NSF Award
8910042
Taste reception begins when stimulus chemicals, called tastants, interact with the exposed membrane of specialized receptor cells. Transduction is the term for the sequence of events that follow binding of a stimulus to the cellular receptor sites, triggering electrophysiological events in the cell that then lead to sending a nerve signal to the brain. In the vertebrates, this transduction occurs in special chemosensory cells in the taste buds. This project will examine how the interaction between the stimulus and the receptor membrane leads to the electrophysiological changes in the receptor cell. The cell membrane has channels that allow the flow of certain charged ions in and out. During stimulation, some of these channels open and close, with specific time courses and dependence on the electrical gradient across the membrane. Taste cells are found by the thousands all over the body of catfish, making them easy to isolate in large numbers for study, and these catfish taste cells have known classes of receptors for certain amino acids. This project will use physiological and pharmacological techniques on isolated catfish taste cells to characterize the ionic channels and currents in their membranes, and to determine how the binding of specific amino acids activate those channels. In addition, the role of particular proteins for activating internal compounds called second messenger molecules will be examined. Results from this novel model system will be very important to chemosensory science, and these studies are also likely to be helpful in studying synaptic mechanisms in neuroscience, in how receptor sites on nerve cells in the brain act during neurotransmission.
