Intro to CNS: Neurotransmitters Flashcards
Drug selectivity is based on the fact that different pathways use different transmitters, a primary goal of neuroscience has been to identify the neurotransmitters in CNS pathways
Central Neurotransmitters
Criteria for Transmitter Status:
Present in higher concentration in the synaptic area than in other areas
Localization
Criteria for Transmitter Status:
A suspected transmitter must reside in the presynaptic terminal of the pathway of interest
Localization
Criteria for Transmitter Status:
A suspected transmitter must be released from a neuron in response to neuronal activity and in a calcium-dependent manner.
Release
Criteria for Transmitter Status
Produce the same sort of postsynaptic response that is seen with physiologic activation of the synapse
Synaptic mimicry
Criteria for Transmitter Status:
Application of the candidate substance should produce a response that mimics the action of the transmitter released by nerve stimulation, and application of a selective antagonist should block the response
Synaptic mimicry
Criteria for Transmitter Status
Released by electrical or chemical stimulation via a
calcium-dependent mechanism
Chemicals accepted as NTAs in the CNS
- 5% of neurons have receptors for ___
- G protein-coupled muscarinic M1 receptors
Acetylcholine (Ach)
Chemicals accepted as NTAs in the CNS
↓ slows excitation
↓ decreases permeability to potassium
Acetylcholine (Ach)
Chemicals accepted as NTAs in the CNS
Inhibitory actions at synapses in specific neuronal systems
Dopamine
Chemicals accepted as NTAs in the CNS
G protein-coupled activation of K+ channels
Dopamine
Chemicals accepted as NTAs in the CNS
↑ increases cAMP
Dopamine
Chemicals accepted as NTAs in the CNS
D2 receptor is the main dopamine subtype
Dopamine
Chemicals accepted as NTAs in the CNS + Effect
Activation of α1 and β1 receptors
Norepinephrine, Excitatory
Chemicals accepted as NTAs in the CNS + Effect
↓ decreases K+ conductance
Norepinephrine, Excitatory
Chemicals accepted as NTAs in the CNS
Activation of α2 and β2 receptors
Norepinephrine, Inhibitory
Chemicals accepted as NTAs in the CNS
↑ increases K+ conductance
Norepinephrine, Inhibitory
Chemicals accepted as NTAs in the CNS
Multiple 5 hydroxytryptamine (5-HT) receptor subtypes
Serotonin
Chemicals accepted as NTAs in the CNS
Inhibitory at many CNS sites
Serotonin
Chemicals accepted as NTAs in the CNS
Metabotropic
Serotonin
Chemicals accepted as NTAs in the CNS
Excitatory depending on the receptor subtype activated
Serotonin
Chemicals accepted as NTAs in the CNS
Excitatory for most neurons
Glutamic Acid
Chemicals accepted as NTAs in the CNS
N-methyl-D-aspartate (NMDA) receptor
Glutamic Acid
Chemicals accepted as NTAs in the CNS
Inhibition of adenyl cyclase
Glutamic Acid
Chemicals accepted as NTAs in the CNS
The Primary NTA mediating IPSPs
GABA
Chemicals accepted as NTAs in the CNS
Opens K+ channels
GABA(B) receptor activation
Chemicals accepted as NTAs in the CNS
Opens Cl- conductance
GABA(A) receptor activation
Chemicals accepted as NTAs in the CNS
Closes Ca2+ channels
GABA(B) receptor activation
Chemicals accepted as NTAs in the CNS
More numerous in the cord
Glycine
Chemicals accepted as NTAs in the CNS
↑ increases Cl- conductance
Glycine
Chemicals accepted as NTAs in the CNS
Beta-endorphins, dynorphins
Opioid Peptides
Chemicals accepted as NTAs in the CNS
↓ decreases Ca2+ conductance
Opioid Peptides Inhibitory (presynaptic)
Chemicals accepted as NTAs in the CNS
↑ increases K+ conductance
Opioid Peptides Inhibitory (postsynaptic)
Type of Neurotransmitters
Glutamate
Amino Acid Neurotransmitter
Type of Neurotransmitters
GABA and Glycine
Amino Acid Neurotransmitter
Type of Neurotransmitters
Ionotropic Receptor
GABA(A)
Type of Neurotransmitters
Metabotropic Receptor
GABA (B)
Type of Neurotransmitters
Catecholamines
Monoamine Neurotransmitter
Type of Neurotransmitters
Dopamine
Monoamine Neurotransmitter
Type of Neurotransmitters
Norepinephrine
Monoamine Neurotransmitter
Type of Neurotransmitters
5-Hydroxytryptamine
Monoamine Neurotransmitter
Type of Neurotransmitters
Neurotensin
Neuropeptides
Type of Neurotransmitters
Opioid Peptides (Enkephalins, Endorphins)
Neuropeptides
Type of Neurotransmitters
Histamine
Monoamine Neurotransmitter
Type of Neurotransmitters
Substance P
Neuropeptides
Type of Neurotransmitters
Neuropeptide Y
Neuropeptides
Type of Neurotransmitters
Somatostatin
Neuropeptides
Type of Neurotransmitters
Cholecystokinin
Neuropeptides
Type of Neurotransmitters
Vasoactive Intestinal polypeptide
Neuropeptides
Type of Neurotransmitters
Thyrotropin-releasing hormone
Neuropeptides
Type of Neurotransmitters
Orexin (Hypocretins)
Neuropeptides
Type of Neurotransmitters
Endocannabinoids
Signaling Substance
Type of Neurotransmitters
Nitric Oxide, Purine
Signaling Substance
Amino Acid Neurotransmitters:
The high concentration of
glutamate in synaptic vesicles is achieved by the ______________.
vesicular glutamate transporter (VGLUT)
Amino Acid Neurotransmitters:
Is released into the synaptic cleft by Ca2+-dependent exocytosis
Glutamate
Amino Acid Neurotransmitter Categories
- Amino acid glutamate
- Neutral amino acids glycine & GABA
