Pharmacology of the ANS Flashcards
What is the orgin of the fibres in the sympathetic ANS?
-
Preganglionic
- Thoracolumbar
-
Postganglionic
- Paravertebral chain
- Prevertebral ganglia
What is the origin of fibres in the parasympathetic ANS?
-
Preganglionic
- Craniosacral
-
Postganglionic
- In or near target organ
What is the purpose of autonomic reflex arcs?
Visceral control. The path of afferent fibres can explain referred pain.
What are the effects on the heart of sympathetic and parasympathetic innervation?
-
Parasympathetic
- Decreased heart rate
-
Sympathetic
- Increased heart rate
- Increased force of contraction
What are the effects on the digestive tract of sympathetic and parasympathetic innervation?
-
Parasympathetic
- Increased motility and secretion
-
Sympathetic
- Decreased motility and secretion
What are the effects on the lungs of sympathetic and parasympathetic innervation?
-
Parasympathetic
- Bronchoconstriction
-
Sympathetic
- Bronchodilation
What are the effects on the urinary bladder of sympathetic and parasympathetic innervation?
-
Parasympathetic
- Release of urine
-
Sympathetic
- Urinary retention
What are the effects on the pupil of the eye of sympathetic and parasympathetic innervation?
-
Parasympathetic
- Constricts
-
Sympathetic
- Dilates
What are the effects on the male sexual organs of sympathetic and parasympathetic innervation?
-
Parasympathetic
- Erection
-
Sympathetic
- Ejaculation
What are the effects on the blood vessels of sympathetic and parasympathetic innervation?
-
Parasympathetic
- No effect (mostly)
-
Sympathetic
- Constriction (mostly)
What are the effects on the salivary glands of sympathetic and parasympathetic innervation?
-
Parasympathetic
- Increased secretion
-
Sympathetic
- Increased secretion
What are the effects on the sweat glands of sympathetic and parasympathetic innervation?
-
Parasympathetic
- No effect
-
Sympathetic
- Increased secretion
What are the effects on the liver of sympathetic and parasympathetic innervation?
-
Parasympathetic
- No effect
-
Sympathetic
- Glycogenolysis
- Gluconeogenesis
Describe the role of the ANS in the eye.
-
Pupillary dilator muscle
- Sympathetic innercation only - mydriasis
-
Pupillary constrictor muscle
- Parasympathetic innervation - miosis
NB - when there is a blockage in the canal of Schlemm, could either use an agonist of the parasympathetic NS or an antagonist of the sympathetic NS.
Describe the role of the ANS in the urinary bladder.
- When the bladder is filling:
-
Sympathetic control predominates
- Relaxation of detrusor muscle
- Contraction of internal sphincter muscle
-
Sympathetic control predominates
- When the bladder is full:
-
Parasympathetic control predominates
- Contraction of detrusor muscle
- Relaxation of internal sphincter muscle
-
Parasympathetic control predominates
Which neurotransmitter is released by all preganglionic neurons in the parasympathetic and sympathetic systems?
Which receptors does it affect?
Acetylcholine
Acts on nicotinic receptors
Which neurotransmitter is released by all postganglionic parasympathetic neurons?
Which receptors does it affect?
Acetylcholine
Acts on muscarinic receptors
Which neurotransmitter is released by most postganglionic sympathetic neurons?
Noradrenaline
Some release ACh (i.e. sweat glands)
List the predominate locations of nicotinic ACh receptors.
- Neuromuscular junction
- Sympathetic ganglia
- Parasympathetic ganglia
- Central nervous system
List the predominate locations of muscarinic ACh receptors.
- Parasympathetic target organs
- Sweat glands (sympathetic)
- Vascular smooth muscle
- Central nervous system
What are the main locations of M1 (neural) muscarinic receptors?
- Autonomic ganglia
- Glands
- Gastric
- Salivary
- Lacrimal
What is the main location of M2 (cardiac) muscarinic receptors?
Heart: atria
What are the main locations of M3 (glandular / smooth muscle) muscarinic receptors?
- Exocrine glands
- Gastric
- Salivary
- Smooth muscle
- GI tract
- Eye
- Airways
- Bladder
- Blood vessels
- Endothelium
What are the cellular and functional responses of the M1 muscarinic receptors?
-
Cellular response
- Increased IP3
- DAG
-
Functional response
- Gastric secretion
What are the cellular and functional responses of the M2 muscarinic receptors?
-
Cellular response
- Decreased cAMP
-
Functional response
- Decreased heart rate
What are the cellular and functional responses of the M3 muscarinic receptors?
-
Cellular response
- Increased IP3
- DAG
-
Functional response
- Gastric secretion
- Salivary secretion
- GI smooth muscle contraction
- Ocular accommodation
- Vasodilation
Give 2 examples of muscarinic ACh receptor agonists.
- Pilocarpine
- Bethanechol
What are the pharmalogical properties of pilocarpine?
Non-selective muscarinic agonist