1.2 Autonomic Pharmacology Principles Flashcards
- largely autonomous, activities not under conscious control
- concerned primarily with visceral functions (cardiac output, blood flow, digestion)
- afferent (sensory) inputs
- output through reflex arcs of varying size and complexity
- anatomic divisions do not exclusively depend on transmitter release, or on effect evoked
autonomic nervous system
Sympathetic nervous system:
- thoracolumbar outputs
- preganglionic fibers terminate in _________
- postganglionic sympathetic fibers innervate _______
- ganglia (paravertebral chains)
- peripheral tissues
Adrenal medulla is a modified sympathetic ganglion, which receives sympathetic ________ fibers and releases epinephrine and norepi into the blood
preganglionic
Parasympathetic nervous system:
- craniosacral outputs
- preganglionic fibers terminate in _________
- postganglionic fibers originate in _____ and innervate organs
parasympathetic ganglia
ganglia
- walls of GI system, 3rd division of ANS
- myenteric plexus (Auerbach) and submucosal (Meissner) receives preganglionic PNS and postganglionic SNS inputs
enteric nervous system
- all preganglionic efferent autonomic fibers, somatic fibers to muscles, parasympathetic postganglionic fibers
- synthesized by ChAT, added to vesicles with VAT, release Calcium dependent, binds cholinoceptor, AchE on postsynaptic cells breaks it down, transporter takes choline back into presynaptic cell
acetylcholine (cholinergic)
- most postganglionic sympathetic fibers (a few release Ach)
- tyrosine to DOPA via tyrosine hydroxylase, DOPA to dopamine to norepi, put in vesicle by VMAT, interact with alpha and beta post synaptic receptors, not metabolized, diffuses away, uptake 1 transports into neurons
norepinephrine (adrenergic)
- analogous to postganglionic sympathetic neurons
- release a mix of epi and norepi
adrenal medullary cells
autonomic nerves releases co-transmitters (vasointestinal peptide, neuropeptide Y) which provide _________ activation of postsynaptic target tissue
long lasting
slowly developing
norepinephrine and epinephrine are metabolized by ______ in mitochondria of nerve terminal and _____ in postjunctional cell, but not primary mechanism for termination of action
monoamine oxidase (MAO)
catechol-o-methyl transferase (COMT)
cholinergic receptors respond to ________, muscarinic and nicotinic are subtypes
acetylcholine
adrenoceptors respond to ________, alpha and beta subtypes
catecholamines
- neither cholinergic nor adrenergic in action
- use peptides, nitric oxides, and purines
- important in GI and GU system function
nonadrenergic, noncholinergic neurons (NANC)
- major underlying tone at most end organs (NOT vasculature)
- slowing of the heart and stimulation of digestive activity
PNS
- fight or flight, recruited in times of stress
- cardiac stimulation, increased blood glucose, cutaneous vasoconstriction
SNS
- no innervation of peripheral vasculature by _____
- endothelial cells lining vasculature have ______ cholinoceptors
PNS
muscarinic
peripheral vasculature can be activated pharmacologically by ______, evokes production and release of _____ and vasodilation
acetylcholine
nitric oxide
______ is the main variable that is controlled by ANS actions, anything that alters it will stimulate compensatory reactions by the ANS, increasing peripheral resistance or tachy/bradycardia
mean arterial pressure
- pupillary dilator: iris, ______ receptors contract
- pupillary constrictor: iris, ______ receptors contract
- ciliary muscle: ______ receptors contract
adrenergic
muscarinic
muscarinic
_______ agonists:
- contract circular pupillary constrictor, miosis
- contract ciliary muscle for accomodation
- puts tension on trabecular meshwork, opens pores facilitating outflow of aqueous humor
muscarinic
contract radial pupillary dilator muscles –> mydriasis (open pupil)
alpha adrenoceptors
act on ciliary epithelium to secrete aqueous humor, blockade reduces secretion, useful in glaucoma
beta adrenoceptors
presynaptic autoreceptors usually ______ vesicular relase, include _____ receptors on postganglionic SNS neurons
inhibit
alpha 2
lack of activation of ________ receptor leads to denervation supersensitivity and upregulation of postsynaptic receptor number and/or affinity
postsynaptic
persistent activation of ________ receptor leads to desensitization or tachyphylaxis, down regulation of receptor number, internalization or phosphorylation of receptor proteins
postsynaptic receptors
acetylcholine is synthesized by?
choline acetyltransferase (ChAT)
acetylcholine binds to?
cholinoceptor
conversion of tyrosine to dopa by _________ is rate limiting
tyrosine hydroxylase
transports catecholamines into neuron and is inhibited by cocaine?
uptake 1
