Autonomic Pharmacology: Introduction

 

Chapter 4:  Autonomic (ANS) Pharmacology: Introduction

Table of Contents

 

Autonomic Nervous System: Anatomical Considerations

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

Autonomic and Somatic Innervation

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Autonomic Reflex Arc

 

Autonomic Reflex Arc: First Link

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

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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

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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

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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) ------------

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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

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Alpha Adrenergic Receptors

 

Other Autonomic Neurotransmitters/Cotransmitters

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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

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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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