- stimulates whole body response during physical and mental stressful situations.

-Adrenal medulla release epinephrine and some norepinephrine that travel to receptor sites and produce sympathetic responses (endocrine function).

1. Alpha 1: found on glands, smooth muscles, eyes, most arteries and veins 

• smooth muscle contraction and vasoconstriction which leads to increased BP 

• Dilation of pupils (mydriasis)

• Stimulated by NE and EPI (catecholamines)

2. Alpha 2 

• Relaxation/inhibition; parasympathetic response 

• Decreases contraction of smooth muscle and vasodilation which leads to lowered BP. 

• Negative feedback system. 

MOA: alpha 1 receptors are stimulated (adrenergic agonists)

• ephedrine increases BP, phenylephrine increased BP but is also a decongestant 

  
  

• increased blood pressure or itching

• directly stimulate/bind to the muscarinic receptors in the parasympathetic division 

• mimics ACH 

Drugs
1. acetylcholine-used for miosis, cataract and other eye surgeries. MOA: pupil constriction
2. pilocarpine (Pilocar®)-used for glaucoma. MOA: pupil constriction; decreases amount of fluid in eye; decreases intraocular pressure
3. bethanechol (Urecholine®)- used for urinary retention and ileus/intestinal stasis. MOA: stimulates muscarinic receptors of bladder and GI tract to prevent constipation and urinary retention post-op and in the elderly.

• located on cardiac, smooth muscle, and glands

• at parasympathetic postganglionic nerve endings  

• decrease HR, bronchoconstriction, ­ increase digestion, ­increase GI secretions, and increase urination, pupillary constriction

  
  

  nicotinic 1 (Nn): 

  • at ganglia of parasympathetic nerves and sympathetic nerves (synapse area) 

  nicotinic 2 (Nm): 

  • somatic, neuromuscular junction of skeletal muscle  

  • If stimulated, muscle contracts. (Somatic Nervous system-voluntary control; division of Peripheral Nervous System)

-stimulates only one body part or system.

• Located on the heart

• Stimulated by NE and EPI (stronger effect by EPI)

• Increase in force of contraction (inotropic)

• Increase in force of conduction (dromotropic)

• Increase in force of heart rate (chronotropic)

4. Beta 2 

• Located on smooth muscle, lungs, uterus, skeletal muscle arteries, and coronary arteries 

       - Smooth muscle 

       -Bronchodilation

      -Uterine relaxation

      -Relaxation of coronary arteries and skeletal muscle blood vessels (vasodilation)

      -stimulated by EPI only 

• NT released at ganglia from presynaptic nerve endings (both systems)

  
  

  
  

• NT released at postganglionic nerve endings

• synthesized from dopamine 

• released by adrenal medulla and neurons

• bind to cholinergic receptor 

• acts as a blocking drug; competitive antagonism 

Drugs

1. atropine- antidote for cholinergic poisoning; increase HR, decreases vagus nerve activity (parasympathetic), pre-op med-slows digestion and urination, mydriasis

2. dicyclomine(Bentyl®)-used for GI disorders (ulcers, colitis, IBS); decreases GI secretions and motility

3. ipratropium bromide (Atrovent®)-bronchodilation 

• epinephrine (Adrenalin®)

• prazosin (Minipress®)- HTN

• terazosin (Hytrin®)- HTN, BPH

• doxazosin (Cardura®)- HTN, BPH 

• terazosin (Hytrin®)

• Low dose stimulates d-1 receptors in kidneys causing vasodilation and increased renal blood flow. 

• Moderate dose stimulates beta 1 receptors-heart, increases force of contraction and cardia output

• High dose stimulates alpha 1 receptors causing vasoconstriction that increase in blood pressure

Dobutamine is used treatment of shock, increases blood pressure, and increases heart function.

• Stimulates beta 2 receptors 

• Relaxation of the smooth muscle of the lungs (bronchodilation)

• Relaxation of the smooth muscle of the uterus 

Drugs

1. albuterol (Proventil®, Ventolin®)- bronchodilator

2. terbutaline (Brethine®)- bronchodilator, uterine relaxant

3. formoterol (Foradil®)- bronchodilator

Used for asthma, respiratory illness, disease, preterm labor

4. salmeterol (Serevent®)- bronchodilator

• beta-1 receptor is blocked (antagonizes beta-1 effects of NE and EPI)

• decreases force of contraction (negative inotropic), decreases cardiac output

• decreases HR (negative chronotropic)

• decreases conduction (negative dromotropic) 

• decrease in cardiac output also decreases BP 

Drugs

1. atenolol (Tenormin®)

2. metoprolol (Lopressor®)

Used for hypertension (HTN), angina, arrhythmias, tachycardia, migraines, glaucoma (lowers IOP), heart failure (decreases sympathetic activity)

• block beta-1 and beta-2 receptors

• decreases force of contraction (negative inotropic), decreases cardiac output

• decreases HR (negative chronotropic)

• decreases conduction (negative dromotropic)

• decrease in cardiac output also decreases BP

• can cause bronchoconstriction 

Drugs

1. nadolol (Corgard®)

2. propanolol (Inderal®)

3. timolol (Blocadren®) 

Used for HTN, arrhythmias, angina, tachycardia, migraines, glaucoma (lower IOP), heart failure (decreases sympathetic activity)

Contraindication: asthma and respirator disease patient, can trigger respiratory distress 

• increased urinary frequency and diarrhea

• chest pain or swelling

• dry mouth or blurred vision

• changes in heart rate or blood pressure

• low blood pressure or dizziness

• nausea or headaches

• Dizziness or chest pain

• diarrhea or stomach pain

• constipation or body aches

• inhibit acetylcholinesterase, the enzyme that destroys ACH in the synapse and increases ACH 

Drugs
1. neostigmine (Prostigmin®)

Used for urinary retention and intestinal stasis/ ileus, reversal of anticholinergic-rocuronium bromid (Zemuron®) with respiratory paralysis from anesthesia by increasing ACH at the nicotinic 2 (Nm) receptors on skeletal muscle, treatment for myasthenia gravis