Mammalian Taste Cells Express Functional Olfactory Receptors

Area of Science:

• Neuroscience
• Chemosensation
• Sensory Systems Biology

Background:

• Mammalian taste and olfactory systems are traditionally viewed as independent, with distinct receptors and central processing.
• Flavor perception arises from the integration of taste and smell, historically believed to occur in the insular cortex.
• Recent findings indicate broader expression of chemosensory receptors in various tissues, challenging established models.

Purpose of the Study:

• To investigate the functional expression of olfactory receptors within mammalian taste papillae.
• To determine if taste cells possess physiologically active olfactory receptors.
• To explore the potential for peripheral integration of olfactory and gustatory information.

Main Methods:

• Utilized green fluorescent protein-expressing transgenic mice to visualize olfactory receptor expression in taste papillae.
• Employed immunocytochemistry and real-time quantitative polymerase chain reaction to detect olfactory signal transduction molecules and receptors in human taste cells.
• Assessed cellular responses to odorants in both mouse and human taste papilla cells, including the effects of adenylyl cyclase inhibition.

Main Results:

• Demonstrated the functional expression of olfactory receptors in mammalian taste papillae.
• Confirmed the presence of olfactory signal transduction molecules and olfactory receptors in cultured human fungiform taste papilla cells.
• Observed that both human and mouse taste papilla cells responded to odorants, with responses dependent on adenylyl cyclase activity.

Conclusions:

• Mammalian taste cells functionally express olfactory receptors, challenging the traditional view of separate sensory systems.
• The gustatory system may receive olfactory information at the peripheral level, within taste papillae.
• Initial integration of gustatory and olfactory information may occur at the level of taste receptor cells, prior to central processing.