Gasotransmitters: New Frontiers in Neuroscience BY AUDREY HERRALD '23 Cover Image: A threedimensional representation of the nitric oxygen synthase (NOS) protein, a critical player in the synthesis of nitric oxide (NO), the first identified gasotransmitter Created by Jawahar Swaminathan and MSD staff at the European Bioinformatics Institute, from Wikimedia Commons
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Introduction The average adult brain is comprised of about 120 billion neurons (Herculano-Houzel, 2001). Communication between the neurons in this vast network is important for cognition, behavior, and even physiological function; in short, neural signaling is a critical element of life (Neural Signaling, 2001). This signaling generally occurs through one or some combination of two mechanisms: electrical transmission and chemical transmission. The “all-or-nothing” action potential is a relatively well-known example of electrical transmission, and endogenous signaling molecules called neurotransmitters are equally familiar. However, a lesser-known but profoundly important class of molecules regulates our cardiovascular, nervous, gastrointestinal, excretory, and immune systems—in addition to many cellular functions, including apoptosis, proliferation, inflammation, cellular metabolism, oxygen sensing, and gene
transcription (Handbook of Hormones, 2016). Their name? Gasotransmitters. The phrase “gasotransmitter” was first coined in 2002 when a team of researchers identified hydrogen sulfide (H2S) as the third gaseous signaling molecule of its kind (Wang et al., 2002). The rotten-egg smelling molecule joined nitric oxide (NO) and carbon monoxide (CO) in the group of molecules referred to as gasotransmitters. Since then, advancements in understanding of the cellular signaling process have led to the proposed identification of other gasotransmitters, like ammonia (NH3). These molecules dictate a wide variety of physiological processes, and the mechanisms of effect are accordingly varied. Section 1 of this paper will address the various functional mechanisms of the three broadly accepted gasotransmitters, in addition to providing a clearer profile of what, exactly, these gasotransmitters look like and how they mediate neural connectivity. Section DARTMOUTH UNDERGRADUATE JOURNAL OF SCIENCE
