal results in a
prolonged stimulant effect
mixed-acting sympathomimetics can be described as both a
direct stimulation of receptor sites and release of catecholamines from nerve endings