chemoreceptive

Chemo receptive describes the property of detecting chemical stimuli through specialized receptors, known as chemoreceptors. In biology, chemoreception encompasses the detection of chemical signals in the environment (external chemoreception) and in body fluids (internal chemoreception). Cells or tissues described as chemoreceptive contain receptors that bind specific molecules and convert binding into electrical or chemical signals that guide behavior or physiology.

In animals, chemoreception includes gustation (taste) and olfaction (smell). Taste receptors on the tongue and oral cavity respond to dissolved substances, while olfactory receptor neurons in the nasal cavity detect volatile compounds. Beyond these senses, peripheral chemoreceptors such as the carotid bodies monitor arterial blood levels of oxygen, carbon dioxide, and pH, helping regulate respiration. Central chemoreceptors located in the brainstem respond to CO2-induced changes in pH in cerebrospinal fluid.

Molecular basis: The chemoreceptors are diverse. In olfaction and many taste cells, receptors are G-protein-coupled receptors that activate second messenger pathways. Some taste cells use ion channels; others rely on GPCR signaling. The olfactory system expresses a large family of odorant receptors, each responsive to certain chemical structures.

Significance and applications: Chemoceptive systems guide feeding, mating, avoidance of toxins, and homeostatic regulation of breathing. Deficits in chemoreception, such as anosmia or ageusia, are clinically important and can arise from disease or injury. Research on chemoreceptors informs sensory biology, neurophysiology, and the development of biosensors and artificial chemosensory devices.