Evidence for the cholinergic markers ChAT and vAChT in sensory cells of the developing antennal nervous system of the de
- PDF / 1,461,257 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 56 Downloads / 209 Views
ORIGINAL ARTICLE
Evidence for the cholinergic markers ChAT and vAChT in sensory cells of the developing antennal nervous system of the desert locust Schistocerca gregaria Erica Ehrhardt1,2 · George Boyan1 Received: 28 June 2020 / Accepted: 15 October 2020 © The Author(s) 2020
Abstract Sensory and motor systems in insects with hemimetabolous development must be ready to mediate adaptive behavior directly on hatching from the egg. For the desert locust S. gregaria, cholinergic transmission from antennal sensillae to olfactory or mechanosensory centers in the brain requires that choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (vAChT) already be present in sensory cells in the first instar. In this study, we used immunolabeling to demonstrate that ChAT and vAChT are both expressed in sensory cells from identifiable sensilla types in the immature antennal nervous system. We observed ChAT expression in dendrites, neurites and somata of putative basiconic-type sensillae at the first instar stage. We also detected vAChT in the sensory axons of these sensillae in a major antennal nerve tract. We then examined whether evidence for cholinergic transmission is present during embryogenesis. Immunolabeling confirms that vAChT is expressed in somata typical of campaniform sensillae, as well as in small sensory cell clusters typically associated with either a large basiconic or coeloconic sensilla, at 99% of embryogenesis. The vAChT is also expressed in the somata of these sensilla types in multiple antennal regions at 90% of embryogenesis, but not at earlier (70%) embryonic stages. Neuromodulators are known to appear late in embryogenesis in neurons of the locust central complex, and the cholinergic system of the antenna may also only reach maturity shortly before hatching. Keywords Locust · Antenna · Development · Sensory cells · ChAT · vAChT
Introduction Acetylcholine is a ubiquitous neuromodulator with extensive roles in insect physiology and behavior (Heinrich et al. 1997; Kunst et al. 2011; Boppana et al. 2017; Deshpande et al. 2020; Showell et al. 2020). In the fly, for example, most chemosensory, olfactory, chordotonal, and auditory primary sensory neurons are cholinergic (Salvaterra and Erica Ehrhardt and George Boyan have contributed equally to this work. * George Boyan [email protected] 1
Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität München, Grosshadernerstrasse 2, 82152 Planegg, Martinsried, Germany
Institute of Zoology, Universität Köln, Zülpicher Str 47b, 50674 Cologne, Germany
2
Kitamoto 2001). In the locust, components of cholinergic transmission including acetylcholinesterase, choline acetyltransferase, the high affinity choline transport system, and acetylcholine receptors are expressed throughout the adult CNS (see Homberg 2002 for review). The central projections of antennal afferents in the brain are also cholinergic (Knipper et al. 1989; Rind and Leitinger 2000), although the sensilla types involved remain unidentified. In ins
Data Loading...
