CENTRAL NERVOUS NEUROTRANSMITTERS (Sm
molecules) AND NEUROPEPT
SYSTEM OVERVIEW
SYNAPSE
• Responsible for inhibition and
•
facilitation of impulses
Has role in memory/storage of
• One of the first to be discovered by primitive
humans CLASS I
information (temporal lobes). What did they discover? ACETYLCHOLINE
• Nearly all drugs act on specific receptors— • First compound to be
modulate synaptic transmission.
identified as NT (mainly
• Important in the study of CNS physiology
Excitation and Inhibition of Post Synaptic Membrane PRE-, POST- & SYNAPTIC TERMINALS • Mechanisms of diseases are discovered due to
excitatory) in the CNS.
EXCITATION
• AP reaches pre-synaptic terminal and cause depolarization (Ca2+
enters the cell) the study of MOA of drugs • Locations:
• Opening of Na+ channels. • Ca2+ triggers NT release from vesicles. - Motor cortex
• Depressed conduction through chloride or potassium channels • NT binds to receptor sites on post synaptic membrane.
• Result: Changes in internal metabolism • Opening and closing of channels can cause change in post synaptic - Basal ganglia
• Resting Membrane Potential membrane potential.
- RMP neurons: -65 or -70 mV • AP propagates through the next cell and NT is inactivated or - Motor neurons that
-
-
RMP muscles: -90 mV
PiSoCo: Potassium (in), Sodium (out), Chloride (out) •
transported back into the presynaptic terminal.
Events in Presynaptic: AP, NT (Synthesis, Storage, Metabolism, innervate skeletal
• Facilitation of Action Potential: -45 mV (change must be +20mV to Release) muscles
INHIBITION
facilitate excitatory post synaptic potential) • Events in Post-synaptic: Degradation (target in Drug action)/
Reuptake
Integrative Function of the Nervous - Pre- and post-
•
•
Opening of Cl- channels.
Increased conductance of K+ ions out of the neuron
System ganglionic neurons of
• Activation of receptor enzymes
• Cortex processes incoming the ANS
SPATIAL SUMMATION
SPATIAL VS TEMPORAL SUMMATION
information before the command is • Mediated by a large family o
• Multiple presynaptic neurons = More synapses firing to a postsynaptic
neuron = higher chance to reach an EPSP of +20 mV sent back to the effector organs. G-protein but also with ionic
TEMPORAL SUMMATION properties (BOTH ionotropic
• 1 stimulation = 8 milliseconds (signal must reach +20mV within this
time limit)
• 99% of the information is and metabotropic)
• Single presynaptic neuron = Rapid/Sequential firing to postsynaptic
neuron = combined signals to reach +20mV
discarded. • Myasthenia gravis: NORMAL
ACh in the morning; LOW in
afternoon and night (Ptosis)
TYPES OF SYNAPSES Recycling of ACh
• Made from choline and
CHEMICAL ELECTRICAL acetyl CoA by choline
SYNAPSE SYNAPSE
acetyltransferase
• Degraded by AChesterase
• Uni/ • Bidirectional
once bound to the receptor
Monodirectional • Fuses with gap in the post synaptic cleft.
• Neurotransmitters junction channels— • Choline is transported back
and neuropeptides readily enter and into the axon terminal and is
exit
used again to make ACh.
molecules) AND NEUROPEPT
SYSTEM OVERVIEW
SYNAPSE
• Responsible for inhibition and
•
facilitation of impulses
Has role in memory/storage of
• One of the first to be discovered by primitive
humans CLASS I
information (temporal lobes). What did they discover? ACETYLCHOLINE
• Nearly all drugs act on specific receptors— • First compound to be
modulate synaptic transmission.
identified as NT (mainly
• Important in the study of CNS physiology
Excitation and Inhibition of Post Synaptic Membrane PRE-, POST- & SYNAPTIC TERMINALS • Mechanisms of diseases are discovered due to
excitatory) in the CNS.
EXCITATION
• AP reaches pre-synaptic terminal and cause depolarization (Ca2+
enters the cell) the study of MOA of drugs • Locations:
• Opening of Na+ channels. • Ca2+ triggers NT release from vesicles. - Motor cortex
• Depressed conduction through chloride or potassium channels • NT binds to receptor sites on post synaptic membrane.
• Result: Changes in internal metabolism • Opening and closing of channels can cause change in post synaptic - Basal ganglia
• Resting Membrane Potential membrane potential.
- RMP neurons: -65 or -70 mV • AP propagates through the next cell and NT is inactivated or - Motor neurons that
-
-
RMP muscles: -90 mV
PiSoCo: Potassium (in), Sodium (out), Chloride (out) •
transported back into the presynaptic terminal.
Events in Presynaptic: AP, NT (Synthesis, Storage, Metabolism, innervate skeletal
• Facilitation of Action Potential: -45 mV (change must be +20mV to Release) muscles
INHIBITION
facilitate excitatory post synaptic potential) • Events in Post-synaptic: Degradation (target in Drug action)/
Reuptake
Integrative Function of the Nervous - Pre- and post-
•
•
Opening of Cl- channels.
Increased conductance of K+ ions out of the neuron
System ganglionic neurons of
• Activation of receptor enzymes
• Cortex processes incoming the ANS
SPATIAL SUMMATION
SPATIAL VS TEMPORAL SUMMATION
information before the command is • Mediated by a large family o
• Multiple presynaptic neurons = More synapses firing to a postsynaptic
neuron = higher chance to reach an EPSP of +20 mV sent back to the effector organs. G-protein but also with ionic
TEMPORAL SUMMATION properties (BOTH ionotropic
• 1 stimulation = 8 milliseconds (signal must reach +20mV within this
time limit)
• 99% of the information is and metabotropic)
• Single presynaptic neuron = Rapid/Sequential firing to postsynaptic
neuron = combined signals to reach +20mV
discarded. • Myasthenia gravis: NORMAL
ACh in the morning; LOW in
afternoon and night (Ptosis)
TYPES OF SYNAPSES Recycling of ACh
• Made from choline and
CHEMICAL ELECTRICAL acetyl CoA by choline
SYNAPSE SYNAPSE
acetyltransferase
• Degraded by AChesterase
• Uni/ • Bidirectional
once bound to the receptor
Monodirectional • Fuses with gap in the post synaptic cleft.
• Neurotransmitters junction channels— • Choline is transported back
and neuropeptides readily enter and into the axon terminal and is
exit
used again to make ACh.
