Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5737635 | Neuroscience | 2017 | 56 Pages |
Abstract
Phox2b encodes a paired-like homeodomain-containing transcription factor essential for development of the autonomic nervous system. Phox2b-expressing (Phox2b+) neurons are present in the reticular formation dorsal to the trigeminal motor nucleus (RdV) as well as the nucleus of the solitary tract and parafacial respiratory group. However, the nature of Phox2b+ RdV neurons is still unclear. We investigated the physiological and morphological properties of Phox2b+ RdV neurons using postnatal day 2-7 transgenic rats expressing yellow fluorescent protein under the control of Phox2b. Almost all of Phox2b+ RdV neurons were glutamatergic, whereas Phox2b-negative (Phox2bâ) RdV neurons consisted of a few glutamatergic, many GABAergic, and many glycinergic neurons. The majority (48/56) of Phox2b+ neurons showed low-frequency firing (LF), while most of Phox2bâ neurons (35/42) exhibited high-frequency firing (HF) in response to intracellularly injected currents. All, but one, Phox2b+ neurons (55/56) did not fire spontaneously, whereas three-fourths of the Phox2bâ neurons (31/42) were spontaneously active. K+ channel and persistent Na+ current blockers affected the firing of LF and HF neurons. The majority of Phox2b+ (35/46) and half of the Phox2bâ neurons (19/40) did not respond to stimulations of the mesencephalic trigeminal nucleus, the trigeminal tract, and the principal sensory trigeminal nucleus. Biocytin labeling revealed that about half of the Phox2b+ (5/12) and Phox2bâ RdV neurons (5/10) send their axons to the trigeminal motor nucleus. These results suggest that Phox2b+ RdV neurons have distinct neurotransmitter phenotypes and firing properties from Phox2bâ RdV neurons and might play important roles in feeding-related functions including suckling and possibly mastication.
Keywords
CCHSpostsynaptic currentsGLYT2pFRGVGLUT1VGLUT2GAD65INaPmedialRTNEYFPglutamic acid decarboxylase 65PRVPHOX2BCcellGmaxPSCsPBNRDVMOVSTIMstimulating electrodeVRestsupratrigeminal nucleusGad67recSCPDAPITBS4-APglutamic acid decarboxylase 67eGFPAMPDAB3,3′-diaminobenzidine tetrahydrochloride4-aminopyridine4,6-diamidino-2-phenylindoleKolliker–Fuse nucleusBACsuperior cerebellar peduncleMEDphosphate bufferafterhyperpolarizationTris-buffered salineMasticationvesicular glutamate transporter 2vesicular glutamate transporter 1cell capacitanceAmplitudeDORpostnatal dayCongenital central hypoventilation syndromeSucklingdorsal AHPinput resistancepremotor neuronConductanceparabrachial nucleusPrincipal sensory trigeminal nucleusMesencephalic trigeminal nucleusTrigeminal motor nucleusRetrotrapezoid nucleusaction potentialresting membrane potentialreversal potentialenhanced yellow fluorescent proteinenhanced green fluorescent proteinPatch clampbacterial artificial chromosomeparafacial respiratory groupglycine transporter 2Erev
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Authors
Kouta Nagoya, Shiro Nakamura, Keiko Ikeda, Hiroshi Onimaru, Atsushi Yoshida, Kiyomi Nakayama, Ayako Mochizuki, Masaaki Kiyomoto, Fumihiko Sato, Kiyoshi Kawakami, Koji Takahashi, Tomio Inoue,