Anesthesia Pharmacology Chapter 5:  Autonomic (ANS) Pharmacology: Introduction

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Autonomic Nervous System: Anatomical Considerations

Figure by Poul-Erik Paulev, M.D., D.Sci, used with permission

 

Autonomic and Somatic Innervation

 

Autonomic Reflex Arc

 

Autonomic Reflex Arc: First Link

Figure by Poul-Erik Paulev, M.D., D.Sci, used with permission

 

 

CNS and the Autonomic Nervous System

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Lefkowitz, R.J, Hoffman, B.B and Taylor, P. Neurotrasmission: The Autonomic and Somatic Motor Nervous Systems, In, Goodman and Gillman's The Pharmacologial Basis of Therapeutics,(Hardman, J.G, Limbird, L.E, Molinoff, P.B., Ruddon, R.W, and Gilman, A.G.,eds) TheMcGraw-Hill Companies, Inc.,1996, pp.107

Sympathetic Nervous System

 

Anatomical Outline

Lefkowitz, R.J, Hoffman, B.B and Taylor, P. Neurotrasmission: The Autonomic and Somatic Motor Nervous Systems, In, Goodman and Gillman's The Pharmacologial Basis of Therapeutics, (Hardman, J.G, Limbird, L.E, Molinoff, P.B., Ruddon, R.W, and Gilman, A.G.,eds) TheMcGraw-Hill Companies, Inc.,1996, pp.105-107.

 

Parasympathetic System: Cranial-Sacral Outflow

ANS Neurotransmitters: Effector Organs

Eye

 

 

Adrenergic

Effects

 

Cholinergic

Iris: Radial Muscle

N.E., alpha-1 receptor

contraction (mydriasis)

-----

Iris: Sphincter muscle

-----

-----

contraction (miosis)

Ciliary Muscle

N.E., beta2 receptor

relaxation (far vision)

contraction (near vision)

 

Heart

 

 

Adrenergic

Effects

 

Cholinergic

Sino-atrial (SA) Node

beta1; beta2

increase rate

decrease rate (vagal)

Atrial muscle

beta1, beta2

increased: contractility, conduction velocity

decreased: contractility, action potential duration

Atrio-ventricular (AV) node

beta1, beta2

increased: automaticity*, conduction velocity

decreased conduction velocity; AV block

His-Purkinje System

beta1, beta2

increased: automaticity, conduction velocity

------

Ventricles

beta1, beta2

increased: contractility, conduction velocity, automaticity, ectopic pacemaker

small decrease in contractility

Arterioles

 

Adrenergic

Effects

        Cholinergic

Coronary

alpha1,2; beta2

constriction;dilatation

constriction

Skin/Mucosa

alpha 1, 2

constriction

dilatation

Skeletal Muscle

alpha; beta2

constriction,dilatation

dilatation

Cerebral

alpha1 

slight constriction

dilatation

Pulmonary

alpha1, beta2

constriction; dilatation

dilatation

Abdominal viscera

alpha1, beta2

constriction; dilatation

-------

Salivary glands

alpha1,2

constriction

dilatation

Renal

alpha 1, 2;beta1,2

constriction;dilatation

---------

Systemic Veins

 

Adrenergic Effects

Cholinergic

systemic veins

alpha1,2; beta2

constriction; dilatation

-----

Lung

 

 

Adrenergic Effects

Cholinergic

Tracheal and bronchial muscle

beta2

Relaxation

contraction

Bronchial glands

alpha1, beta2

decrease secretion; increased secretion

stimulation

 

Kidney

 

Adrenergic Effects

Cholinergic

Renin Secretion

alpha1; beta1

decrease; increase

-------

Skin

 

 

Adrenergic Effects

Cholinergic

Pilomotor muscles

alpha1

contraction

-----

Sweat glands

alpha1

localized secretion

generalized secretion

Adrenal Medulla

 

Adrenergic Effects

Cholinergic

Adrenal medulla

--

----

Secretion of epinephrine and norepinephrine (mainly nicotinic and some muscarinic)

Skeletal Muscle

 

 

Adrenergic Effects

Cholinergic

Skeletal Muscle

beta2

increased: contractility;
glycogenolysis; potassium uptake

----------

 

Liver

 

 

Adrenergic Effects

Cholinergic

Liver

alpha1;beta 2

glycogenolysis and gluconeogenesis

--------

 

Posterior Pituitary

 

 

Adrenergic Effects

Cholinergic

Posterior Pituitary

beta 1

Antidiuretic hormone secretion (ADH)

------------

 

Based on Table 6-1: Lefkowitz, R.J, Hoffman, B.B and Taylor, P. Neurotransmission: The Autonomic and Somatic Motor Nervous Systems, In, Goodman and Gillman's The Pharmacologial Basis of Therapeutics, (Hardman, J.G, Limbird, L.E, Molinoff, P.B., Ruddon, R.W, and Gilman, A.G.,eds) TheMcGraw-Hill Companies, Inc.,1996, pp.110-111

Lefkowitz, R.J, Hoffman, B.B and Taylor, P. Neurotrasmission: The Autonomic and Somatic Motor Nervous Systems, In, Goodman and Gillman's The Pharmacologial Basis of Therapeutics, (Hardman, J.G, Limbird, L.E, Molinoff, P.B., Ruddon, R.W, and Gilman, A.G.,eds) TheMcGraw-Hill Companies, Inc.,1996, pp.108.

Neurotransmitters and the Autonomic Nervous System

Neurotransmission Steps

Cholinergic Neurotransmission

Cholinergic Transmission: Site Differences

Lefkowitz, R.J, Hoffman, B.B and Taylor, P. Neurotransmission: The Autonomic and Somatic Motor Nervous Systems, In, Goodman and Gillman's The Pharmacologial Basis of Therapeutics,(Hardman, J.G, Limbird, L.E, Molinoff, P.B., Ruddon, R.W, and Gilman, A.G.,eds) TheMcGraw-Hill Companies, Inc.,1996, pp.112-137

Catecholamine Synthetic Pathway

Adrenergic Neurotransmission: Introduction to the Neurotransmitters

Catecholamine Synthesis, Storage, and Release

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Shannon, M.T., Wilson, B.A., Stang, C. L. In, Govoni and Hayes 8th Edition: Drugs and Nursing Implications Appleton & Lange, 1995, pp. 616-619

Shannon, M.T., Wilson, B.A., Stang, C. L. In, Govoni and Hayes 8th Edition: Drugs and Nursing Implications Appleton & Lange, 1995, pp. 904-905

Lefkowitz, R.J, Hoffman, B.B and Taylor, P. Neurotransmission: The Autonomic and Somatic Motor Nervous Systems, In, Goodman and Gillman's The Pharmacologial Basis of Therapeutics,(Hardman, J.G, Limbird, L.E, Molinoff, P.B., Ruddon, R.W, and Gilman, A.G.,eds) TheMcGraw-Hill Companies, Inc.,1996, pp.112-137

 

-adrenergic receptors

 

Alpha Adrenergic Receptors

 

Other Autonomic Neurotransmitters/Cotransmitters

 

Predominant Sympathetic or Parasympathetic Tone

Antatomical Site

Predominant Autonomic Tone

Arterioles

Sympathetic-adrenergic

Veins

Sympathetic-adrenergic

Heart

Parasympathetic-cholinergic

Ciliary Muscle

Parasympathetic-cholinergic

Gastrointestinal Tract

Parasympathetic-cholinergic

Salivary Glands

Parasympathetic-cholinergic

Sweat Glands

Sympathetic-cholinergic

Taylor, P. Agents Acting at the Neuromuscular Junction and Autonomic Ganglia In, Goodman and Gillman's The Pharmacologial Basis of Therapeutics,(Hardman, J.G, Limbird, L.E, Molinoff, P.B., Ruddon, R.W, and Gilman, A.G.,eds) The McGraw-Hill Companies, Inc.,1996, pp.193-195. Adapted from Table 9-3

 

Baroreceptor Reflexes

  • A principal mechanism for arterial blood pressure control is the baroreceptor reflex.

  • The reflex is initiated by activation of stretch receptors located in the wall of most large arteries of the chest and neck.

  • A high density of baroreceptors is found in the wall of each internal carotid artery (just above the carotid bifurcation i.e. carotid sinus) and in the wall of the aortic arch.

 As pressure rises and especially for rapid increases in pressure:

  • baroreceptor input to the tractus solitarius of the medulla results in inhibition of the vasoconstrictor center and excitation of the vagal (cholinergic) centers resulting in:

  1. a vasodilatation of the veins and arterioles in the peripheral vascular beds.

  2. negative chronotropic and inotropic effects on the heart. (slower heart rate with reduced force of contraction)

 

 

Pharmacological Modification of Autonomic Function

Autonomic Dysfunction

 

 

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