Meeting Abstract
Gill lateral cells of Crassostrea virginica are innervated by serotonin and dopamine. The motor aspects have been well studied, but not the sensory side. Histamine (HIS) is a neurotransmitter and ligand for sensory receptors in invertebrates, but studies in bivalves are rare. We found HIS in ganglia and tissues of C. virginica and C. virginica can alter cilia beating in response to applying chemical including HIS to mantle. HIS does not alter cilia beating when applied to gill. We hypothesize HIS receptors are present in mantle and we can confirm the receptor type using Western Blot. We used HIS H1, H2 and H3 receptor agonists and antagonist at the mantle rim. Dose responses were conducted and cilia beating observed with stroboscopic microscopy. Results show H2 agonists and antagonists had the strongest effects on beating. For Western Blot, mantle body and mantle rim lysates were prepared by polytron disruption in NP-40 detergent buffer containing protease inhibitor, followed by centrifugation to obtain supernatant with solubilized mantle body and mantle rim membrane proteins. Up to 30 µg of protein was subjected to SDS-PAGE with 10% acrylamide gels and electroblotted onto nitrocellulose. H2 receptor immunoreactivity was revealed after incubation with primary antibodies followed by HRP-conjugated secondary antibody and resolved via colormetric development using CN/DAB substrate kit. Western Blot showed a strong band at 70 kD corresponding to HIS H2 receptors in both mantle body and mantle rim. The study shows mantle body and mantle rim of C. virginica contain HIS H2 receptors and further demonstrates a distinct physiological role of HIS in the sensory-motor integration of gill lateral cell cilia activity.
