Nerve Conduction: Between Neurons

After the action potential reaches the terminal buttons, chemicals called neurotransmitters are released into the synapse. The synapse is the narrow space between the terminal buttons of the sending neuron and the dendrites of the receiving neuron. In fact, special terminology relative to the synapse identifies the sending neuron as the presynaptic neuron and the receiving neuron as the postsynaptic neuron.

Neurotransmitters communicate across the synapse in two ways. One way is to continue to propagate the action potential. When neurotransmitters continue the message they deliver an EPSP or excitatory postsynaptic potential and the information is transmitted. Neurotransmitters can also deliver an IPSP or inhibitory postsynaptic potential which causes transmission to cease. Typically, different neurotransmitters are responsible for EPSPs and IPSPs. (See the lecture--Integration: All-or-none and Summation for more information on the role of excitation and inhibition.)

URLs

Biochemistry of Neurotransmitters--tutorial, interm., long, links

Part of larger page on medical biochemistry (link on page), this site explains the action of neurotransmitters. Topics are synaptic transmission, neuromuscular transmission, neurotransmitter receptors, acetylcholine, cholinergic agonists and antagonists, catecholamines, serotonin, and GABA. http://web.indstate.edu/thcme/mwking/nerves.html

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