Adrenergic and Cholinergic Receptors Flashcards
red info and some theory. complete
3 visceral tissues (visceral targets) the ANS controls
smooth muscle; cardiac muscle; glands
pre-ganglionic fibres of the ANS (SNS and PNS) release this NT at the ganglia; the NT binds to this type of receptors
acetylcholine (ACh); nicotinic
post-ganglionic fibres of the SNS release this NT at the ganglia; the NT binds to this type of receptors
norepinephine (NE); adrenergic
post-ganglionic fibres of the PNS release this NT at the ganglia; the NT binds to this type of receptors
acetylcholine (ACh); muscarinic
SNS nucleus is located in _____; ganglion in ______ axon varicosities in _________
nucleus in spinal cord; ganglia bilaterally adjacent to vertebral column; axons in target tissue
PNS nucleus is located in _____; ganglion in ______ axon varicosities in _________
brainstem and medulla; ganglia in target tissue; axon in target tissue
are nicotinic receptors ligand-gated ion channels or GPCRs
ligand-gated ion channels
are adrenergic receptors ligand-gated ion channels or GPCRs
GPCRs
are muscarinic receptors ligand-gated ion channels or GPCRs
GPCRs
4 products of adrenal glands
mineralocorticoids, glucocorticoids, androgens, epinephrine and norepinephrine (remember salt, sugar, sex, stress)
epinephrine has high affinity for which receptors
alpha and beta adrenergic receptors
norepinephrine has high affinity for which receptors
alpha adrenergic receptors, weaker affinity for beta adrenergic receptors
name 5 target tissues of SNS
eye (+ smooth muscle around eye), salivary glands, arterioles, lungs, heart, stomach, GIT, kidney, bladder
name 5 target tissues of PNS
eye (+ lacrimal gland), salivary glands, lungs, heart, GIT, bladder, penis, prostate
does the PNS directly affect vascular smooth muscle
no
true or false: the heart has both sympathetic and parasympathetic innervation
true
true or false: blood vessels have both sympathetic and parasympathetic innervation
false, only has sympathetic innovation (except in erectile tissue)
name a major function of alpha 1 adrenergic receptor activation on the cardiovascular system
vasoconstriction
name a major function of alpha 2 adrenergic receptor activation on the cardiovascular system
direct blood vessel effect of vasoconstriction at first, then presynaptic effect of vasodilation
name a major function of beta 1 adrenergic receptor activation on the cardiovascular system
increased cardiac output
name a major function of beta 2 adrenergic receptor activation on the cardiovascular system
vasodilation of skeletal muscle and heart; bronchodilation
name a major function of muscarinic adrenergic receptor M2 activation on the cardiovascular system
decreased cardiac output
name 4 physiological effects of parasympathetic overstimulation
diarrhea, urination, mitosis, bronchorrhea, bradycardia, emesis, lacrimation, lethargy, salivation, sweating
Horner’s syndrome results from the loss of what
loss of sympathetic supply to head and neck
drugs that act similarly to endogenous catecholamines (norepinephrine, epinephrine) are called
sympathomimetics or adrenergic agonists
drugs that act similarly to acetylcholine are called
parasympathomimetics or cholinergics or cholinoreceptors stimulants
name 2 irreversible acetylcholinesterase (ACh) inhibitors
organophosphates and sarin nerve gas
this drug is a reversible inhibitor of acetylcholinesterase, so results in increased breakdown of Achieving at synaptic cleft, and is used to increase gut motility and myasthenia gravis
neostigmine (cholinergic)
these 2 drugs are competitive muscarinic antagonists, dose-dependent, and are used for emergency treatment of arrhythmias, bronchodilators, ophthalmic exams
atropine and glycopyrrolate (anticholinergics)
which drug crosses BBB to lesser extent and so has fewer CNS effects: atropine or glycopyrrolate
glycopyrrolate does not cross BBB as much so has fewer CNS effects
this drug is only used in horses in Canada, has similar effects to atropine, and is used for gas/spasmodic colic, acute equine asthma treatment, and as rectal exams
N-butylscopolammonium bromide / hyoscine butyl bromide (anticholinergic)
do alpha 2 agonists increase or decrease cardiac output
decrease cardiac output (so they are good premeds for anesthesia and standing procedures, since they are sedatives and analgesics, but they are bad for CV compromised patients)
how do alpha 2 agonists provide sedation? provide anesthesia?
sedation due to inhibition or norepinephrine release in brainstem; anesthesia due to reduced NT release and signal transmission in afferent pathways
how do alpha 2 agonists reduce cardiac output
initial vasoconstriction effect causes reflex bradycardia then presynaptic effects lead to subsequent vasodilation
this alpha 2 agonist is a sedative used in healthy horses and ruminants and has side effects of AV block, reduced GI motility, sweating, increased myometrial tone
xylazine
this alpha 2 agonist is 50-100x more potent than xylazine and is used mostly in horses for standing surgery
detomidine
this alpha 2 agonist is used in SA sedation, dosed based in body surface area, makes over 50% of cats vomit. what is the drug? what is ir reversed with?
dexmedetomidine; reverse with atipamezole
this beta 1 agonist is a positive ionotrope that does not increase heart rate, is given as CRI, and can cause seizures in cats
dobutamine
this beta 2 agonist is a bronchodilator sometimes used to treat equine asthma, inhibits uterine tone, and is banned in food animals
clenbuterol
this non-selective adrenergic agonist is used for emergency treatment of anaphylaxis or for CPR; sometimes added to local anaesthetics to cause vasoconstriction, increases cardiac output and myocardial oxygen consumption
epinephrine
this alpha 1 antagonist reduces blood pressure, is used to treat functional urethral obstruction, and is 97% protein bound
prazosin
this alpha 2 antagonist acts as a competitive inhibitor to revise sedation, cardiovascular effects, and analgesia associated with alpha 2 agonist administration
atipamezole
