Transcript Neurons Speak - People Server at UNCW

Neurons Speak 
The Neuron is the Fundamental “working unit” of the nervous
system
In most respects the neuron is like
other cells of our body
But is different in that it can produce electrical
impulses near its cell body region
That move down the axon and lead to the release of
specialized neurochemicals (neurotransmitter
substances) at the Synapse
Synaptic release of Neurotransmitter substances
may in turn affect “postsynaptic” neurons; mostly in
the dendritic regions
The Neuron is also different in that the axon
is typically myelinated by “glial cells”
The Neuronal communication process can
be thought of as an “electro-chemical” event
• How is the electric signal produced?
• How is the Chemical event produced?
The Neuron is Like a little battery
The resting Membrane potential
(RMP)
Ions are responsible for the charge
of a neuron
Cations +
Anions-
At Rest, ionic substances have different concentrations inside
vs. outside the neural membrane
The forces of Diffusion:
Concentration Gradients
“Threshold” triggers the “Action
Potential”
By activating Ion channels
Once triggered, the AP is all or none,
and “one-way.”
Myelenation and size affect speed
Action Potential at the Terminals
The Synapse: PRESYNAPTIC and POSTSYNAPTIC
processes
PRESYNAPTIC Exocytosis
Classical NTs
NTs
Terminology
Post synaptic effects
Acetylcholine/ACH
Cholinergic
Serotonin/5-HT
serotonergic
GABA (gamma-amino-butyric acid)
GABA-ergic
Glutamate/Glu
Glutamatergic
Norpinephrine /NEAdrenergic
Dopamine /DA
Dopaminergic
Enkephalin/Endorphin
+/+/-
+
+/-
+/+/-
Many other neurotransmitters are derived from precursor proteins, the so-called
peptide neurotransmitters. As many as 50 different peptides have been shown to
exert their effects on neural cell function.
POSTSYNAPTIC PROCESSES:
NT receptors
Specificity- Lock and Key analogy
EFFECTS OF NTs?
Many factors, but all lead to:
• IPSPs: inhibiitory post synaptic potentials
– Decrease probability of action potential
• EPSPs: excitatory post synaptic potentials
– Increase probability of action potential
Neural Integration
NT-receptor interactions must stop!
Enzymatic degradation
Eg…
Effects of Nerve gas exposure
Neuromuscular
Effects
•Twitching
•Weakness
•Paralysis
•Respiratory
failure
Autonomic
Nervous
System Effects
•Reduced Vision
•Small pupil size
•Drooling
•Sweating
•Diarrhea
•Nausea
•Abdominal pain
•Vomiting
Central Nervous
System Effects
•Headache
•Convulsions
•Coma
•Respiratory
arrest
•Confusion
•Slurred speech
•Depression
•Respiratory
depression
Reuptake
Here are the SSRIs approved by the Food and Drug Administration (FDA)
specifically to treat depression, with their generic, or chemical, names followed by
available brand names in parentheses:
Citalopram (Celexa)
Escitalopram (Lexapro)
Fluoxetine (Prozac, Prozac Weekly)
Paroxetine (Paxil, Paxil CR, Pexeva)
Sertraline (Zoloft)
These medications may also be used to treat conditions other than depression.
Side effects of SSRIs
All SSRIs have the same general mechanism of action and side effects. However,
individual SSRIs have some different pharmacological characteristics. That means
you may respond differently to certain SSRIs or have different side effects with
different SSRIs.
SSRI possible side-effects
Side effects of SSRIs include:
Nausea
Sexual dysfunction, including reduced
desire or orgasm difficulties
Dry mouth
Headache
Diarrhea
Nervousness
Rash
Agitation
Restlessness
Increased sweating
Weight gain
Drowsiness
Insomnia
Drugs may affect neural transmission
in different ways