INTRODUCTION TO AUTONOMIC PHARMACOLOGY
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- anatomical characteristics of parasympathetic nerve fibers
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-originates craniosacral
nerve fibers are long preganglionic; short postganglionic
-Ganglia is located in tissue innervated - anatomical characteristics of sympathetic nerve fibers
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-originates thoracolumbar
nerve fibers are short preganglionic; long preganglionic
-ganglia is located in two paravertebral chains on either side of spinal column - anatomical characteristics of somatic nerve fibers
- only one neuron
- ALL autonomic preganglionic neurons are _______.
- cholinergic
- ALL parasympathetic postganglionic neurons are _______.
- cholinergic
- MOST sympathetic postganglionic neurons are _________.
- adrenergic
- The adrenal medulla is a modified _______.
- sypathetic ganglion
- “Effector†cells are (give 3)
- cardiac mm, smoothe mm, gland cells, and sometimes endothelial cells and nerve terminals
- Describe biosynthesis of Ach
- synthesized in cytoplasm from acetyl-CoA and choline through catalytic action of enzyme choline acetyltransferase (ChaT)
- storage of Ach
- Ach transported from cytoplasm into vesicles by antitransporter that removes protons. A "quanta" of Ach in each vesicle"
- release of Ach
- dependent on extra cellular Ca2+. When AP reaches terminal and triggers sufficient influx of Ca2+. Vesicles fuse with membrane and spit out Ach.
- metabolism of acetylcholine in the cholinergic junction.
- Acetyl cholinesterase (AChE) splits Ach into choline and acetate.
- biosynthesis of NE
- Tyrosine transported into the noradernegic ending by sodium dependent carrier. Tyrosine converted to dopamine which is transported into the vesicle by a carrier. Dopamine is converted to NE in the vesicle by dopamine B hydroxylase.
- release of NE
- action potential opens voltage-sensitive Ca2+ channels and increases intracellular Ca. Vesicles fuse w/ surfuse membrane and results in expulsion of NE.
- metabolism of NE
- NE diffuses out of cell or is transported into cytoplasm of terminal or postjunctional cell.
- parasympathetic presynaptic NT & receptor
- Ach;cholinoreceptor (Ach receptor)
- parasympathetic postsynaptic NT & receptor
- Ach;cholinoreceptor (Ach receptor)
- sypathetic presynaptic NT & receptor
- Ach;cholinoreceptor (Ach receptor)
- Sympathetic postsympathetic NT & receptor
- NE; Adrenoreceptors
- motor end plate NT & receptor
- Ach;cholinoreceptor (Ach receptor)
- role and location of (cholinocereptors) Muscarinic M1
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CNS
results in formation of IP3 & DAG, increased intracellular Ca - role and location of (cholinocereptors) Muscarinic M2
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MYOCARDIUM
FUNCTIONS IN OPENING OF POTASSIUM CHANNELS, INHIBITION OF ADENYL CYCLASE - role and location of (cholinocereptors) Muscarinic M3
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smooth muscles and glands
Formation of IP3 & DAG, increased intracellular calcium - role and location of (Adrenoceptors) alpha1 A1
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postsynaptic effector cells, especially smooth mm
Formation of IP3 & DAG, increased intracellular CA - role and location of (Adrenoceptors) alpha2 A2
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Presynaptic adrenergic nerve terminals (autoreceptors)
Inhibition of adenylyl cyclase, decreased cAMP - role and location of (Adrenoceptors) Beta1 B1
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heart
Stimulation of adenylyl cyclase, increased cAMP - role and location of (Adrenoceptors) Beta2 B2
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smooth mm
Stimulation of adenylyl cyclase, increased cAMP - role and location of (Adrenoceptors) Beta3 B3
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fat cells
Stimulation of adenylyl cyclase, increased cAMP -
Nicotinic NN
Typical location & result of ligand binding -
Postganglionic neurons, some presynaptic cholinergic terminals
Opening of Na+, K+ channels, depolarization - Nicotinic NM
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Skeletal muscles neuromuscular end plates
Opening of Na+, K+ channels, depolarization - D1 (DA1) & D5
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Brain & smooth muscles of renal vascular bed
Stimulation of adenylyl cyclase, increased cAMP - D2 (DA2)
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Brain & smooth muscles of renal vascular bed
Inhibition of adenylyl cyclase, decrease cAMP - Local anesthetics, tetrotoxin, saxitoxin
- blocks ACTION POTENTIAL PROPAGATION by acting on nerve axons to block sodium channels and thus block conduction.
- hemicholinium
- prevents TRANSMITTER SYNTHESIS by acting on CHOLINERGIC nerve terminals at the membrane to block the uptake of choline
- alpha-methyltyrosine (metyrosine)
- prevents TRANSMITTER SYNTHESIS by acting on ADRENERGIC nerve terminals and the adrenal medula at the cytoplasm to block NT synthesis
- Vesamicol
- prevents TRANSMITTER STORAGE by by acting of the vesicles in CHOLINERGIC TERMINALS
- Reserphine
- prevents TRANSMITTER STORAGE by by acting of the vesicles in ADERNERGIC TERMINALS
- Norepinephrine, dopamine, acetylcholine, angiotensin II, various prostaglandins
- Effects TRANSMITTER RELEASE by acting on nerve terminal membrane receptors to modulate release
- omega-Contoxin GVIA
- Reduces TRANSMITTER RELEASE by acting on nerve terminal calcium channels to reduce transmitter release
- BOTULINUM TOXIN
- Prevents TRANSMITTER RELEASE by acting on CHOLINERGIC vesicles to prevent release
- Alpha latrotoxin
- Effects TRANSMITTER RELEASE by acting on CHOLINERGIC and ADENERGIC vesicles causing an explosive release of NT
- Tyramine, amphetamine
- Promotes TRANSMITTER RELEASE by acting on ADRENERGIC nerve terminals to promote transmitter release
- Cocaine, Tricyclic antidepressants
- Inhibits TRANSMITTER UPTAKE AFTER RELEASE by acting on ADRENERGIC nerve terminals to inhibit uptake and increasing transmitter effect on postsynaptic receptors
- 6 Hydroxydopamine
- Effects TRANSMITTER UPTAKE AFTER RELEASE by destroying ADRENERGIC nerve terminals
- Norepenephrine
- Causes RECEPTOR ACTIVATION by acting on receptors at ADENERGIC junctions by binding to alpha receptors causing activation
- Phentolamine
- Causes RECEPTOR BLOCADE by acting on receptors at ADENERGIC junctions by binding to alpha receptors preventing activation
- Isoproterenol
- Causes RECEPTOR ACTIVATION by acting on receptors at ADENERGIC junctions by binding to beta receptors causing activation of adenylyl cyclase
- Propranolol
- Causes RECEPTOR BLOCADE by acting on receptors at ADENERGIC junctions by binding to beta receptors preventing activation
- Nicotine
- Causes RECEPTOR ACTIVATION by binding to receptors at nicotinic CHOLINERGIC junctions (autonomic ganglia, neuromuscular end plates) to bind nicotinic receptors opening ion channels in post synaptic membrane
- Tubocurarine
- Causes RECEPTOR BLOCKADE by acting on neuromuscular end plates to prevent activation
- Bethanechol
- Cuaes RECEPTOR ACTIVATION by acting receptors of parasympathetic effector cells (smooth mm, glands) to bind and activate muscarinic receptors
- Atropine
- Causes RECEPTOR BLOCKADE by acting receptors of parasympathetic effector cells (smooth mm, glands) to bind and inactivate muscarinic receptors
- Neostigmine
- Prevents ENZYMATIC INACTIVATION OF TRANSMITTER by acting on CHOLINERGIC synapses (acetylcholinesterase) to inhibit enzyme and prolong and intensify transmitter action
- Tranylcypromine
- Prevents ENZYMATIC INACTIVATION OF TRANSMITTER by acting on ADRENERGIC nerve terminals (monoamine oxidase) to inhibit enzyme; and increase stored transmitter pool
- Stimulation of Parasympathetic innervation of the CIRCULAR (sphincter)of the iris: effect & receptor
- contraction - miosis –M3
- block of stimulation of Parasympathetic innervation of the CIRCULAR (sphincter mm)of the iris: effect & receptor
- dilation – mydriasis -M3
- Stimulation of sympathetic innervation of the RADIAL smooth mm of the iris (dialator mm): effect & receptor
- dilation – mydriasis - alpha1
- Block of stimulation of sympathetic innervation of the RADIAL smooth mm of the iris (dialator mm): effect & receptor
- contraction - miosis –alpha1
- Stimulation of Parasympathetic innervation of the ciliary body (smooth mm): effect & receptor
- contracts – relaxes suspensory ligaments- allows lens to widen – focus for near vision (M3)
- Block stimulation of Parasympathetic innervation of the ciliary body (smooth mm): effect & receptor
- cycloplegia inabilidate to accomidate for near vision (M3)
- Stimulation of sympathetic innervation of the ciliary body (smooth mm): effect & receptor
- not under sympathetic control
- Function of canal of schlemm and results of blockage
- drainage of aqueous humor of the eye. If blocked, accumulation of AH results and increase intra ocular pressure. This can cause blindness.
- Parasympathetic and sympathetic considerations at the canal of schlemm
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Stimulation of cholenergic fibers will increase drainage
If you block Ach, you decrease drainage and glaucoma results.
Beta blockers interfere w/ production of aqueous humor and are bennifiial for glaucoma. - Stimulation of Parasympathetic innervation of the bladder : effect & receptor
- urinary retention -- M3
- Stimulation of sympathetic innervation of the bladder : effect & receptor
- relax detrusor mm(B2), constrict trigone mm (a1) causes urinary retention
- Block stimulation of sympathetic innervation of the bladder : effect & receptor
- not too much effect cuz parasymp predominates
- Stimulation of Parasympathetic innervation of the GI tract: effect & receptor
- increase GI motility and tone and relaxation of sphincters and increase in secretion of exocrine glands (m3)
- Blocked stimulation of Parasympathetic innervation of the GI tract: effect & receptor
- constipation (m3)
- Stimulation of sympathetic innervation of the GI tract: effect & receptor
- minimal effect – parasymp predominates
- Stimulation of sympathetic innervation of the heart: effect & receptor
- increae conduction at SA & AV node, & contraction of ventrical results in increae heart rate -- beta1
- Block stimulation of sympathetic innervation of the heart: effect & receptor
- decrease conduction and heart rate (e.g., beta blockers)
- Stimulation of parasympathetic innervation of the heart: effect & receptor
- L vagus nn-av node-receptor decrease HR (m2) , R vagus nn –sa node- decrease HR(m2)-, no fibers to ventricle.
- Stimulation of parasympathetic innervation of the blood vessels: effect & receptor
- No fibers to blood vessels but some M receptors present
- Block stimulation of parasympathetic innervation of the heart: effect & receptor
- increase HR increase conduction --M2
- _______ innervation predominates in the heart
- parasympathetic
- Stimulation of sympathetic innervation of the skin and visceral organ blood vessels: effect & receptor
- constriction of blood vessels -- alpha1
- Stimulation of sympathetic innervation of the skeletal mm blood vessels: effect & receptor
- relaxation of blood vessels -- beta2
- List the determinants of blood pressure
- ??
- and describe how the baroreceptor reflex mechanism functions when blood pressure rises or falls
- ??