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100 Cards in this Set
- Front
- Back
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Sympathetic Innervation
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*Neurons arise in thoracic, lumbar regions
*Short preganglionic neurons, long post |
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Parasympathetic Innervation
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*Neurons arise in cranial, sacral regions
*Long preganglionic neurons, short post |
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Neurotransmitters in PNS
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*Acetylecholine
-sympathetic and parasympathetic preganglionic neurons -somatic motor neurons -parasympathetic postganglionic neurons -sympathetic postganglionic neurons that innervate sweat glands *Norepinephrine -all other sympathetic postganglionic neurons |
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Receptors in PNS
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*Nicotinic ACh receptors (stimulated by ACh)
-Parasympathetic post-ganglionic neurons -Sympathetic post-ganglionic neurons -Neuromuscular junctions -Muscarinic receptors (sweat glands - stimulated by ACh and Tissues innervated by parasympathetic postganglionic nuerons - stimulated by ACh) -Adrenergic receptors (stimulated by Norepinephrine) alpha and beta receptors on tissues (except sweat glands) innervated by the sympathetic postganglionic neurons |
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Catecholamines
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*Dopamine
*Norepinephrine *Epinephrine *MAOIs -Tyramine is metabolized by MAO -Tyramine displaces NE from vesicles -Tyramine + MAOIs can lead to hypertensive crisis |
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Classification of Sympathomimetic Drugs
Nonselective adrenoreceptor agonists |
Nonselective adrenoreceptor agonists
*Norepinephrine *Epinephrine *Dobutamine |
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Classification of Sympathomimetic Drugs
Alpha-Selective Adrenoreceptor agonists |
*Nonselective alpha-agonists
-oxymetazoline (afrin), tetrahydrozoline -clinically:agents are used topically in which case alpha-1 is predominant *Alpha1-selective agonists (phenylephrine, pseudoephedrine) *Alpha2-selective agonists (clonidine, guanabenz, guanfacine, alpah-methyldopa) |
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Selectivity of Adrenoreceptor Agonists
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*Alpha Agonists
-Phenylephrine (a1>a2>>>>B) -Clonidine (a2>a1>>>>>B) *Mixed a and B agonists -Norepinephrine a1=a2; B1>>B2 -Epinephrine a1=a2; B1=B2 |
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Alpha1 effect on:
Most vascular smooth muscle (Innervated) Functional Effects of Sympathomimetic Drugs |
Alpha1 effect on:
Most vascular smooth muscle (Innervated) CONTRACTION |
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Alpha1 effect on:
Pupillary dilator muscle Functional Effects of Sympathomimetic Drugs |
Alpha1 effect on:
Pupillary dilator muscle CONTRACTION (dilates pupils) |
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Alpha1 effect on:
Pilomotor smooth muscle Functional Effects of Sympathomimetic Drugs |
Alpha1 effect on:
Pilomotor smooth muscle ERECTS HAIR |
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Alpha1 effect on:
Prostate Functional Effects of Sympathomimetic Drugs |
Alpha1 effect on:
Prostate CONTRACTION |
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Alpha1 effect on:
Heart Functional Effects of Sympathomimetic Drugs |
Alpha1 effect on:
Heart INCREASE FORCE OF CONTRACTION |
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Alpha2 effect on:
Platelets Functional Effects of Sympathomimetic Drugs |
Alpha2 effect on:
Platelets AGGREGATION |
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Alpha2 effect on:
Adrenergic nerve terminals Functional Effects of Sympathomimetic Drugs |
Alpha2 effect on:
Adrenergic nerve terminals INHIBITS TRANSMITTER RELEASE |
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Alpha2 effect on:
Some vascular smooth muscle Functional Effects of Sympathomimetic Drugs |
Alpha2 effect on:
Some vascular smooth muscle CONTRACTION |
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Alpha2 effect on:
Fat cells Functional Effects of Sympathomimetic Drugs |
Alpha2 effect on:
Fat cells INHIBITS LIPOLYSIS |
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Beta1 effect on:
Heart Functional Effects of Sympathomimetic Drugs |
Beta1 effect on:
Heart INCREASE FORCE AND RATE OF CONTRACTION |
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Beta2 effect on:
Respiratory, uterine, vascular smooth muscle Functional Effects of Sympathomimetic Drugs |
Beta2 effect on:
Respiratory, uterine, vascular smooth muscle PROMOTES SMOOTH MUSCLE RELAXATION |
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Beta2 effect on:
Skeletal Muscle Functional Effects of Sympathomimetic Drugs |
Beta2 effect on:
Skeletal Muscle PROMOTES POTASSIUM UPTAKE |
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Beta2 effect on:
Liver Functional Effects of Sympathomimetic Drugs |
Beta2 effect on:
Liver ACTIVATES GLYCOGENOLYSIS |
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Beta3 effect on:
Fat Cells Functional Effects of Sympathomimetic Drugs |
Beta3 effect on:
Fat Cells ACTIVATES LIPOLYSIS |
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D1 effect on:
Smooth muscle Functional Effects of Sympathomimetic Drugs |
D1 effect on:
Smooth muscle DILATES RENAL BLOOD VESSELS |
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D2 effect on:
Nerve endings Functional Effects of Sympathomimetic Drugs |
D2 effect on:
Nerve endings MODULATES TRANSMITTER RELEASE |
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Classification of Sympathomimetic Drugs
B-selective adrenoreceptor agonists |
Nonselective B-agonist - Isoproterenol (not used)
B1-selective agonists - Xamoterol (not used) B2-selective agonists - Metaproterenol, terbutaline, albuterol, salmeterol, formoterol, pirbuterol, bitolterol |
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Selectivity of adrenoreceptor agonists
B-agonists |
B-agonists
*Dobutamine B1>B2>>>>>a *Isoproterenol B1=B2>>>>a *Terbutaline/albuterol B2>>B1>>>>>a |
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Selectivity of adrenreceptor agonists
Dopamine agonists |
Dopamine agonists
*Dopamine D1=D2>>B>>a *Fenoldopam D1>>D2 |
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Cardiovascular Effects of
Adrenoreceptors a1 |
Major role of adrenoreceptors - BP regulation
*a1 - vasoconstriction - increases BP |
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Cardiovascular Effects of
Adrenoreceptors a2 |
Major role of adrenoreceptors - BP regulation
*a2 - negative feedback - decreases BP |
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Cardiovascular Effects of
Adrenoreceptors B1 |
Major role of adrenoreceptors - BP regulation
*B1 - increased CO - increases BP |
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Cardiovascular Effects of
Adrenoreceptors B2 |
Major role of adrenoreceptors - BP regulation
*B2 - peripheral vasodilation - decreases BP |
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Ocular Effects of
Adrenoreceptors a1 |
*Accommodation for far vision
- a1 - mydriasis |
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Ocular Effects of
Adrenoreceptors a1 & a2 |
*Regulation of intraocular pressure
-a1, a2 - increase humoral outflow |
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Ocular Effects of
Adrenoreceptors B1 |
*Regulation of intraocular pressure
-B1 - increase production of aqueous humor |
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Respiratory Effects of
Adrenoreceptors B2 |
*Dilate bronchioles - B2
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Respiratory Effects of
Adrenoreceptors a1 |
*Reduce mucosal secretion - decongestion
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GI Effects on
Adrenoreceptors a2, B2 |
*decreased peristalsis
-a2, B2 - direct smooth muscle relaxation |
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GI Effects on
Adrenoreceptors a2 |
*Decreased digestive secretions - a2
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GI Effects on
Adrenoreceptors a1 |
*Bladder - contraction of urethral sphincter - urinary continence - a1
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GI Effects on
Adrenoreceptors B2 |
*Bladder - relaxation - decreases urinary output - B2
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GI Effects on
Adrenoreceptors a1 |
*Erectile Tissue - a1 - facilitates ejaculation
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GI Effects on
Adrenoreceptors B2 |
*Uterus - B2 - relaxation - inhibits labor
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Direct-acting Sympathomimetics: Catecholamines
Epinephrine - a1 |
a1 - vasoconstriction
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Direct-acting Sympathomimetics: Catecholamines
Epinephrine - B1 |
B1 - cardiac stimulation
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Direct-acting Sympathomimetics: Catecholamines
Epinephrine - B2 |
B2 - vasodilation
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Direct-acting Sympathomimetics: Catecholamines
Norepinephrine - a1 |
a1 - vasoconstriction
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Direct-acting Sympathomimetics: Catecholamines
Norepinephrine - B1 |
B1 - cardiac stimulation
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Direct-acting Sympathomimetics: Catecholamines
Isoproterenol |
B1 - cardiac stimulation
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Direct-acting Sympathomimetics: Catecholamines
Dopamine (dose dependent) - D1/D2 |
D1/D2 - renal vasodilation
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Direct-acting Sympathomimetics: Catecholamines
Dopamine (dose dependent) - B1 |
B1 - cardiac stimulation
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Direct-acting Sympathomimetics: Catecholamines
Dopamine (dose dependent) - a1 |
a1 vasoconstriction
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Direct-acting Sympathomimetics: Non-Catecholamines
a1-agonists |
*Not inactivated by COMT
-longer duration of action -better access into brain *a1-agonists -Phenylephrine - mydriatic, decongestant, pressor -Methoxamine - increases BP -Midodrine (ProAmatine) - postural hypotension -Oxymetazoline tetrahydrozoline, xylometazoline - nasal and ocular decongestants |
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Direct-acting Sympathomimetics: Non-Catecholamines
a2-agonist |
*Not inactivated by COMT
-longer duration of action -better access into brain *a2-agonists -Clonidine - CNS receptors - decreases BP -Apraclonidine - ciliary receptors - reduces intraocular pressure |
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Direct-acting Sympathomimetics: Non-Catecholamines
B2-agonists |
*Not inactivated by COMT
-longer duration of action -better access into brain *B2-agonists -Albuterol, terbutaline, pirbuterol, botolterol, metaproterenol - asthma, COPD -Salmeterol, formoterol - long duration of action -Ritodrine - relax uterus - delay premature labor |
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Indirect-acting Sympathomimetics
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*Enhance release of catecholamines
*Amphetamine - increases release of norepinephrine and dopamine *Methamphetamine - similar to amphetamine but higher CNS effects *Methylphenidate (Ritalin, pemoline (Cylert) - amphetamine variants - ADHD |
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Selectivity of Adrenoreceptor Antagonists
a-antagonists |
*Prazosin, terazosin, doxazosin - a1>>>>>a2
*Phentolamine - a2=a1 *Yohimbine, tolazoline - a2>>a1 |
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Selectivity of Adrenoreceptor Antagonists
mixed a- and B-antagonists |
*Labetalol, carvedilol - B1=B2>a1>a2
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Selectivity of Adrenoreceptor Antagonists
B-antagonists |
*Metoprolol, atenolol, esmolol - B1>>>B2
*Propanolol, nadolol, timolol - B1=B2 *Butoxamine - B2>>>B1 |
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a-Antagonists
General Info |
*a-receptor responds faster than B-receptor
*Blocks stimulatory effects of norepinephrine on a-receptor -reversible (phentolamine) -irreversible (phenoxybenzamine) |
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a-Antagonists
Effects |
*Cardiovascular effects
-a1 antagonism decreases PVR and lowers BP, postural hypotension due to failure of venous vasoconstriction upon standing. -a2 antagonism - increases norepinephrine release from nerve terminals *GU effects - blockade in prostate and bladder cause muscle relaxation and ease micturation *Miosis *Increased nasal stuffiness |
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a-Antagonist
Drugs |
*Phentolamine, phenoxybenzamine (vasodilation - lowers BP)
*Prazosin (Minipress), terazosin (Hytrin), doxazosin (Cardura), tamsulosin (Flomax) - HTN, BPH *Yohimbine - diabetic neuropathy, enhance male sexual function, reverse effects of clonidine withdrawal |
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B-Antagonists
General Info |
Antagonist winds
-propanolol (vasodilation) wins over epinephrine (vasoconstriction) |
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B-Antagonists
Effects |
*Cardiovascular effect
- Decreases CO, BP - Increases Na+ retention *Respiratory effects -increases airway resistance *Ocular effects *Decreases aqueous humor production *Metabolic effects -decreases carbohydrate metabolism, which decreases insulin release -decreases renin secretion, which decreases angiotensin II -decreases sodium excretion -decreases lipolysis |
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B-Antagonists
Drugs |
*Timolol - topical ocular hypotensive agents
*Betaxolol - glaucoma *Most others used as CV agents |
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Acetylcholine Synthesis and Release
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*Botulinum toxin
- prevents exocytosis of presynaptic vessicles - prevents release of ACh at Nm receptors |
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Cholinergic Receptor Subtypes
M1 |
M1
Autonomic ganglia, CNS |
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Cholinergic Receptor Subtypes
M2 |
M2
Cardiac muscle |
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Cholinergic Receptor Subtypes
M3 |
M3
smooth muscle, glandular tissues |
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Cholinergic Receptor Subtypes
M4 & M5 |
M4 & M5
CNS |
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Cholinergic Receptor Subtypes
Nm |
Nm
skeletal muscle at NMJ |
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Cholinergic Receptor Subtypes
Nn |
Nn
autonomic ganglia, adrenal medulla, CNS |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Vasculature (endothelial cells) |
Vasculature (endothelial cells)
Release of NO and vasodilation |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Eye Iris (pupillae sphincter muscle) |
Eye Iris (pupillae sphincter muscle)
Contraction and miosis |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Ciliary Muscles |
Ciliary Muscles
Thin and watery secretions |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Salivary and lacrimal glands |
Salivary and lacrimal glands
Release of NO and vasodilation |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Bronchi |
Bronchi
Constriction; increase secretions |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Heart |
Heart
Bradycardia, decrease conduction velocity, AV block at high doses, slight decrease in contractility |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
GI Tract |
GI Tract
Increase tone, secretions; relaxation of sphincters |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Urinary Bladder |
Urinary Bladder
Contraction of detrusor muscle; relaxation of sphincter |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Sweat Glands |
Sweat Glands
Diaphoresis |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Reproductive tract, male |
Reproductive tract, male
Erection |
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Effects of Acetylcholine on Muscarinic Receptors in Peripheral Tissues
Uterus |
Uterus
Variable |
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Effects of Ganglionic Blockade on Tissues
Arterioles |
Arterioles
Predominant Tone: Sympathetic (adrenergic) Effects of Ganglionic blockade: Vasodilation; increased peripheral blood flow; hypotension |
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Effects of Ganglionic Blockade on Tissues
Veins |
Veins
Predominant Tone: Sympathetic (adrenergic) Effects of Ganglionic blockade: Vasodilation; pooling of blood; decrease venous return; decrease cardiac output |
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Effects of Ganglionic Blockade on Tissues
Heart |
Heart
Predominant Tone: Parasympathetic (cholinergic) Effects of Ganglionic blockade: tachycardia |
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Effects of Ganglionic Blockade on Tissues
Iris |
Iris
Predominant Tone: Parasympathetic (cholinergic) Effects of Ganglionic blockade: Mydriasis (pupil dilation) |
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Effects of Ganglionic Blockade on Tissues
Ciliary Muscle |
Ciliary Muscle
Predominant Tone: Parasympathetic (cholinergic) Effects of Ganglionic blockade: Cycloplegia (focused to far vision) |
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Effects of Ganglionic Blockade on Tissues
GI Tract |
GI Tract
Predominant Tone: Parasympathetic (cholinergic) Effects of Ganglionic blockade: decrease tone and motility; constipation; decrease secretions |
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Effects of Ganglionic Blockade on Tissues
Urinary Bladder |
Urinary Bladder
Predominant Tone: Parasympathetic (cholinergic) Effects of Ganglionic blockade: Urinary retention |
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Effects of Ganglionic Blockade on Tissues
Salivary Glands |
Salivary Glands
Predominant Tone: Parasympathetic (cholinergic) Effects of Ganglionic blockade: Xerostomia (dry mouth) |
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Effects of Ganglionic Blockade on Tissues
Sweat Glands |
Sweat Glands
Predominant Tone: Sympathetic (cholinergic) Effects of Ganglionic blockade: An |
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AChE Inhibitors
Mechanisms |
*Elevates concentration of endogenously released ACh in synapse
*Increases transmission at Nm junction *Increases parasympathetic tone *Increases central cholinergic activity |
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AChE Inhibitors
Benefits |
*Useful in diseases of the Nm junction
-Myasthenia gravis - pyridostigmine, neostigmine *Glaucoma -Increases outflow of aqueous humor - physostigmine (Isopto) *Abdominal distension - increases smooth muscle motility - neostigmine *AD and other forms of cognitive dysfunction - Tacrine (Cognex), donepezil (Aricept), rivastigmine (Exelon), galantamine (Razadyne) |
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AChE Inhibitors
AE/CI |
AE:
*Peripheral ACh effects of GI tract *N/V/D, anorexia, flatulence, abdominal cramping *Dose-dependent CI: *Unstable or severe cardiac disease *Uncontrolled epilepsy *Active PUD |
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Receptor Agonists
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*Selectivity of muscarinic or nicotinic receptors
*Cross-reactivity with virtually all agents *ACh not administered due to broad activity and rapid hydrolysis by AChE |
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Muscarinic Agonists
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*Diagnosis of asthma (Methacholine)
*Miosis and decreased intraocular pressure (Carbachol) *GI and urinary tract motility - post-op and post-partum urinary retention, neurogenic bladder (Bethanechol) |
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Nicotinic Agonists
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Syccinylcholine
*Resistant to AChE *Induction of paralysis by means of depolarizing blockade *Continuous activation of nicotinic receptor channels results in neuronal depolarization blockade |
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Muscarinic Antagonists
Drugs |
*Allow sympathetic responses to predominate
*Atropine -Mydriasis for opthalmologic exams -Reverses symptomatic sinus bradycardia -Inhibits excessive salivation and mucus secretion during surgery -Prevents vagal reflexes induced by surgical trauma of visceral organs *Scopolamine - motion sickness (transdermal patch) *Ipratropium (Atrovent), tiotropium (Spiriva)- COPD - Bronchodilator *Oxybutynin (Ditropan), tolterodine (Detrol) - overactive bladders - nonspecific M-rc *Darifenacin (Enablex), solifenacin (vesicare) - overactive bladder - M3 specific |
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Muscarinic Antagonists
AE/CI |
AE:
blurred vision, dry mouth, ileus, urinary retention, flushing, agitation, tachycardia CI: in angle-closure glaucoma *Use with caution in elderly |
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Nicotinic Antagonists
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*Prevent endogenous ACh binding to nicotinic receptors and subsequent muscle cell depolarization
*Paralysis *Pancuronium, vecuronium, rocuronium |
