Tyrosine hydroxylase messenger RNA corroborates protein localization in the nervous system of the pond snail, Lymnaea stagnalis

Catecholaminergic neurons are abundant in molluscs and are involved in a variety of behaviors such as feeding, respiration, learning, and locomotion. However, previous identification of these neurons has relied almost exclusively on immunohistochemistry using antibodies, which have not been fully validated for use in molluscs. We employed tissue-specific quantitative PCR in adults of Lymnaea stagnalis (a pulmonate gastropod) and whole-mount in situ hybridization in larvae to both quantify and visualize messenger RNA of the catecholamine synthesis enzyme, tyrosine hydroxylase (TH). TH messenger RNA was found to localize primarily in the foot and the central nervous system, with smaller quantities present in the cephalic sensory organs. Additionally, we performed western blots that validated a popular antibody used as a marker for catecholaminergic neurons in molluscs. Taken together, these data indicate that TH messenger RNA is present in the central and peripheral nervous system of L. stagnalis and support the specificity of past immunohistochemical labeling of the TH protein. These findings have potentially broad implications, given the wide range of biological processes that have been studied in L. stagnalis.