4. Synaptic Neurotransmission and
Neurodevelopment
• Neurogenesis, neuronal selection and
migration occur before birth.
• Differentiation, myelination and
synaptogenesis continue throughout entire
life
• Competitive elimination is a process of brain
restructuring that occurs in adolescence.
6. Protein synthesis
• Peripheral proteins (proteins who live in the
cytoplasm) are made on free polysomes and
transported into the axon and dendrites.
• Integral or secretory proteins (proteins that
are inserted into a membrane) are made on
the rough endoplasmic reticulum, transported
to the Golgi apparatus where they are packed
into vesicles – ready for transport.
12. Retrograde Neurotransmission
• The postsynaptic neuron can communicate
with the presynaptic neuron (such is the case
with endogenous canabinoids, NO and NGF).
14. Volume Neurotransmission of
Dopamine in The Prefrontal Cortex
• There are few dopamine reuptake pumps in
the prefrontal cortex. The excess dopamine
diffuses and finds receptors on other neurons.
15. Volume Neurotransmission to
Autoreceptors on Monoamine
Neurons
• Autoreceptors are situated on the same
neuron and cause inhibition of transmission.
• For instance dopamine diffuses out of the
synapse in the prefrontal cortex and
stimulates the autoreceptors on the same
neuron, thus inhibiting dopaminergic
transmission.
18. Signal Transduction
• Refers to communication between the
genome of the presynaptic neuron and the
genome of the postsynaptic neuron.
• It can happen both ways: the genome of the
postsynaptic neuron can also communicate
back with the genome of the presynaptic
neuron.
• Signal transduction is a slow process taking
hours or days.
20. Signal Transduction Cascade
• The cascade of events that take place after the
stimulation of the postsynaptic receptors.
• The third messenger can be a KINASE which adds
phosphate groups to proteins to create
phosphoproteins.
• The third messenger can also be a PHOSPHATASE
which removes phosphate groups from
phosphoproteins
• The balance between kinases and phosphatases
determines the downstrean chemical activity.
21. Four Types of Signal Transduction
Cascade
• G protein linked systems
• Ion channel-linked systems
• Hormone linked systems
• Neurotrophin-linked systems
Neurotransmitters activate G protein linked
systems and ion channel linked systems. Both of
these systems activate genes in the cell nucleus.
22. Signal Transduction Cascades
• The G protein linked system works through a cascade involving cAMP and Protein
kinase A.
• The ion channel systems works through Calcium and calcium modulin kinase.
Both of these systems activate genes in the cell nucleus by phosphorylating a
protein there called CREB (cAMP response element-binding protein).
• Certain hormones (like estrogen and steroids) enter the neuron, bind to their
receptors in the cytoplasm, forming a hormone nuclear receptor complex. This
complex enters the nucleus and interact with hormone response elements (HRE)
to trigger activation of specific genes.
• The neurotrophin system activates a series of kinase to trigger gene
expression, which may control synaptogenesis and neuron survival. Ras is a G
protein, Raf is a kinase, MAPK is mitogen activated protein kinase and GSK3 is
glycogen synthase kinase 3.