| Autor: |
Mateos-Hernandéz L; UMR BIPAR, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France., Defaye B; 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., Vancová M; Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice, Czech Republic.; Faculty of Science, University of South Bohemia, České Budejovice, Czech Republic., Hajdusek O; Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice, Czech Republic., Sima R; Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice, Czech Republic., Park Y; Department of Entomology, Kansas State University, 123 Waters Hall, Manhattan, KS, USA., Attoui H; UMR Virologie, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France., Šimo L; UMR BIPAR, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, Maisons-Alfort, France. ladislav.simo@vet-alfort.fr. |
| Abstrakt: |
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. |
