CH 7 Flashcards
ACh is a key NT in both ___ and _____. In the _____ it is used in all _____ junctions and in the _______ nervous system. In the CNS, multiple cell body regions enervate _______/_____ regions ACh ____ in the striatum
PNS, CNS, PNS, neuromuscular, parasympathetic, cortical/subcortical, interneurons
a precursor to ACh that is from foods
choline
the other precursor to ACh
acetyl coenzyme A (acetyl CoA)
the enzyme that makes ACh from choline and acetyl CoA; only in ACh neurons
choline acetyltransferase (ChAT)
the rate of ACh synthesis is controlled by the availability of ____ and rate of ____ _____. ChAT works more efficiently when the neuron is firing ______. No selective ____ of ChAT have been found
precursors, neuron firing, a lot, inhibitors
transporters that package ACh into vesicles
vesicular ACh transporters (VAChT)
drug that blocks VAChT, reducing ACh levels
vesamicol
A toxin that causes massive ACh release in the PNS leading muscle pain, tremors, nausea, vomiting, salivation and copious sweating
black widow spider venom
inhibits ACh release selectively in the neuromuscular junction
botulinum toxin
Inhibition of cholinergic activity can be deadly because of ____ _____. ____ can be affected as well. Botox ____ binds to proteins involved in ACh release and prevents release
muscular paralysis, irreversibly
Unlike many transmitters, ACh does not undergo direct ____
reuptake
the enzyme that rapidly breaks down ACh to choline and acetic acid
acetylcholinesterase (AChE)
AChE is located on ______ membranes and also in _____ cells that metabolize ____ ACh. It has a very high _____ for ACh, and breaks it down within _____
postsynaptic, presynaptic, excess, affinity, ms
After ACh breakdown, most choline is taken back into the _____ ______ ____ by a choline transporter
cholinergic nerve terminal
drug that blocks choline transporters, reducing the rate of ACh production
hemicholinium-3 (HC-3)
Blocking _____ (ACh inactivation), increases ____ effects of the transmitter
AChE, postsynaptic
Drug that crosses the BBB and is used to inhibit AChE; offsets some of the cognitive decline associated with AD
physostigmine
ACh neurons die off in the early stages of ____, and multiple other cells die off in late stages
Alzheimer’s disease
Some compounds cause ______ inhibition of AChE, resulting in excess amount of ACh. Weak versions are used as ______. Very toxic varieties such as ____ are used as nerve gasses. ACh ____ and overstimulation of cholinergic synapses throughout the CNS and PNS lead to _____ ____ and death by _____
irreversible, insecticides, serin, accumulation, muscle paralysis, asphyxiation
Nicotinic receptors respond to the agonist ______, and are _____. When ACh binds, the channel allows _____ and ____ flow into the cell and depolarizes it. This type of receptor mediates ______ ____ responses in the CNS and PNS. It consists of ____ subunits (alpha, beta, gamma, sigma, epsilon), with many ____ and ___ of each found in the muscle and brain. Different subtypes can vary in terms of the number of ____ ___ or ____ for ACh, ion flow through channel, ____/____ kinetics, and _____ binding sites. These receptors typically need ____ ACh molecules to open, but the more binding sites, the more the receptor is only active when NT levels are _____.
nicotine, ionotropic, Na+, Ca2+, fast, excitatory, 5, variants, combinations, binding sites, affinity, open/close, allosteric, 2, high
continuous activation of nicotinic receptors initially cause the receptors to be _____, and the channel remains _____ even when an agonist is bound. The channel recovers after a short time with no ______. However, prolonged activation leads to ___ ______, which is persistent, and causes ____ ____ to be lost. This means the cell cannot be excited until the ___ is removed and the membrane ______.
desensitized, closed, stimulation, depolarization block, resting potential, agonist, repolarizes
a drug that causes persistent activation of nicotinic receptors
carbachol
a nicotinic receptor agonist that is a muscle relaxant used in some surgical procedures; it is resistant to breakdown by AChE and causes depolarization block
succinylcholine
a nicotinic receptor antagonist that blocks receptors in both the CNS and autonomic ganglia; used to treat nicotine poisoning
mecamylamine