On the Brain of a Crustacean: A Morphological Analysis of CaMKII Expression and Its Relation to Sensory and Motor Pathways

Abstract

Calcium/calmodulin kinase II (CaMKII) is a Ca2+-activated enzyme that is abundant in vertebrate and invertebrate brains. However, its characterization is poorly addressed in the nervous system of crustaceans, and, to our knowledge, no studies have determined the microanatomical location of CaMKII in a crustacean species. In this study, we found labeling of CaMKII in the eyestalk and brain of the prawn Macrobrachium acanthurus, by means of immunohistochemistry and Western blotting. Antibodies against neuron (ß tubulin III), glutamate receptor (GluA1), and FMRFamide were used in order to further characterize the CaMKII-labeled cells in the brain. In the eyestalk, strong labeling with CaMKII was observed in the photoreceptors. These cells, especially in the rhabdom, were also reactive to anti-ß tubulin III, whereas the pigment cells were labeled with anti-CaMKII. GluA1 co-located with CaMKII in the photoreceptors. Also, CaMKII appeared in the same sites as FMRFamide in the deutocerebrum, including the olfactory lobe, and in the tritocerebrum, specifically in the antennular neuropil, indicating that the synaptic areas in these regions may be related to sensory-motor processing. In the brain, the identification of cells and regions that express CaMKII contributes to the understanding of the processing of neural connections and the modulating role of CaMKII in decapod crustaceans.

Comparative neuroanatomical distribution and expression levels of neuropeptide F in the central nervous system of the female freshwater prawn, Macrobrachium rosenbergii, during the ovarian cycle

“…Intense MrNPF-ir was detected in the glomeruli of the ON, in the MAN, and in small-and medium-sized neurons of cluster 9/11 and small neurons of cluster 10, whose numbers were high in mid-to lateovarian stages and slightly decreased at the mature stages. This pattern of MrNPF-ir distribution is generally similar to that reported in male M. rosenbergii (Thongrod et al, 2017), and in RFamide-ir in P. argus (Schmidt & Ache, 1997), M. acanthurus (Ammar et al, 2013), L. vannamei (Meth et al, 2017), C. clypeatus (Harzsch & Hansson, 2008;Polanska et al, 2012), C. maenas, and Pagurus bernhardus (Krieger et al, 2012).…”

“…The apices of glomeruli pointing inwards of the ON are the locations of synaptic contact between the local interneurons, projection neurons, and receptor neurons (Beltz et al, 2003;Schmidt & Mellon 2011;Sullivan & Beltz, 2004). The small-sized neurons (less than 15 μm in diameter) may act as interneurons (local olfactory interneurons, e.g., cluster 9), which coordinate connections of the olfactory pathways (Ammar et al, 2013;Sandeman et al, 2014;Schachtner et al, 2005;Tautz & Müller-Tautz, 1983). The cells of cluster 10 are projection neurons that constitute the output fibers of the olfactory and accessory lobes (Harzsch et al, 2012;Sullivan & Beltz, 2004), while the neurons of cluster 11 contain olfactory interneurons that respond to substances when these are administered to the antennule (Harzsch et al, 2012;Mellon & Alones, 1997;Sandeman et al, 2014).…”