Neurotransmitter

Neurotransmitter

chemical used by a neuron to transmit an impulse across a synapse to another cell.

It a messenger of neurologic information from one cell to another.

Criteria for a neurotransmitter

1. Chemical synthesized presynaptically.

2. Electrical stimulation leads to the release of the chemical.

3. Chemical produces physiological effect

4. Terminate activity

Chemical classification of neurotransmitters

acetylcholine, biogenic amines, amino acids, neuropeptides

amino acid neurotransmitters

involved in fast synaptic transmission and are inhibitory and excitatory in action.

Examples include glutamate and aspartate

Amino acids as neurotransmitters

-glycine (inhibatory)

-GABA (inhibatory)

-glutamate (Excitatory)

-aspartate (Excitatory)

Amine neurotransmitters

A neurotransmitter based on modifications of a single amino acid nucleus.

involve slow synaptic transmission and are inhibitory and excitatory in action.

Examples include acetylcholine, serotonin, and dopamine.

amines as neurotransmitters

-Noradrenaline (Excitatory and Inhibitory)

-Adrenaline ( Excitatory and Inhibitory)

-Dopamine (Inhibitory)

-Serotonin (Inhibitory)

-Histamine (Excitatory)

Functional Classification of Neurotransmitters

excitatory or inhibitory

excitatory neurotransmitters

Cause depolarization of postsynaptic membranes

Promote action potentials.

acetylcholine

post synaptic potential

the change in the membrane potential of a neuron that has received stimulation from another neuron

inhibitory neurotransmitters

chemicals released from the terminal buttons of a neuron that inhibit the next neuron from firing; via inhibitory postsynaptic potentials

gamma amino butyric acid (GABA) and dopamine.firing via

inhibitory postsynaptic potentials

hyperpolarizations that move the membrane potential farther from threshold

Reuptake of neurotransmitters

the reabsorption of a neurotransmitter by a neurotransmitter transporter of a pre-synaptic neuron after it has performed its function of transmitting a neural impulse.

The reuptake process involves a specific carrier protein for each neurotransmitter.