Meeting Abstract

P1-28  Thursday, Jan. 5 15:30 – 17:30  Variable Responses to Multiple Isoforms of a Neuropeptide, C-type Allatostatin (AST-C), by the Cardiac Neuromuscular System of the American Lobster, Homarus americanus PONG, S*; WALSH, P; ARMSTRONG, MK; CHRISTIE, AE; DICKINSON, PS; Bowdoin College; Bowdoin College; Bowdoin College; Univ. of Hawaii, Manoa; Bowdoin College spong@bowdoin.edu

Central pattern generator (CPG)-effector systems, which are responsible for producing rhythmic movements, are controlled by anatomically fixed neural networks, which are nonetheless able to produce multiple patterns of movement. An important mechanism allowing such variability is modulation by neurotransmitters and hormones, many of which are neuropeptides. The lobster heart, which is controlled by a nine neuron CPG, the cardiac ganglion, is modulated by C-type allatostatins (AST-C), two of which [pQIRYHQCYFNPISCF, now AST-C I, and SYWKQCAFNAVSCFamide, now AST-C II] were previously known; both have previously been shown to modulate the lobster heart. Using transcriptomes generated from nervous system tissues, we identified a third isoform of AST-C, GNGDGRLYWRCYFNAVSCF, or AST-C III, in the lobster. All three AST-C isoforms consistently lead to decreases in contraction frequency when perfused through an isolated lobster heart; in contrast, all can elicit variable responses in contraction amplitude, with amplitude increasing in some lobsters and decreasing in others. Interestingly, the responses to AST-C I and AST-C III are more similar to one another than to AST-C II in any given lobster. We hypothesize that the differences in expression of AST-C receptors among individuals may cause these varying responses. Supported by: NSF (IOS-1353023, IOS-1354567), NIH (8P20GM103423-12), Cades Foundation, Doherty Foundation gift to Bowdoin College