lecture 6 Flashcards
Autonomic Nervous System
involuntary: sympathetic/thoracolumbar outflow and parasympathetic/craniosacral outflow
two neuron pathway?
acetylcholine works on ________ receptors while norepinephrine mainly on ______
nicotinic; adrenergic
sympathetic releases _______. para releases _______
norepinephrine; acetylcholine
muscarinic receptors in the heart
M2 - coupled to G alpha i (inhibits adenylyl cyclase and decreases cAMP)
muscarinic receptors in the lungs
M3 - coupled to Gq (activates phospholipase C - calcium release thus contraction)
muscarinic stimulation of the parasympathetic nervous system in the lungs promotes _________
bronchoconstriction
muscarinic receptors (M1-M5) and what they do
GPCRs, M1, M3, and M5 all activate PLC (contraction of smooth muscle), M2 (ACh) is in the heart and slows conduction, decreasing contraction force of the heart
four adrenergic receptors
alpha1 (blood vessels), beta 1 (in heart), beta 2(in lungs, one in each), alpha 2 are presynaptic
cocaine and ecstasy will increase levels of norepinephrine how?
blocking the transporters, so it builds up in the vesicle
amphetamine-adderall for ADHD, or methyphenidate (ritalin) mechanism
tyramine displaces NE.
monoamine oxidase (MOAs) break down ________ and examples
tyramine, NE and dopamine
MAO A - phenelzine
MAO B - selegiline for parkinson’s
too much tyramine can cause
(wine and cheese effect)
hypertension
if you dont have enough MAOs to break it down you can die
actions of cocaine and amphetamines
c- blocks the DA (dopa) transporter, so DA that has been released stays out a lot longer
amph- reverses the DA transporter, so more DA is released and stays out longer, also blocks degradation of DA
amphetamines mechanism of action
normal dopaminergic synapse. amphetamine enters via DAT as a substrate. enters vesicles via VMAT1 to displace DA and inhibits MAO. DA concentration rises in the cytosol. DA is expelled into synapse via reverse transport.
“pleasure center” is the ____ in the brain
VTA (ventral tegmental area)
reward and mesolimbic dopamine
activation of reward pathway leads to increased dopamine in Nucleus Accumbens
DA usually released in a ______ way, and acts on __ receptors. Increasing activity (something important or a drug like coke), would release DA in a _____ way, and activates __ receptors.
tonic, D2; phasic, D1
all autonomic receptors are coupled to _____________
GTP binding proteins
alpha 1 (G-alpha-q)
smooth muscle contraction. activate phospholipase C –> intracellular calcium
cocaine eyes
alpha 2
brain.
inhibit adenylyl cyclase
beta 1 (NE) (G alpha s)
increase heart rate, conduction velocity, and contractility.
SA, AV node and HIS-purkinje cells.
stimulate adenylyl cyclase
also found in the kidney for renin.
beta 2 (G alpha s)
lung relaxation.
stimulate adenylyl cyclase.
cAMP –> PKA –> inactivates MLCK and decreases affinity for calcium/CaM
alpha 1 receptors could increase blood pressure. why?
they release calcium, causing contraction and thus constriction of blood vessels
presynaptic alpha2 receptors decrease release of ________
norepinephrine, bc the beta gamma subunit binds to the calcium channel inhibiting it
