Meeting Abstract

P3.7  Saturday, Jan. 5  Characterization of Carbohydrates that Depress Crayfish Cardiac Rhythms following Chemoreception PAN, V.*; SILVERTHORN, D.U.; University of Texas – Austin; University of Texas – Austin silverthorn@mail.utexas.edu

It has previously been observed that freshwater crayfish demonstrate a depression in cardiac rhythm upon detection of certain carbohydrates. The location and structure of the molecular receptor is uncertain, as is the adaptive significance of this modification in cardiac activity. It is likely that carbohydrate chemoreception is associated with feeding, as the magnitude of the response varied with feeding state. This experiment focused on characterizing the structural configuration common to active compounds that elicit this response. To do so, metal electrodes serving as ECG leads were implanted in the dorsal carapace of anesthetized crayfish. After a 48-hour recovery period, the crayfish were restrained and covered to minimize stimuli that would otherwise affect their cardiac activity. For each compound tested, 3 mL of 0.25M solution were added to the water next to the crayfish�s gill intake area. The ECG was monitored for at least 30 seconds before and after the addition of the sugar for changes associated with the addition of the carbohydrate. It has been found that carbohydrates with a pyranose ring and an available hydroxyl at C1, such as glucose, maltose, and xylose, are active compounds that stimulate the depression in cardiac activity. The configuration at the other carbons appears to be less critical in this response. Further research will utilize more carbohydrates, as well as amino acids and artificial sweeteners, to characterize the active compounds in further detail. This would ultimately contribute to a better understanding of the carbohydrate receptor associated with the depression in cardiac rhythm.