Firing responses mediated via distinct nicotinic acetylcholine receptor subtypes in rat prepositus hypoglossi nuclei neurons

Abstract

We previously reported that cholinergic current responses mediated via nicotinic acetylcholine (ACh) receptors (nAChRs) in the prepositus hypoglossi nucleus (PHN), which participates in gaze control, can be classified into distinct types based on different kinetics and are mainly composed of α- and/or non-α-subtypes: fast (F)-, slow (S)-, and fast and slow (FS)-type currents. In this study, to clarify how each current type is related to neuronal activities, we investigated the relationship between the current types and the membrane properties and the firing responses that were induced by each current type. The proportion of the current types differed in neurons that exhibited different afterhyperpolarization (AHP) profiles and firing patterns, suggesting that PHN neurons show a preference for specific current types dependent on the membrane properties. In response to ACh, F-type neurons showed either one action potential (AP) or multiple APs with a short firing duration, and S-type neurons showed multiple APs with a long firing duration. The firing frequency of F-type neurons was significantly higher than that of S-type and FS-type neurons. An α-subtype-specific antagonist abolished the firing responses of F-type neurons and reduced the responses of FS-type neurons but had little effect on the responses of S-type neurons, which were reduced by a non-α-subtype-specific antagonist. These results suggest that the different properties of the current types and the distinct expression of the nAChR subtypes in PHN neurons with different membrane properties produce unique firing responses via the activation of nAChRs. NEW & NOTEWORTHY Prepositus hypoglossi nucleus (PHN) neurons show distinct nicotinic acetylcholine receptor (nAChR)-mediated current responses. The proportion of the current types differed in the neurons that exhibited different afterhyperpolarization profiles and firing patterns. The nAChR-mediated currents with different kinetics induced firing responses of the neurons that were distinct in the firing frequency and duration. These results suggest that the different properties of the current types in PHN neurons with different membrane properties produce unique firing responses via the activation of nAChRs.

Crosstalk between Bone and Nerves within Bone

“…[ 50,51 ] The receptors of ACh are well located in nervous system, suggesting that skeleton may regulate neural activities through modulating the neurotransmitter ACh. [ 194–198 ]…”

Different Activation Mechanisms of Excitatory Networks in the Rat Oculomotor Integrators for Vertical and Horizontal Gaze Holding

“…Cerebellar flocculus and paraflocculus inputs modulate the sustained activity of the neural integrators in a positive feedback manner (Zee et al, 1981;Leigh and Zee, 2015). In addition, the sustained depolarization is induced by cholinergic transmissions mediated via muscarinic (Navarro-López et al, 2004, 2005 and nicotinic receptors (Zhang et al, 2016(Zhang et al, , 2018 in PHN neurons. These modulations of neural activity, in addition to local excitatory networks, can produce the tonic activity sufficient for keeping eyes to an eccentric direction for a moment.…”