Table 2.
Biosensors used to study taste in the brain. Taste bud are innervated by sensory neurons that convey the information to the CNS. This has been studied with live imaging microscopy in vivo with mostly genetically encoded Ca2+ sensors. Abbreviations: NTS: solitary tract, PBN: parabranchial nucleus, GC: gustatory cortex, genic.gangl: geniculate ganglion, Tr.: transgenic.
| Region | Species | Transgenic Model | Tracing | Sensor | Detect | Stimuli | Microscopy Technique | Source |
|---|---|---|---|---|---|---|---|---|
| Genic.gangl. | Mouse | Tr. mouse 5HT3A-GFP |
Fura-2/Fluoro-Gold | Ca2+ | 5HT | Confocal | [38] | |
| Tr. mouse Pirt-GCamMP3 |
GCaMP3 | Sweet, bitter, umami, salt, sour | [205] | |||||
| Tr. mouse Thy1-GCaMP3 |
AVV-GCaMP3 (retrograde/NTS) |
Two-photon | [201] | |||||
| NTS | Tr. mouse T2R5, tWGA-DsRed |
Zif268 | Sweet, bitter | Conventional | [206] | |||
| PBN | Mouse SatB2-Cre Vglut2-ihres-Cre |
AAV1-Cre-GCaMP6s | AAV8-Cre-synaptophysin-mCherry AAV5-DIO-ChR2-EYFPin PBN |
GCaMP6s | Ca2+ c-fos |
Bitter | Miniaturized | [208] |
| Brain stem | Zebra fish | Tr. fish Elav3-GCaMP5 |
GCaMP5 | Ca2+ | Sweet, bitter, umami, sour | Two-photon | [213] | |
| GC | Mouse | AVV1-GCaMP6s | AVV1-mCherry/microruby dextran (anterograde-thalamus) |
GCaMP6s | Sweet, bitter, salt, sour | [192] | ||
| AAV2/1-GCaMP6s | CAV2-Cre in hCAR x dTomato mice (retrograde-amygdala) |
Bitter | [207] | |||||
| Mouse T2R5/T1R2 knockout |
AVV2-GFP (anterograde-thalamus) |
GCaMP6s OGB-AM + sulforhodamine 101 |
Sweet, bitter, umami, salt | [202] |