introduction to autonomic pharmacology: part iii mechanism of neurotransmission at
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INTRODUCTION TO AUTONOMIC PHARMACOLOGY: Part III Mechanism of neurotransmission at in the autonomic nervous system. General Features of Peripheral Autonomic Neurotransmission. NT = Neurotransmitter. General Features of Peripheral Autonomic Neurotransmission. - PowerPoint PPT PresentationTRANSCRIPT
INTRODUCTION TO AUTONOMIC PHARMACOLOGY: Part III
Mechanism of neurotransmission atin the autonomic nervous system
General Features of PeripheralAutonomic Neurotransmission
NT = Neurotransmitter
General Features of PeripheralAutonomic Neurotransmission
Membrane Depolarization ofPre- or Postganglionic Fiber
Calcium Entry intoVaricosity
Exocytosis of NTDiffusion of NT AcrossNeuroeffector Junction
or Synapse
Activation of NT Receptors
Depolarization of Postganglionic Fiber or Response of
Effector Cell
Nerve Impulse
Sympathetic Postganglionic Fiber Effector Cell
Neuroeffector Junction
COMT
(Liver)
SUMMARY OF ADRENERGIC NEUROTRANSMISSSION
Summary of Catecholamine BiosynthesisTyrosine
DOPA
Dopamine
Norepinephrine
Epinephrine
ADRENALGLAND
SYMPATHETICNERVE
Parasympathetic/Sympathetic Preganglionic Fiber or
Parasympathetic Postganglionic Fiber
Neuroeffector Junction
Parasympathetic orSympathetic
Postganglionic Fiberor Effector Cell
SUMMARY OF CHOLINERGIC NEUROTRANSMISSSION
COTRANSMISSION
Release of More Than OneNeurotransmitter from the Same
Nerve Terminal
Cotransmitter B
Synergistic or Opposite Actions
Cotransmitter A
Types of Postsynaptic Synergism
Norepinephrine/NPY
Norepinephrine/ATP
Example of Postsynaptic Synergism:(NPY enhances actions of NE)
NPY 10 nMNE
NE
Per
fusi
on P
ress
ure
(m
mH
g)
Example of Postsynaptic Synergism:ATP mediates fast responseNE mediates slow responseControl
Prazosin
Prazosin +Suramin
Control
Suramin
Prazosin +Suramin
Many Examples of NANC Neurotransmitters
Many Examples of NANC Neurotransmitters
MODULATION OF NEUROTRANSMISSION
Modulation of Neurotransmisson
Presynaptic/Prejunctional Modulation
Postsynaptic/Postjunctional
Modulation
Presynaptic/Prejunctional
InhibitionPresynaptic/Prejunctional
Facilitation
Postsynaptic/Postjunctional
InhibitionPostsynaptic/Postjunctional Facilitation
MODULATION OF NEUROTRANSMISSION
From Nerve Terminal Being
Modulated(e.g.,
Autoinhibitory Feedback)
From Postsynaptic/Postjunctional
Site (e.g., Trans-synaptic/
Transjunctional Inhibitory Feedback)
From Nearby Nerve
Terminal (Cross-
talk)
From Remote Site via
Circulation(e.g., Renin
Release)
Sources of Modulators of
Neurotransmission
Mechanisms of Neuromodulation
NE Ach
NE
Ang II+
Mechanisms of Neuromodulation
Epi