Autonomics Flashcards
What are the two types of parasympathetic ANS receptors?
muscarinic (M) and nicotinic (N)
What are the agonists for muscarinic cholinoceptors?
Acetylcholine, Bethanechol, and Pilocarpine
What antagonist suppresses all parasympathetic signals to M and N receptors?
Atropine
What suppresses signals to muscarinic receptors?
Scopolamine
What tissues are innervated by M1 receptors?
Stomach (increase acid secretion)
What tissues are innervated by M2 receptors?
Heart
What effects do M2 receptors elicit on the heart?
- decrease HR via SA node
- decrease AP duration and contractility of atria
- decrease conduction velocity via AV node
- decrease contractility of ventricle
What tissues do M3 receptors innervate?
GI tract, secretory gland, eye, cardiac vessels, respiratory tract
What effects do M3 receptors elicit on the GI tract?
Contracts GI walls
What effects do M3 receptors elicit on the secretory glands?
Increase secretions
What effects do M3 receptors elicit on the eyes?
Constricts pupil via iris circular muscle
What do M3 receptors do for the heart?
Activation of EDRF release to vasodilate cardiac vessels
What effect do M3 receptors have on the respiratory tract?
Bronchoconstrict
What neurotransmitter do Nicotinic receptors use?
Acetylcholine
What do Nm receptors innervate?
They innervate muscle via neuromuscular junctions
What do Nn receptors innervate?
- autonomic ganglia in sympathetic chain and distance parasympathetic ganglia
- adrenal medulla (release of catecholamines)
What are the three biggest types of sympathetic ANS receptors?
alpha, beta, D (for dopamine-receptor)
What tissues do alpha1 receptors innervate?
Eye, GI sphincters, Genitourinary (GU) sphincters, and blood vessels
For all four tissues innervated by alpha1 receptors, will the agonist cause contraction or relaxation?
contraction (of iris radial muscle, of GI and GU sphincters, and of blood vessels)
What are the agonists for alpha1 receptors?
Epi > NE, and Phenylephrine (PE)
What is the antagonist that suppresses alpha1 action?
Prazosin
What tissues do alpha2 receptors innervate?
GI walls, NE terminals, brainstem, and blood vessels
What effect does an alpha2 agonist have on GI walls?
relaxation
What effect does an alpha2 agonist have on NE terminals and brainstem?
decrease NE release in both places
What do all alpha receptors do to blood vessels?
vasoconstriction
What are the alpha2 agonists?
Epi > NE, Clonidine, Guanfacine
beta1 receptors effect which organ?
Heart
How does a beta1 agonist effect the heart?
- raise HR via SA node
- increase contractility, automaticity
- increase conduction velocity of atria, AV node, His & Purkinje fibers, and Ventricles
What are the beta1 agonists?
Epi = NE, Isoproterenol
What antagonist suppresses all beta receptors?
Propranolol
What tissues do beta2 receptors innervate?
Eyes, heart, skeletal muscle vessels, trachea/bronchi, GI walls, bladder wall, uterus
An agonist does what to eyes via beta2 receptors?
Relaxes ciliary muscle
Epinephrine causes what to happen to the heart via beta2 receptors?
- raises HR via SA node
- increase contractility of heart
What effect do beta2 agonist have on skeletal muscle blood vessels, bronchi, GI walls, bladder wall, and uterus?
Relaxation of all
What are the beta2 agonists?
Epi, Isoproterenol, Albuterol, and Terbutaline
What beta blocker is used to treat anxiety and/or HTN by lowering blood pressure?
Propranolol
What beta2 agonist is a common bronchodilator used in asthma patients?
Albuterol
What beta receptor agonist is used to treat bradycardia?
Isoproterenol
What drug causes vasoconstriciton, sphincter contraction, and is used in decongestant medications?
Phenylephrine
What alpha1 antagonist is used to treat HTN?
Prazosin
What alpha2 agonist is used to regulate blood pressure?
Clonidine
How does d-Tubocurarine work?
It binds to Nm receptors to relax muscles
How does succinylcholine work?
It depletes the neuron of ions so that another action potential cannot signal for the muscle to contract.
What does bethanochol do?
it’s a muscarinic agonist that increases secretions and GI tract motility
How does pilocarpine work?
It binds to muscarinic receptors to increase secretions. In eye it causes the iris muscle to contract to increase fluid and drainage
What is an antimuscarinic drug used to treat motion sickness?
Scopolamine
What anticholinergic blocks ALL muscarinic and nicotinic receptors?
Atropine
