Pharmacology Flashcards
What neurotransmitter(s) is used in preganlionic neurons in the sympathetic and parasympathetic nervous system?
Acetyl Choline
What neurotransmitter is used in the sympathetic nervous system at the end organ?
Norepinepherine
What does the adrenal medulla secrete?
Systemic epinephrine and norepinephrine
What neurotransmitter does the SNS secrete at the adrenal medulla to cause endocrine secretion?
Acetyl Choline
What does sympathetic activation cause in the body?
“Fight or Flight”
Increase HR
Dilate eyes
Relax bronchioles
Decrease GI motility and tone
Generalized secretion of sweat glands
Increased blood flow systemically
What kind of autonomic receptors will you find on skeletal muscle?
Nicotinic ACh (muscular variant)
What kind of neurotransmitter receptor will you find on a parasympathetic post ganglionic neuron?
Muscarinic
What does parasympathetic activation cause in the body?
“Rest and Digest”
Decreased HR
Contraction of bronchioles
Increaesd GI tract motility and tone
Localized sweat secretion
Contraction of iris
What do presynaptic muscarinic receptors do?
Block Ca2+ channels from allowing Ca2+ into the cell, effectively preventing vesicle fusion and ACh release
- they also cause secondary messenger cascades depending on type of receptor (odd or even)
Describe how the nicotinic receptor works
It is an ionotropic receptor
- Made up of 5 subunits that form an ion channel
- Binding of ACh (or nicotine) to receptor opens the channel and allows Na+ to flow into the cell
What kind of neurotransmitter receptors do sweat glands have?
Sympathetic ACh muscarinic (this is an exception to the rule)
Sympathetic end organ receptors are usually adrenergic.
What is the mechanism for muscarinic cholinergic receptors at the end organ?
M1, M3, M5:
Activation of the odd muscarinic receptors results in g-coupled protein cascades that activate the formation of IP3 and DAG, leading to increased intracellular calcium
M2, M4:
Activation of the even muscarinic receptors results in g-coupled protein cascades that activate opening of K+ Chanels, and inhibition of adenylyl cyclase (resulting in decrease of cAMP)
What iris muscles are under sympathetic control? What do they do?
Radial muscles cause iris to dialate when they contract mydriasis.
What iris muscle is under parasympathetic control? What does it do?
The sphincter muscle (sayswhat?) tightens and causes myosis.
How do cocaine and tricyclic antidepressants affect NE levels?
Increase activity at the terminal by blocking reuptake by NE Transporters (NET).
How and where does NE form?
Adrenal medulla and sympathetic post ganglionic terminals.
Tyrosine–>DOPA–>Dopamine–>NE–>
Epinepherine (only in adrenal medula)
What is COMT and what does it do?
Catecholo-methyl transferase.
It’s located in the liver and inactivates endogenous and exogenous catecholamines.
What does MAO do and where is it located?
(monoamine oxidase)
Oxidizes NE if not repackaged in a vessicle after it is reabsorbed by the nerve terminal.
It decreases free NE levels.
It is located in the mitochondria in the post ganglionic sympathetic neurons.
How does amphedamine elicit it’s effect at the cellular level?
It enters the nerve terminal and NE storage vessicles and forces NE out.
It also blocks MAO.
Where are adrenergic receptors found (generally)?
(Alpha, beta, and dopamine)
Found on cardiac tissue, smooth muscle, and glands
Alpha:
a1 = post-synaptic
a2 = pre- or post-synaptic (ß cells of pancreas)
Beta:
ß1 = post-synaptic
ß2 = extra-junctional on end organs
(circulating EPI acts on ß2)
Dopamine:
D1 = post-synaptic
D2 = pre- and post-synaptic
What receptors does Epinepherine act on?
Beta 1, 2, 3
Alpha 1 and 2
What receptors does NE work on?
Alpha 1, Alpha 2, and Beta 1
What receptors does dopamine act on?
D1, D2, and B1
What adrenergic receptors are found on the blood vessels and what do they do?
Alpha 1 - Arteriolar constriction, Venoconstriction
Alpha 2 - Vasoconstriction
Beta 2 - Arteriolar dialation in skeletal muscle and liver and venodialation
D1- Kidney and Mesentaric dialation
