Neurotransmitters, Neuromodulators, and their receptors The following slides provides a summary of the major classes of neurotransmitters and the names of the receptors that have been identified. The drugs listed in these slides are drugs that affect neuronal transmission by attaching to the post and pre-synaptic receptors. Other drugs (not listed in these slides) affect neuronal functioning by altering some other function of a neuron.

Neurotransmitters (NT) & Neuromodulators (NM) 1. Acetylcholine (NT) 2. Monoamines (NT; NM) 3. Amino Acids (NT; NM) 4. Peptides (NT; NM) 5. Lipid-like substances (NT) 6. Nucleosides (NM) 7. Soluble gases A. Catecholamines B. Indolamines Dopamine norepinephrne epineprine Serotonin Glutamate GABA Glycine Endorphins, enkephalins Anandamide, leptin adenosine Nitric Oxide, Carbon Monoxide (atypical)

Types of drugs base on their effects on receptors Agonist - a drug that binds with and activates a postsynaptic receptor. Antagonist - a drug that binds with a postsynaptic receptor and does not activate it; may block the natural transmitter from binding with the receptor Different subtypes of Agonists and antagonists are described on the next slide

( also called Receptor Blocker) (A better but never used term is indirect antagonist)

Receptor subtypes Receptors belonging to one class of neurotransmitters (e.g. Dopamine) may respond differently to various drugs. When this is the case the receptors are divided into subclasses. E.g. There are several Dopamine receptors, each responding to dopamine but differently to different drugs. These receptors are called D1, D2, D3, D4, and D5 receptors