title: Nicotinic acetylcholine receptor-mediated responses in medial vestibular and prepositus hypoglossi nuclei neurons showing distinct neurotransmitter phenotypes.
abstract: Cholinergic transmission in both the medial vestibular nucleus (MVN) and prepositus hypoglossi nucleus (PHN) plays an important role in horizontal eye movements. We previously demonstrated that the current responses mediated via nicotinic acetylcholine receptors (nAChRs) were larger than those mediated via muscarinic acetylcholine receptors (mAChRs) in cholinergic MVN and PHN neurons that project to the cerebellum. In this study, to clarify the predominant nAChR responses and the expression patterns of nAChRs in MVN and PHN neurons that exhibit distinct neurotransmitter phenotypes, we identified cholinergic, inhibitory, and glutamatergic neurons using specific transgenic rats and investigated current responses to the application of acetylcholine (ACh) using whole cell recordings in brain stem slices. ACh application induced larger nAChR-mediated currents than mAChR-mediated currents in every neuronal phenotype. In the presence of an mAChR antagonist, we found three types of nAChR-mediated currents that exhibited different rise and decay times and designated these as fast (F)-, slow (S)-, and fast and slow (FS)-type currents. F-type currents were the predominant response in inhibitory MVN neurons, whereas S-type currents were observed in the majority of glutamatergic MVN and PHN neurons. No dominant response type was observed in cholinergic neurons. Pharmacological analyses revealed that the F-, S-, and FS-type currents were mainly mediated by α7, non-α7, and both α7 and non-α7 nAChRs, respectively. These findings suggest that cholinergic responses in the major neuronal populations of the MVN and PHN are predominantly mediated by nAChRs and that the expression of α7 and non-α7 nAChRs differ among the neuronal phenotypes.
authors.affiliation: Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan; Department of Physiology, Dalian Medical University, Dalian, China;
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan; Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), Chiyoda-ku, Tokyo, Japan; and.
authors.forename: Yuchio
authors.initials: Y
authors.lastname: Yanagawa
authors.affiliation: Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan; Department of Neurophysiology, Nara Medical University, Kashihara, Nara, Japan syasu@naramed-u.ac.jp.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Saito
mesh_terms: D000818:Animals; D005260:Female; D007002:Hypoglossal Nerve / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D018722:Nicotinic Agonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D010641:Phenotype; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011978:Receptors, Nicotinic / Q000235:genetics / Q000378:metabolism*; D009435:Synaptic Transmission; D014726:Vestibular Nuclei / Q000166:cytology / Q000378:metabolism* / Q000502:physiology
chemical_list: D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D021122:Protein Subunits; D011978:Receptors, Nicotinic
keywords: cholinergic; dihydro-β-erythroidine; methyllycaconitine; transgenic rat; whole cell recording