Leucokinin neuropeptide in the tick Ixodes ricinus: Neurohaemal release site, salivary gland innervation, and receptor distribution
Abstract
Leucokinin (LK) has been functionally characterised in ticks, but its anatomical organisation remains poorly understood. Here, we investigate the anatomical and molecular organisation of LK and its receptor (LKR) in the tick Ixodes ricinus using molecular and anatomical approaches. We functionally identified the I. ricinus LKR and confirmed its activation by LK. Quantitative PCR revealed lkr transcripts across life stages and in peripheral tissues, including salivary glands. Within the synganglion, LK was localised to a defined population of medial protocerebral neurosecretory neurons by immunohistochemistry and confirmed by in situ hybridisation. Their axons project to the dorsolateral perineurium of the synganglion, suggesting a neurohaemal release site supported by ultrastructural evidence. LKR immunoreactivity was detected in a limited subset of neuronal somata within the synganglion. In peripheral tissues, LK-immunoreactive axons innervate salivary glands, mainly type II acini and occasionally type III acini. LKR immunoreactivity was detected in the corresponding acinar cells. This spatial organisation of axonal projections and receptor localisation suggests a role for LK in the regulation of acinar activity. Together, these findings refine the anatomical organisation of LK in I. ricinus and provide a framework for future functional studies.
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BibTeX
@article{abuindenis2026leucokinin,
title = {{Leucokinin neuropeptide in the tick Ixodes ricinus: Neurohaemal release site, salivary gland innervation, and receptor distribution}},
author = {Lianet Abuin-Denis and Lívia Šofranková and Cáinà Nìng and Emyl Stransky and Sabine Rakotobe and Mirko Slovák and Ondřej Hajdušek and Jan Perner and Martina Tesařová and Marie Vancová and Ladislav Šimo},
journal = {Ticks and Tick-borne Diseases},
year = {2026},
month = jul,
doi = {10.1016/j.ttbdis.2026.102683},
url = {https://hal.inrae.fr/hal-05631013v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Leucokinin neuropeptide in the tick Ixodes ricinus: Neurohaemal release site, salivary gland innervation, and receptor distribution
AU - Lianet Abuin-Denis
AU - Lívia Šofranková
AU - Cáinà Nìng
AU - Emyl Stransky
AU - Sabine Rakotobe
AU - Mirko Slovák
AU - Ondřej Hajdušek
AU - Jan Perner
AU - Martina Tesařová
AU - Marie Vancová
AU - Ladislav Šimo
PY - 2026
DA - 2026/07/24
JO - Ticks and Tick-borne Diseases
DO - 10.1016/j.ttbdis.2026.102683
UR - https://hal.inrae.fr/hal-05631013v1
AB - Leucokinin (LK) has been functionally characterised in ticks, but its anatomical organisation remains poorly understood. Here, we investigate the anatomical and molecular organisation of LK and its receptor (LKR) in the tick Ixodes ricinus using molecular and anatomical approaches. We functionally identified the I. ricinus LKR and confirmed its activation by LK. Quantitative PCR revealed lkr transcripts across life stages and in peripheral tissues, including salivary glands. Within the synganglion, LK was localised to a defined population of medial protocerebral neurosecretory neurons by immunohistochemistry and confirmed by in situ hybridisation. Their axons project to the dorsolateral perineurium of the synganglion, suggesting a neurohaemal release site supported by ultrastructural evidence. LKR immunoreactivity was detected in a limited subset of neuronal somata within the synganglion. In peripheral tissues, LK-immunoreactive axons innervate salivary glands, mainly type II acini and occasionally type III acini. LKR immunoreactivity was detected in the corresponding acinar cells. This spatial organisation of axonal projections and receptor localisation suggests a role for LK in the regulation of acinar activity. Together, these findings refine the anatomical organisation of LK in I. ricinus and provide a framework for future functional studies.
SN - 1877-959X
SN - 1877-9603
ER -