Cholinergic input origins and current response properties in rat interstitial nucleus of Cajal neurons
- 1epartment of Neurophysiology, Nara Medical University, Kashihara, Japan
Abstract
The interstitial nucleus of Cajal (INC) and the prepositus hypoglossi nucleus (PHN) function as the neural integrators for vertical and horizontal gaze holding, respectively. Previous studies have suggested that cholinergic inputs from the mesopontine tegmentum modulate the function of the horizontal integrator; however, the modulation properties and origins of cholinergic inputs in the vertical integrator remain unclear. In this study, we investigated the cholinergic responses of INC neurons and the anatomical origin of the cholinergic inputs in rats. Whole-cell recordings in brainstem slices revealed that local application of acetylcholine (ACh) induced inward currents in INC neurons mediated by both nicotinic and muscarinic ACh receptors (nAChRs and mAChRs). Although current responses were predominantly mediated by nAChRs in PHN neurons, the participation of nAChRs and mAChRs differed depending on the INC neuron type. Retrograde tracing using an adeno-associated virus (AAV) in choline acetyltransferase (ChAT)-tdTomato transgenic rats demonstrated that the primary origin of cholinergic inputs to the INC was the caudal magnocellular region of the medial vestibular nucleus (MVeMC). Furthermore, the primary cholinergic inputs to the PHN originated from both the caudal MVeMC and the caudal PHN itself. These results indicate that the vertical neural integrator shares a common cholinergic source in the caudal MVN with the horizontal integrator, although the relative contributions of nAChRs and mAChRs are not necessarily shared between INC and PHN neurons. These findings suggest a potential role for cholinergic modulation in both vertical and horizontal gaze holding.
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BibTeX
@article{sugimura2026cholinergic,
title = {{Cholinergic input origins and current response properties in rat interstitial nucleus of Cajal neurons}},
author = {Taketoshi Sugimura and Yasuhiko Saito},
journal = {Frontiers in Cellular Neuroscience},
year = {2026},
month = oct,
doi = {10.3389/fncel.2026.1925102},
url = {https://doi.org/10.3389/fncel.2026.1925102},
note = {CC BY},
}
RIS
TY - JOUR
TI - Cholinergic input origins and current response properties in rat interstitial nucleus of Cajal neurons
AU - Taketoshi Sugimura
AU - Yasuhiko Saito
PY - 2026
DA - 2026/10/23
JO - Frontiers in Cellular Neuroscience
DO - 10.3389/fncel.2026.1925102
UR - https://doi.org/10.3389/fncel.2026.1925102
AB - The interstitial nucleus of Cajal (INC) and the prepositus hypoglossi nucleus (PHN) function as the neural integrators for vertical and horizontal gaze holding, respectively. Previous studies have suggested that cholinergic inputs from the mesopontine tegmentum modulate the function of the horizontal integrator; however, the modulation properties and origins of cholinergic inputs in the vertical integrator remain unclear. In this study, we investigated the cholinergic responses of INC neurons and the anatomical origin of the cholinergic inputs in rats. Whole-cell recordings in brainstem slices revealed that local application of acetylcholine (ACh) induced inward currents in INC neurons mediated by both nicotinic and muscarinic ACh receptors (nAChRs and mAChRs). Although current responses were predominantly mediated by nAChRs in PHN neurons, the participation of nAChRs and mAChRs differed depending on the INC neuron type. Retrograde tracing using an adeno-associated virus (AAV) in choline acetyltransferase (ChAT)-tdTomato transgenic rats demonstrated that the primary origin of cholinergic inputs to the INC was the caudal magnocellular region of the medial vestibular nucleus (MVeMC). Furthermore, the primary cholinergic inputs to the PHN originated from both the caudal MVeMC and the caudal PHN itself. These results indicate that the vertical neural integrator shares a common cholinergic source in the caudal MVN with the horizontal integrator, although the relative contributions of nAChRs and mAChRs are not necessarily shared between INC and PHN neurons. These findings suggest a potential role for cholinergic modulation in both vertical and horizontal gaze holding.
SN - 1662-5102
ER -