Unconventional Neurotransmitters in the Carotid Body

The mammalian carotid body expresses a variety of neurochemicals and their receptors (see Tables 1 and 2). The transmitters expressed in the carotid body can be classified into two major categories conventional and imconventional. The conventional class of neurotransmitters includes those that are stored in vesicles and exert their effect via activation of specific receptors. Examples of this class include catecholamines, acetylcholine, and neuropeptides, whereas gas molecules like nitric oxide (NO) and carbon monoxide (CO) form the class of unconventional neurotransmitters. These molecules are generated spontaneously by way of enzymatic reactions and mediate their biological actions by either activation 

Dopamine (10,20,91) Rat, cat, human, rabbit Type I cells, nerve fibers 

Norepinephrine (10,18) Rat, cat, rabbit Type 1 cells and nerve fibers 

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