|a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.|
|a scrap or morsel of food left at a meal.|
neurotransmitter neu·ro·trans·mit·ter (n&oobreve;r'ō-trāns'mĭt-ər, -trānz'-, ny&oobreve;r'-)
Any of the various chemical substances, such as acetylcholine, that transmit nerve impulses across a synapse.
|neurotransmitter (nr'ō-trānz'mĭt-ər) Pronunciation Key
A chemical substance that is produced and secreted by a neuron and then diffuses across a synapse to cause excitation or inhibition of another neuron. Acetylcholine, norepinephrine, dopamine, and serotonin are examples of neurotransmitters.
Any one of a number of chemicals that are used to transmit nerve signals across a synapse. They are sprayed from the end of the “upstream” nerve cell and absorbed by receptors in the “downstream” cell.
Note: Drugs like Prozac and alcohol affect the emission and reception of neurotransmitters.