What is a neurotransmitter? Chemicals secreted by neurons Stimulated action potential in adjacent...
-
Upload
myrtle-shaw -
Category
Documents
-
view
233 -
download
0
description
Transcript of What is a neurotransmitter? Chemicals secreted by neurons Stimulated action potential in adjacent...
What is a neurotransmitter?Chemicals secreted by neurons
Stimulated action potential in adjacent neurons
Two types of responses:ExcitatoryInhibitory
Types of ResponsesExcitatory:
Opens sodium gatesStarts a nerve
impulseInhibitory
Makes neuron more negative on inside Raises Threshold
Requires more stimulus to start a nerve impulse
SummationEffect produced by the accumulation of
neurotransmitters from two or more neurons
EXAMPLESNeurotransmitter
Excitatory or Inhibitory
Effect
Acetylcholine Both excitatory and inhibitory
•Involved with somatic & parasympathetic nervous systems•Stimulates skeletal muscles•Inhibits cardiac muscles
Norepinephrine (noradrealine)
Excitatory •Involved with sympathetic nervous system
Neurotransmitter
Excitatory or Inhibitory
Effect
Glutamate Excitatory •Cerebral cortex (brain) excitatory transmissions•75% of all transmissions
GABA (Gamma aminobutyric acid)
Inhibitory •Cerebral cortex inhibitory transmissions
Dopamine Excitatory •Elevates mood•Controls skeletal muscles
Seratonin Inhibitory •Involved in alertness , sleepiness, mood, thermoregulation
DisordersAlzheimer’s Disease
Low acetylcholine
Parkinson’s DiseaseLow dopamine
Drugs….Which are good? Which are bad?
Prescription drugsMade to alter neurotransmitter release
Addictive drugsInterfere with neurotransmittersProduce feeling of pleasure
Release dopamine
Prescription DrugsValium
Increases GABAResult: alleviate anxiety
ProzacEnhances serotoninResult: antidepressant
Drug and Poison OverviewMuscle paralysis
E.g. Nerve gas, botulin toxin, some insecticides
Result: disrupts acetylcholine
StimulantsMimics norepinephrineResult: alertness,
excitement
DepressantsBlock
norepinephrine formation
Result: slows body activity, depression
HallucinogensInterferes with
serotonin
MethamphetamineEnters synaptic vessiclesCauses dopamine releaseBlocks dopamine from reentering synaptic
knobResult:
Increased pleasure
CocaineEnters synapseBlocks dopamine from reentering synaptic
knobResult:
Increased pleasure
NictoineBinds to receptor
on presynaptic neuron
Causes more dopamine to be released