Immunohistochemical mapping of histamine, dopamine, and serotonin in the central nervous system of the copepod Calanus finmarchicus (Crustacea; Maxillopoda; Copepoda)

Abstract

Calanoid copepods constitute an important group of marine planktonic crustaceans that often dominate the metazoan biomass of the world's oceans. In proportion to their ecological importance, little is known about their nervous systems. We have used immunohistochemical techniques in a common North Atlantic calanoid to localize re-identifiable neurons that putatively contain the biogenic amines histamine, dopamine, and serotonin. We have found low numbers of such cells and cell groups (approximately 37 histamine pairs, 22 dopamine pairs, and 12 serotonin pairs) compared with those in previously described crustaceans. These cells are concentrated in the anterior part of the central nervous system, the majority for each amine being located in the three neuromeres that constitute the brain (protocerebrum, deutocerebrum, and tritocerebrum). Extensive histamine labeling occurs in several small compact protocerebral neuropils, three pairs of larger, more posterior, paired, dense neuropils, and one paired diffuse tritocerebral neuropil. The most concentrated neuropil showing dopamine labeling lies in the putative deutocerebrum, associated with heavily labeled commissural connections between the two sides of the brain. The most prominent serotonin neuropil is present in the anterior medial part of the brain. Tracts of immunoreactive fibers of all three amines are prominent in the cephalic region of the nervous system, but some projections into the most posterior thoracic regions have also been noted.

Histaminergic signaling in the central nervous system of Daphnia and a role for it in the control of phototactic behavior

“…That said, there appear to be exceptions to this rule, e.g. little if any histamine-like labeling is present in the photoreceptor system of the copepod Calanus finmarchicus (Hartline and Christie, 2010).…”

“…22939; Hudson, WI, USA), and has been used previously to map the distribution of histamine in the nervous systems of a number of other crustacean species (e.g. Mulloney and Hall, 1991;Le Feuvre et al, 2001;Pulver et al, 2003;Christie et al, 2004;Fu et al, 2005;Hartline and Christie, 2010). Visualization of the histamine antibody was accomplished using an Alexa-Fluor-488-conjugated donkey antirabbit IgG (catalog no.…”

“…Immunoprocessing was conducted on whole animal preparations using a procedure modified from Hartline and Christie (Hartline and Christie, 2010). In brief, animals were placed into 1.5ml microfuge tubes containing a solution of 4% 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDAC; catalog no.…”

“…Mulloney and Hall, 1991;Le Feuvre et al, 2001;Pulver et al, 2003;Christie et al, 2004;Fu et al, 2005;Hartline and Christie, 2010), ours is its first use in daphnids. Thus, to increase our confidence in the specificity of the histamine-like immunoreactivity described above, antibody adsorption controls were conducted (Table1).…”

“…Monastirioti, 1999;Nässel, 1999;Stuart, 1999;Homberg, 2002;Stuart et al, 2007), though exceptions to this rule appear to exist (e.g. Hartline and Christie, 2010). Here, a strategy combining immunohistochemistry and genome mining was used to identify and characterize the histaminergic systems in two daphnid species, Daphnia magna and Daphnia pulex.…”