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Mateos-Hernandéz L, Defaye B, Vancová M, Hajdusek O, Sima R, Park Y, Attoui H, Šimo L. Cholinergic axons regulate type I acini in salivary glands of Ixodes ricinus and Ixodes scapularis ticks. Sci Rep 2020; 10:16054. [PMID: 32994503 PMCID: PMC7524744 DOI: 10.1038/s41598-020-73077-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 09/10/2020] [Indexed: 12/03/2022] Open
Abstract
Regulatory factors controlling tick salivary glands (SGs) are direct upstream neural signaling pathways arising from the tick's central nervous system. Here we investigated the cholinergic signaling pathway in the SG of two hard tick species. We reconstructed the organization of the cholinergic gene locus, and then used in situ hybridization to localize mRNA encoding choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) in specific neural cells in the Ixodes synganglion. Immunohistochemical staining revealed that cholinergic axonal projections exclusively reached type I acini in the SG of both Ixodes species. In type I acini, the rich network of cholinergic axons terminate within the basolateral infoldings of the lamellate cells. We also characterized two types (A and B) of muscarinic acetylcholine receptors (mAChRs), which were expressed in Ixodes SG. We pharmacologically assessed mAChR-A to monitor intracellular calcium mobilization upon receptor activation. In vivo injection of vesamicol-a VAChT blocker-at the cholinergic synapse, suppressed forced water uptake by desiccated ticks, while injection of atropine, an mAChR-A antagonist, did not show any effect on water volume uptake. This study has uncovered a novel neurotransmitter signaling pathway in Ixodes SG, and suggests its role in water uptake by type I acini in desiccated ticks.
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Affiliation(s)
- Lourdes Mateos-Hernandéz
- UMR BIPAR, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France
| | - Baptiste Defaye
- UMR BIPAR, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France
- Faculté de Pharmacie, Université de Limoges, Limoges, France
- UMR SPE 6134 CNRS, Université de Corte Pascal Paoli, Corse, France
| | - Marie Vancová
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budejovice, Czech Republic
| | - Ondrej Hajdusek
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice, Czech Republic
| | - Radek Sima
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice, Czech Republic
| | - Yoonseong Park
- Department of Entomology, Kansas State University, 123 Waters Hall, Manhattan, KS, USA
| | - Houssam Attoui
- UMR Virologie, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France
| | - Ladislav Šimo
- UMR BIPAR, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France.
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