Lecture 1-Vasoconstrictors Flashcards
What are the three arms of the autonomic nervous system?—sympathetic innervation of ___; ___ nervous system; ___ nervous system
- Sympathetic innervation of adrenal medulla (causes the release of epinephrine into the blood)
- Sympathetic nervous system
- Parasympathetic nervous system
What neurotransmitter kicks off all of the arms of the autonomic nervous system? What receptor does it bind to?
Acetylcholine; binds to nicotinic receptors
Catecholamines bind to ___ receptors; acetylcholine binds to ___ and ___ receptors
Catecholamines bind to adrenergic receptors; acetylcholine binds to nicotinic and muscarinic receptors
The sympathetic nervous system has thoracolumbar origin from T___-L___
T1-L2
Preganglionic neurons of the sympathetic nervous system are near the ___
Spinal cord
Postganglionic neurons secrete ___-adrenergic fibers
Norepinephrine-adrenergic fibers
How is norepinephrine created?—dopamine ___ converts ___ to ___
Dopamine beta hydroxylase converts dopamine to NE
Norepinephrine signal termination—80% of norepi that is released is ___
Recycled (via reuptake)
Norepinephrine signal termination—a ___ (small/large) amount of NE dilutes away by diffusion
Small amount
Norepinephrine signal termination—20% of NE that is not recycled is metabolized by ___ and ___
MAO (monoamine oxidase) and COMT (catechol-o-methyltransferase)
What are the 4 adrenergic receptors?
- Alpha 1
- Alpha 2
- Beta 1
- Beta 2
Alpha 1 receptors are located in the ___
Periphery
Alpha 2 receptors are located in the ___ (central/peripheral) nervous system
Central
Beta 1 receptors are located in the ___
Heart
Beta 2 receptors are located in other ___ muscle
Other smooth muscle
What binds to adrenergic receptors?
Catecholamines!
When catecholamines bind to beta adrenergic receptors, the result is ___ mediated effects; stimulatory proteins activate ___, causing a change from ATP into cyclic ___; cyclic ___ pulls ___ into the cells (cardiac myocytes, peripheral vasculature, skeletal muscle) to cause contraction of skeletal muscle or dilation in the periphery
G-protein mediated effects; stimulatory proteins activate adenylyl cyclase, causing a change from ATP into cyclic AMP; cyclic AMP pulls calcium into the cells to cause contraction of skeletal muscle or dilation in the periphery
Cyclic AMP is metabolized into ___, then ___, which has no further action
Phosphodiesterase 3, then AMP
When catecholamines bind to alpha receptors, the reaction is again ___ mediated; a ____ causes increases in calcium, which leads to contraction
G-protein mediated; a second messenger causes increases in calcium, which leads to contraction
SNS—alpha 1 postsynaptic receptor—activation ___ (increases/decreases) intracellular calcium; causes smooth muscle ___ (contraction/relaxation); peripheral vaso___ (constriction/dilation); broncho___ (constriction/dilation); ___ (stimulates/inhibits) insulin secretion from beta islet cells of the pancreas; ___ (stimulates/inhibits) glycogenolysis and gluconeogenesis; my___ (driasis/osis); GI ___ (relaxation/contraction)
Activation increases intracellular calcium; causes smooth muscle contraction; peripheral vasodilation; bronchoconstriction; inhibits insulin secretion from beta islet cells of the pancreas; stimulates glycogenolysis and gluconeogenesis; mydriasis—opens up the eyes; GI relaxation
SNS—alpha 2 receptors—presynaptic in the ___; postsynaptic in the ___
Presynaptic in the PNS; postsynaptic in the CNS
Alpha 2 receptors—presynaptic in the PNS—stimulation of these receptors ___ (increases/decreases) entry of calcium into the cell; limits the release of ___
Decreases entry of calcium into the cell; limits the release of norepinephrine
Alpha 2 receptors—postsynaptic in the CNS—stimulation of these receptors causes ___ation; ___ (increased/decreased) sympathetic outflow; ___ (increased/decreased) BP; platelet ___
Sedation; decreased sympathetic outflow; decreased BP; platelet aggregation
Two medications that are alpha 2 receptor agonists = ___ and ___
Dexmedetomidine (precedex) and clonidine