Meeting Abstract
P3.188 Monday, Jan. 6 15:30 Identification of a 5-HT7 receptor in the ABRM of the mussel Mytilus edulis MCPHERSON, D.*; COLLISSON, N.; IUPPA, A.; KATZ, R.; LOVETT, J.; SUNY Geneseo; SUNY Geneseo; SUNY Geneseo; SUNY Geneseo; SUNY Geneseo mcpherso@geneseo.edu
The anterior byssus retractor muscle (ABRM) of the blue mussel, Mytilus edulis, has been studied intensively for its ability to maintain prolonged contraction in a catch state with minimal expenditure of energy. Relaxation from the catch state can be induced by serotonin (5-HT). Serotonin acts in this system to stimulate adenylyl cyclase, increasing the synthesis of cyclic adenosine monophosphate (cAMP), which in turn activates protein kinase A (PKA). Phosphorylation of the giant protein twitchin by PKA then leads to muscle relaxation. Despite the high level of detail in our current understanding of the ABRM system, nothing is yet known regarding the identity of the receptor that mediates the effects of serotonin. We have isolated and cloned a portion of a gene in Mytilus edulis which encodes a 5-HT receptor, and we have evidence that the mRNA for it is expressed in the ABRM. Analysis of the predicted amino acid sequence for the receptor indicates that it belongs to the 5-HT7 family, and the activation of 5-HT7 receptors is known to stimulate adenylyl cyclase. This receptor is therefore a good candidate to mediate the catch-relaxing effect of 5-HT in the ABRM.
