Medical Pharmacology: Autonomic Nervous System Pharmacology
 

Medical Pharmacology Chapter 4:  Autonomic (ANS) Pharmacology: Introduction

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ANS Neurotransmitters: Effector Organs

 

Eye

 

 

Adrenergic

Effects

 

Cholinergic

Iris: Radial Muscle

N.E., α-1 receptor

Contraction (mydriasis)

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Iris: Sphincter muscle

-----

-----

Contraction (miosis)

Ciliary Muscle

N.E., β2 receptor

Relaxation (far vision)

Contraction (near vision)

 

Heart

 

 

Adrenergic

Effects

 

Cholinergic

Sino-atrial (SA) Node

β1; β2

increase rate

Decrease rate (vagal)

Atrial muscle

β1, β2

Increased: contractility, conduction velocity

Decreased: contractility, action potential duration

Atrio-ventricular (AV) node

β1, β2

Increased: automaticity*, conduction velocity

Decreased conduction velocity; AV block

His-Purkinje System

β1, β2

Increased: automaticity, conduction velocity

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Ventricles

β1, β2

Increased: contractility, conduction velocity, automaticity, ectopic pacemaker

Small Decrease in contractility

*An increase in the slope of phase 4 depolarization results in enhanced automaticity.

 

The Capillary Bed

 

 

Arterioles

 

 

Effects

        Cholinergic

constriction

Coronary

α1,2; β2

Constriction;dilatation

Constriction

Skin/Mucosa

α 1, 2

Dilatation

Skeletal Muscle

α; β2

Constriction,dilatation

Dilatation

Cerebral

α1 

Slight Constriction

Dilatation

Pulmonary

α1, β2

Constriction; dilatation

Dilatation

Abdominal viscera

α1, β2

Constriction; dilatation

-------

Salivary glands

α1,2

constriction

Dilatation

Renal

α 1, 2; β,2

Constriction;dilatation

---------

 

Systemic Veins

 

Adrenergic Effects

Cholinergic

systemic veins

α1,2; β2

Constriction; dilatation

-----

 

Lung

 

 

Adrenergic Effects

Cholinergic

Tracheal and bronchial muscle

β2

Relaxation

Contraction

Bronchial glands

α1, β2

Decrease secretion; increased secretion

Stimulation

 

Kidney

 

Adrenergic Effects

Cholinergic

Renin Secretion

α1; β1

Decrease; increase

-------

 

Skin

 

 

Adrenergic Effects

Cholinergic

Pilomotor muscles

α1

Contraction

-----

Sweat glands

α1

localized secretion

generalized secretion

 

 

Adrenal Medulla

 

Adrenergic Effects

Cholinergic

Adrenal medulla

--

----

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

Adrenal Gland:  Physiology

 

 

 

 

Skeletal Muscle

 

 

Adrenergic Effects

Cholinergic

Skeletal Muscle

β2

Increased: contractility;
Glycogenolysis; potassium uptake

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Liver

 

 

Adrenergic Effects

Cholinergic

Liver

α1; β 2

Glycogenolysis and gluconeogenesis

--------

Adrenergic effects on the liver:  gluconeogenesis and the fight or flight response: epinephrine and G-protein mediation

 

 

Posterior Pituitary

 

 

Adrenergic Effects

Cholinergic

Posterior Pituitary

β 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