Transcript
Helps transfer information in the form of
nerve impulse
Pre-synaptic to postsynaptic
Neurohormones ?
Must be synthesized by a neuron
Stored in pre-synatic endings
Released at the synapse
Has specific receptors on Post-synaptic
membrane
Suitable termination of action
Group Ex’s
Acetylcholine Ach
Catecholamines NE, Epinephrine, Dopamine,
Serotonin, Histamine
Amino Acids Excitatory – Glutamate, Aspartate
Inhibitory – GABA , Glycine
Polypeptides ADH, oxytocin , endorphines ,
enkephalines , somatostatin ,
sunstance p , CRH, TRH..etc
Purines Adenosine , ATP
Gases NO , CO
Distribution
› All preganglionic neurons
› Post-ganglionic parasymapthetic
› Neuromuscular junctions
› Many parts of brain
› Amacrine cells in retina
Nicotinic – ligand gated ion channel
› Two subtypes
Muscarnic – G protein coupled
› Five subtypes (M1 to M5 )
Post ganglionic sympathetic nerves
Adrenal medulla (NE)
Properties Adrenalin & Nor-
Adrenalin
Dopamine
Receptors Alpha – 1, 2
Beta – 1, 2, 3
D1-5
Termination MAO
COMT
Same
Major inhibitory neurotransmitter in brain
and retina
Produced by decarboxylation
glutamate by glutamate decarboxylase
GABA a Brain Ligand gated ion
channel
GABA b Brain G protein coupled
GABA c Retina Ligand gated ion
channel
Inhibitory neurotransmitter
Site of action for
Anaesthetics
Sedatives ( benzodiazepins )
Alcohol
Predominantly inhibitory neurotransmitter
Glutamate
› major excitatory neurotransmitter
› Derived from kreb cycle
› Termination – taken up by astrocytes
› Excitotoxic
Aka 5 – Hydroxy tryptamine
Found in CNS , ENS , retina
In brain Raphe nucleus contain serotonin
Derived from trptophan
Receptors are 5HT 1-7 ( 7 types with subtypes )
Acts as a mood elevator
Hallucinogen
Also secreted by enterochromaffin cells ,platelets , basophills
Smooth muscle contraction ,
Neurotransmitter and hormone
Hypothalamus , limbic system
H1, H2, H3
Smooth muscle contraction
Secretion of HCL
Increased capillary permeability
Its one of the major tachykinin
(polypeptide11AA)
Found in many parts of brain , GIT,
Nerves
NK 1 , 2, 3 are receptors
Neurotransmitter for pain in dorsal horn
of spinal cord
in hypothalamus for endocrinal
modulation
Axon reflex
Peristalsis in gut
Along with dopamine in basal ganglia
Aka endothelium derived relaxing factor
(EDRF)
Blood vessels , brain
Derived from arginine by NO synthase
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