7.3 Introduction to CNS [Yeye Edition] Flashcards
True or False:
Some drugs exert their effect through direct interactions with molecular components of ion channels on axons
True
True or False:
Most drugs exert their effect mainly at the synapses
True
What are the 5 Presynaptic Acts
- Synthesis
- Storage
- Release
- Reuptake
- Metabolism of transmitter chemicals
10 steps for the Sequence of Sites of Drug Action
(1) Action potential in presynaptic fiber
(2) Synthesis of transmitter
(3) Storage
(4) Metabolism
(5) Release
(6) Reuptake into the nerve ending or uptake into a glial cell
(7) Degradation
(8) Receptor for the transmitter
(9) Receptor-induced increase or decrease in ionic conductance
(10) Retrograde signaling
Inhibits synthesis of serotonin
Parachlorophenylalanine
Inhibits storage of catecholamines
Reserpine
Inhibits release of catecholamines
Amphetamine
Inhibits degradation of Acetylcholine, used for myasthenia gravis
Anticholinesterase
[It increases conc. of levels of acid]
Arranged or systematized either on hierarchical or diffused
CNS Organization
2 types of Neuronal System
- Hierarchical System
- Diffuse/ Non-specific neuronal System
Contain large myelinated, rapidly conducting fibers and MAJOR excitatory transmitters
Hierarchical System
Control major sensory and motor functions
Hierarchical System
What are the 2 small inhibitory interneurons transmitter
Gamma amino butyric acid (GABA)
Glycine
Broadly distributed, with single cells frequently sending processes to many different parts of the brain-tangential
Diffuse/ Non-specific neuronal System
Periodic enlargements that contain
transmitter vesicles
VARICOSITIES
Found primarily in a compact cell group called locus coeruleus in the caudal pontine central gray matter
Transmitters
What are the 3 central neurotransmitters
- Localization
- Release
- Synaptic Mimicry
3 Criteria for transmitter status
- Present in higher concentration in the synaptic area than in other areas (localized in appropriate areas)
- Released by electrical or chemical stimulation via calcium-dependent mechanism
- Synaptic mimicry
Produce the same sort of postsynaptic response that is seen with physiologic activation of the synapse
Synaptic mimicry
What are the 5 chemicals accepted as the NTAa in the CNS
- Acetylcholine
- Dopamine
- Norepinephrine
- Serotonin
- Glutamic Acid
NTAs: Slow excitation, 5% of neurons have receptors: G protein-coupled muscarinic M1 receptors
Acetylcholine
NTAs: Decreased permeability to potassium
Acetylcholine
NTAs: Inhibitory actions at synapses in specific neuronal systems
Dopamine
NTAs: G protein-coupled activation of K+ channels: D2 receptors
Dopamine
NTAs: Increase cAMP
Dopamine
NTAs: Generally Excitatory effects, especially in Activation of a1 and β1 receptors
Norepinephrine
NTAs: It decreases K+ conductance [flow]
Norepinephrine
NTAs: More positive = Excitatory
Norepinephrine
NTAs: What are the 2 inhibitory effects of Norepinephrine
- Activation of a2 and β2 receptors
- Increase K+ conductance
NTAs: Excitatory for most neurons, N-methyl-D-aspartate (NMDA) receptor
Glutamic Acid
NTAs: Inhibition of adenyl cyclase
Glutamic Acid
