Exam 2 Flashcards
(112 cards)
What is a neurotransmitter?
Chemical released onto target cell
Criteria for neurotransmitters
- Substance exists in presynaptic axon terminals
- Substance synthesized in presynaptic cells
- Substance released when action potential reaches axon terminals
- Receptors for the substance exist on postsynaptic membrane
- When applied, substance causes changes in postsynaptic cell
- Blocking substance release prevents changes
If a neurotransmitter does not follow all of the criteria for neurotransmitters, what is it called?
Atypical neurotransmitter (violate at least one rule that is a criteria for neurotransmitters)
Name the types of typical neurotransmitters
Amino acid neurotransmitters, amine neurotransmitters, peptide neurotransmitters
Amino acid neurotransmitter examples
GABA (gamma-aminobutyric acid), Glutamate, Glycine
What do all amino acids have?
NH2 and COOH
Amine neurotransmitters
Based on modifications of a single amino acid nucleus
Peptide neurotransmitters
Based on multiple amino acids/short chains of amino acids
Atypical neurotransmitter type and examples
Gas and lipid neurotransmitters such as nitrous oxide
Name some nearly ubiquitous nts
Glutamate: fast depolarization/excitation, GABA/glycine: inhibitory/causes hyperpolarization
True or false: we can study brain tissue in a way such that only neurons responsible for making a certain neurotransmitter are present/labled
True
How many neurotransmitters does a neuron make?
Typically only 1
Why is it easy for diseases like Alzheimer’s and parkinson’s to occur?
Pathways are based on a relatively small number of neurons/nerves
Describe the cholinergic pathway
Basal forebrain to hippocampus, cortex, and amygdala. . In the peripheral nervous system, acetylcholine is present at the neuromuscular junction and in the central nervous system, ACh has different effects including
- Reward system (which nicotine activates by activating NACh receptors on the brain’s surface
- When acetylcholine binds to specific neurons in the VTA it releases dopamine
- Muscarinic acetylcholine receptors: cognition, so blockers can produce hallucinations; they aid in transduction of cholinergic signals and are GPCR’s
Dopaminergic pathway
Two pathways
- Mesolibocortical pathway: VTA to NAcc and cortex, especially important for processing reward, and abnormalities are associated with some symptoms of schizophrenia
- That is why antipsychotics typically target DA receptors
DA is important for learning shaped by positive reinforcement
Mesostriatal pathway- substantia niagra to basal ganglia
- neurons in niagra release dopamine in striatum and innervate the striatum
- loss of neurons associated with parkinson’s
Serotonergic
Midbrain raphe nuclei to forebrain
Brainstem raphe nuclei to spinal cord
Cell bodies mainly found in nuclei then they spread all over
Serotonin is implicated in sleep, mood, sexual behavior, anxiety which is why drugs like prozac increase amount of 5HT in synaptic cleft to increase receptor activity
Noradrenergic
Norepinephrine/noradrenaline
- Alertness, mood, sexual behavior
- Locus coeruleus to forebrain
- Lateral tegmented area to brainstem/spinal cord
Axons from these areas spread through cerebrum including cerebral cortex, limbic system, and thalamic nuclei
Glu
Glutamate
Gly
Glycine
ACh-
Acetylcholine
DA
Dopamine
NE
norepinephrine
5-HT
serotonin
How do we identify and name neurotransmitters?
Look at which nt it bonds, whether it is ionotropic or metabotropic, and whether there is specific pharmacology/special drugs that bind/affect it