Cholinergic Vs Adrenergic (Video)

What type of postganglionic nerve fiber secretes norepinephrine?

Sympathetic Nerve Fiber (Adrenergic)

What type of postganglionic nerve fiber secretes acetylcholine?

Parasympathetic

T/F: The preganglionic receptors secrete a mixture of Acetylcholine and Norepinepherine

False, pre-ganglionic receptors only secrete Acetylcholine

T/F: All pre-ganglionic nerve fibers are autonomic

False, most are autonomic, but some are somatic (one that releases onto skeletal muscle) (N_M)

2 organs are supplied by a sympathetic muscarinic fiber, what type of neurotransmitter do they secrete? Which organs are they?

• Acetylcholine

  • This is the exception to the “sympathetic fibers secrete norepinephrine“ rule

• Sweat Glands and blood vessels of skeletal muscle

What are the clinical signs of a cholinergic crisis? Hint think D.U.M.B.E.L.L.S

• Diarrhea

• Urination

• Miosis

  • Constricted/Pinpoint pupils

• Bradycardia

• Emesis

  • Nausea/Vomiting

• Lacrimation

• Lethargy

• Salivation

Don’t forget that cholinergic fibers are a part of the PNS which is “rest and digest“, everything on this list would be from the body relaxing too much

• In an adrenergic nerve fiber, what type of neurotransmitter is secreted?

• What are the 2 structures that the neurotransmitter can bind too?

• Lastly, what are the 3 ways that the neurotransmitter is removed from the synapse?

• Norepinephrine (NE)

• Alpha-1 and Beta-1

• 3 ways

  • Re-uptake

  • Broken down

  • Binds to Alpha-2 as a negative feedback loop to prevent the release of more NE

To which type of nervous system does each of the following belong?

• Nicotinic

• Muscarinic

• Cholinergic

• Adrenergic

• PaNS

• PaNS

• PaNS

• SNS

If a N_N nicotinic receptor binds to the heart, what receptor on the heart is it binding to?

A muscarinic receptor (Not sure about this)

A sympathetic pre-ganglionic nerve fiber that is binding to its ganglion bind to what type of receptor? Would it change if the preganglionic receptor was parasympathetic?

• N_N

• No

T/F: Ganglions are nicotinic receptors

True

A cholinergic pre-ganglionic nerve fiber binds to the adrenal medulla. What type of receptor does it bind to? (subtype of muscarinic or nicotinic)

N_N

Why is the first receptor nictotinic (N_N) and the 2nd is Muscarinic (M) even though both are stimulated by Ach?

• The determinant is what the Ach binds to, in the first receptor, the Ach binds to a nicotinic receptor and induces a the release of nicotine

• In the second receptor, the Ach stimulates a muscarinic receptor which releases a muscarinic

What are the effects of Nicitonic N_M Antagonists?

• It blocks the NMJ

  • Causing paralysis

  • The NMJ is where a motor neuron binds to skeletal muscle

  • So these drugs prevent cognizant movement of muscles

Both nicotinic and muscarinic receptors are stimulated by….

Acetylcholine

T/F: Nicotinic Receptors, both N_N and N_M are usually Pre-Ganglionic Receptors

True

T/F: Adrenergic fibers can releases adrenaline as well as nor-adrenaline

False, they only release nor-adrenaline (nor-epinepherine)

Which receptor subtypes, cholinergic or adrenergic, cause the contraction of smooth muscle?

M₁,M₃, and Alpha-1

Which receptors are G_q coupled?

M₁,M₃, and Alpha-1

All Beta-receptors (of the adrenergic receptor) are G_{_} coupled

• G_s

  • They increase adenyl cyclase which increases cyclic-AMP (cAMP)

Why does the heart and bronchi “love“ cyclic-AMP (cAMP) which is produced by G_s receptors?

• It increases cardiac properties such as

  • Ca2+

  • Contractility

• Lungs bc it dilates them

Alpha receptors are usually _____, while Beta receptors are normally ______, are there any exceptions?

• Excitatory

• Inhibitory

• Yes

  • Beta receptors are inhibitory for everything, but excitatory for these 3 things

    • Heart

    • Hormone

    • Metabolism

Why does N.E need 2 different receptors that essentially accomplish the same thing (alpha/beta)?

• When an animal is running from a predator, its body will trigger fight/flight and produce N.E, that neurotransmitter will perform a variety of tasks, but one example would preventing urination

• To prevent urination it has to relax the bladder wall (beta receptor) and also constrict the urethral sphincter (alpha receptor) by working in tandem this will prevent urination

T/F: Alpha-1 and Alpha-2 work together to stimulate a stronger SNS response

• False, they are antagonists

  • Alpha-1 is pro-sympathetic (G_q)

  • Alpha-2 is anti-sympathetic (G_i)

Why is the Alpha-2 receptor inhibitory?

It is a negative-feedback mechanism that prevent prolonged response of a synapse from N.E

Where is Beta-1 receptor located? Beta-2?

• The heart

• The Lungs

Alpha and Beta receptors are types of _______ receptors

Adrenergic

What effect would Alpha-agonists have on the animal?

They would promote SNS function (fight/flight)

Which of these agonists and blockers perform similar functions?

• Alpha Agonist

• Alpha Antagonist

• Beta Agonist

• Beta Antagonist

• Beta Agonists and Alpha Antagonists

• Beta Antagonists and Alpha Agonists

T/F: Ganglionic Blockers (N_N blockers) can inhibit some of both cholinergic/adrenergic receptors

True! If those receptors are attached to a ganglion and then N_N is inhibited/blocked then it can stop everything downstream