# data[].attributes.body
Acetylcholine (ACH) stimulates the cholinergic receptor.

# data[].attributes.body
ACH is released at the ganglia.

# data[].attributes.headline
Receptors Associated, Their Locations, and Their End Organ Responses

# data[].attributes.subject
Receptors Associated, Their Locations, and Their End Organ Responses

# data[].attributes.body
There are two main types of receptors in the parasympathetic division. The umbrella term for both receptors is "cholinergic" - the two main types of cholinergic receptors are known as "muscarinic" and "nicotinic" receptors.

These two receptors serve the same function but were given different names based on their differing cholinergic sites.

Muscarinic receptors are found on the cell membranes of visceral organs and glands. They are stimulated by ACH released by postganglionic nerve endings. The reaction caused by the stimulation isn't set in stone - it varies based on the individual organ receiving the stimulation. Some organ actions are increased (such as the GI tract), while others are decreased (such as the heart).

There are two types of nicotinic receptors: Nicotinic-Nerve (NN) and Nicotinic-Muscle (NM). NN receptors are located at ganglia and are stimulated by ACH released by preganglionic nerve endings. NM receptors are located on cell membranes of skeletal muscle and are stimulated by ACH released by somatic nerve endings. NN receptors conduct impulses across the autonomic ganglia to both of the postganglionic fibers across both ANS divisions, while NM receptors contract skeletal muscle.

# data[].attributes.body
Direct-Acting Cholinergic Drugs
- Stimulates the muscarinic receptors by mimicking ACH
- Main effects include decreased ocular pressure, constriction of the pupil, and a decrease in the amount of ocular fluid
- Drug example is bethanechol (Urecholine®)

Indirect-Acting Cholinergic Drugs (Anticholinesterases)
- Increases the amount of ACH at Nicotinic-Muscular receptors
- Main effects include urinary retention and the reversal of anticholinergic
- Drug example is neostigmine (Prostigmin®)

Parasympatholytic/Anticholinergic Drugs
- Decrease activity of the parasympathetic division
- Main effects include heart rate increase and the opening up of airways.
- Drug example is dicyclomine (Bentyl®)

# data[].attributes.body
Norepinephrine (NE) stimulates the adrenergic receptor.

# data[].attributes.body
NE is released at the postganglionic nerve endings.

# data[].attributes.headline
Receptors Associated, Their Locations, and Their End Organ Responses

# data[].attributes.subject
Receptors Associated, Their Locations, and Their End Organ Responses

# data[].attributes.body
The term for the sympathetic receptors is "adrenergic receptors." There are two subsets of receptors for the sympathetic division: Alpha and Beta receptors. Those receptors are further subdivided into Alpha-1, Alpha-2, Beta-1, and Beta-2.

Alpha-1 receptors are located on smooth muscle membranes of arteries, veins, and sphincters of the urinary and gastrointestinal tract. When stimulated, they produce a contraction.

Alpha-2 receptors are located on adrenergic nerve endings. When stimulated, they produce a negative feedback mechanism for any additional releases of NE.

Beta-1 receptors are located on the cardiac muscle. When stimulated, they produce a contraction and increase heart rate.

Beta-2 receptors are located on the smooth muscle of coronary arteries, skeletal muscle blood vessels, and bronchiolar smooth vessels. When stimulated, they produce vasodilation (blood vessel dilation) and bronchodilation (bronchiolar smooth muscle relaxation), which increases blood flow to skeletal muscle and heart, and delivers more oxygen to the lungs.

# data[].attributes.body
Alpha-1 Adrenergic Agonists:
- Receptor site is the Alpha-1 receptors
- Main drug effects include contraction of Alpha-1 mediated smooth muscle (vasoconstriction) and increased blood pressure
- Drug example is phenylephrine (Neo-Synephrine®)

Alpha-1 Adrenergic Antagonists:
- Receptor site is the Alpha-1 receptors
- Main drug effects include the relaxation of Alpha-1-mediated smooth muscle (vasodilation) and decreased blood pressure
- Drug example is prazosin (Minipress®)

Alpha-2 Adrenergic Agonists:
- Receptor site is the Alpha-2 receptors
- Main drug effect is a negative feedback effect to decrease the release of NE
- Drug example is epinephrine (Adrenalin®)

Beta-1 Adregenic Agonists:
- Receptor site is the Beta-1 receptors
- Main drug effects include cardiac stimulation, increased heart rate, and increased force of contraction
- Drug example is dobutamine (Dobutrex®)

Beta-1 Adregenic Antagonists:
- Receptor site is the Beta-1 receptors
- Main drug effects include decreased cardiac stimulation, decreased heart rate, and decreased force of contraction.
- Drug example is metoprolol (Lopressor®)

Beta-2 Adregenic Agonists:
- Receptor site is the Beta-2 receptors
- Main drug effects include the relaxation of Beta-2-mediated smooth muscle, bronchodilation, and increased blood flow to the heart and skeletal muscle.
- Drug example is terbutaline (Brethine®)

Beta-2 Adregenic Antagonists:
- Receptor site is the Beta-2 receptors
- Main drug effects include nontherapeutic Beta-2-mediated smooth muscle contraction
- Drug example is timolol (Blocadren®)

# data[].attributes.body
Henry, Hitner,, and Nagle, Barbara. Pharmacology: An Introduction. Available from: VitalSource Bookshelf, (7th Edition). McGraw-Hill Learning Solutions, 2015.