Neurotransmitters

How are neurotransmitters classified?

chemical structure and function

Neurotransmitters have two functions

Effects and Actions

Effects are either

excitatory versus inhibitory

Excitatory results in...

depolarization

Inhibitory results in...

hyperpolarization

Actions are either

direct or indirect

Direct action

neurotransmitter binds directly and opens ion channels

Direct action is

fast-acting and through Ligand-gated ion channels

Indirect action

neurotransmitter acts through intracellular second messengers

Indirect action is

Slow-acting and cause metabolic changes

Neuromodulator

neurotransmitter released by neuron that does not directly cause EPSPs or IPSPs but instead affects the strength of synaptic transmission

Neuromodulators binds to

G protein-coupled receptor to activate G protein

Acetylcholine (ACh)

Released at NMJ and used by many ANS neurons and some CNS neurons

ACh classification

Direct action and indirect action, Excitatory at NMJ and

inhibitory in cardiac muscle

Dopamine

plays a major role in reward-motivated behavior, mood, and movement

Dopamine classification

excitatory and inhibitory,

Norepinephrine (NE)

mobilizes the brain and body for action

Epinephrine

also mobilizes the brain and body for action

Glutamate

most abundant excitatory neurotransmitter, Involved in long term potentiation thus learning and memory

Glutamate classification

Both direct and indirect action

GABA

principle inhibitory neuron

GABA Classification

Both direct and indirect action

Neural integration

neurons functioning together in groups

Neuronal pool

functional groups of neurons

Serial processing

input travels along one pathway to a specific destination in all-or-none manner

Example of serial processing

spinal reflex because it is a Rapid, automatic response to stimuli

Reflex Arcs

neural circuits that control reflexive behavior

Relax Arcs five components are

Receptor, afferent (sensory neuron), Integration center (interneuron), Efferent (motor neuron), Effector responds

Parallel processing

Input travels along several pathways

circuits

patterns of synaptic connections in neuronal pools