detection of chemical stimulus involved in sensory perception of bitter taste

Definition

Target type: biologicalprocess

The series of events required for a bitter taste stimulus to be received and converted to a molecular signal. [GOC:go_curators]

The perception of bitter taste begins with the detection of bitter compounds by specialized taste receptor cells (TRCs) located in taste buds on the tongue. These TRCs express a family of G protein-coupled receptors (GPCRs) known as taste receptor type 2 (TAS2R) receptors. There are over 30 different TAS2R genes in humans, each encoding a receptor that can bind to a specific range of bitter compounds. When a bitter compound binds to a TAS2R receptor, it triggers a signaling cascade within the TRC. This cascade involves the activation of a G protein called gustducin, which in turn activates phospholipase C (PLC). PLC hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) to generate inositol trisphosphate (IP3) and diacylglycerol (DAG). IP3 binds to IP3 receptors on the endoplasmic reticulum, releasing calcium ions (Ca2+) into the cytoplasm of the TRC. This increase in intracellular Ca2+ concentration triggers the release of neurotransmitters, such as ATP and serotonin, from the TRC. These neurotransmitters diffuse to nearby sensory neurons that transmit the bitter taste signal to the brain. The signal travels through the cranial nerves (VII, IX, and X) to the brainstem, where it is relayed to the thalamus and then to the gustatory cortex in the cerebral cortex. The gustatory cortex is responsible for conscious perception of taste, including the perception of bitterness. The intensity of the perceived bitterness is determined by the concentration of the bitter compound, the specific TAS2R receptor involved, and the individual's genetic predisposition to bitterness sensitivity.'
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Proteins (27)

Compounds (176)