Ectopic taste receptors in animal physiology: evolutionary conservation and functional diversification

Area of Science:

• Physiology
• Molecular Biology
• Evolutionary Biology

Background:

• Taste receptors are traditionally known for oral taste perception, crucial for food assessment and toxin avoidance.
• Recent discoveries reveal taste receptors in non-gustatory tissues like the gastrointestinal, cardiovascular, reproductive, and neural systems.
• These "ectopic" taste receptors play roles in hormone secretion, nutrient sensing, digestion, immunity, and motor control.

Purpose of the Study:

• To review the distribution and functions of extraoral taste receptors across various species, including mammals, teleosts, insects, and nematodes.
• To highlight commonalities and species-specific variations in ectopic taste receptor expression and function.
• To explore the implications of these receptors as potential pharmacological targets and their role in sensory evolution.

Main Methods:

• Literature review of recent research on taste receptor distribution and function in extraoral tissues.
• Comparative analysis of taste receptor roles across different animal phyla (mammals, teleosts, insects, nematodes).
• Synthesis of findings to establish a paradigm of taste receptors as polymodal sensors.

Main Results:

• Extraoral taste receptors are widely distributed across diverse non-gustatory tissues in multiple animal species.
• These receptors are involved in a broad range of physiological functions beyond taste, impacting homeostasis and adaptation.
• Significant variations exist in the specific roles and distributions of these receptors among different species.

Conclusions:

• Extraoral taste receptors are key players in integrating environmental signals with physiological homeostasis.
• They represent promising targets for therapeutic interventions in various diseases affecting multiple organ systems.
• The study of these receptors provides new insights into sensory system evolution and organismal adaptation.