Gustducin was discovered in 1992 when degenerate oligonucleotide primers were synthesized and mixed with a taste tissue cDNA library.

The DNA products were amplified by the polymerase chain reaction method, and eight positive clones were shown to encode the α subunits of G-proteins, (which interact with G-protein-coupled receptors).

[citation needed] Other G protein α-subunits have been identified in TRCs (e.g. Gαi-2, Gαi-3, Gα14, Gα15, Gαq, Gαs) with function that has not yet been determined.

α-Gustducin is selectively expressed in ~25–30% of TRCs [2] Due to its structural similarity to transducin, gustducin was predicted to activate a phosphodiesterase (PDE).

This experiment revealed transducin and gustducin were both expressed in taste tissue (1:25 ratio) and that both G proteins are capable of activating retinal PDE.

The 1992 research also investigated the role of gustducin in bitter taste reception by using "knock-out" mice lacking the gene for α-gustducin.

It was thought at the time that an alternative mechanism of bitter taste detection could be associated with the βγ subunit of gustducin.

This was not unexpected, as it was known that transducin was capable of sending signals within rod and cone cells at similar speeds.

It was later discovered that cAMP also causes an influx of cations during bitter and some sweet taste transduction, leading to the conclusion that it also acted as a second messenger to gustducin.

[citation needed] When bitter-stimulated T2R/TRB receptors activate gustducin heterotrimers, gustducin acts to mediate two responses in taste receptor cells: a decrease in cAMPs triggered by α-gustducin, and a rise in IP3(Inositol trisphosphate) and diacylglycerol (DAG) from βγ-gustducin.

[2] Although the following steps of the α-gustducin pathway are unconfirmed, it is suspected that decreased cAMPs may act on protein kinases which would regulate taste receptor cell ion channel activity.

This pathway starts with sucrose and other sugars activating Gs inside the cell through a membrane-bound GPCR.

It is believed that bitter taste receptors evolved as a mechanism to avoid ingesting poisonous and harmful substances.

If this is the case, one might expect different species to develop different bitter taste receptors based on dietary and geographical constraints.

Recent work by Enrique Rozengurt has shed some light on the presence of gustducin in the stomach and gastrointestinal tract.

Ronzegurt suggests that the presence of gustducin in epithelial cells in the stomach and gastrointestinal tract are indicative of another line of defense against ingested toxins.