Gene expression of ionotropic glutamate receptor subunits in the tectofugal pathway of the pigeon. (1st March 2016)

• Record Type: Journal Article
• Authors: Atoji, Y.
• Is Part Of: Neuroscience. Volume 316(2016)
• Page Start: 367
• Page End: 377
• Publication Date: 2016-03-01
• Subjects: AMPA α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor -- DEPC diethyl pyrocarbonate -- DIG digoxigenin -- Ei internal portion of the entopallium -- Ep perientopallium -- EPSPs excitatory postsynaptic potentials -- Ex external portion of the entopallium -- GABA γ-amino butyric acid -- GAD glutamic acid decarboxylase -- HA hyperpallium -- iGluR ionotropic glutamate receptor -- Imc magnocellular part of the isthmic nucleus -- Ipc parvocellular part of the isthmic nucleus -- KA kainate receptor -- NLS N-lauroylsarcosine -- NMDA N-methyl-d-aspartate receptors -- OT optic tectum -- PB phosphate buffer -- PBS phosphate-buffered saline -- Rt rotundal nucleus -- RT-PCR real-time polymerase chain reaction -- SSC standard saline citrate -- TBS Tris-buffered saline -- TBST Tris-buffered saline Tween 20 -- vGluT2 vesicular glutamate transporter 2; AMPA receptor -- kainate receptor -- NMDA receptor -- isthmic nucleus -- vGluT2 -- GAD65; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2015.12.032
• Languages: English
• ISSNs: 0306-4522

Abstract

Highlights: Glutamatergic neurons are located in the tectofugal pathway in the pigeon. iGluR subunits are expressed in relay nuclei in the tectofugal pathway. iGluRs subunits are expressed in isthmic nuclei as well. Glutamatergic circuits in the tectofugal pathway show a diversity of iGluR localization. Abstract: The tectofugal pathway in birds consists of four stations, the retina, optic tectum, rotundal nucleus, and entopallium, and it conveys visual information via three ascending pathways. These pathways consist of retino-tectal, tecto-rotundal and rotundo-entopallial cells, all of which are glutamatergic. The present study examined the localization of ionotropic glutamate receptors (iGluRs) to identify the target areas of glutamatergic projections in the tectofugal pathway in pigeons. Nine subunits of iGluRs were analyzed using in situ hybridization as follows: AMPA receptors (GluA1, GluA2, GluA3, and GluA4), kainate receptors (GluK1, GluK2, and GluK4), and NMDA receptors (GluN1 and GluN2A). Hybridization signals of subunits showed various intensities in different cells. In the optic tectum, a strong to moderate expression was observed in layer 10 (GluA2, GluA3, GluK4, and GluN1) and layer 13 (GluA2, GluK4, GluN1, and GluN2A). The rotundal nucleus intensely expressed GluA3, GluA4, GluK1, and GluK4. In the entopallium, an intense to moderate expression of GluK1 and GluK4, and a moderate to weak expression of AMPA and NMDA receptors were observed. Furthermore, the parvocellular and magnocellular parts of the isthmic nuclei showed a strong expression of GluA2, GluA3, GluK4, and GluN1. The present findings demonstrate the expression of iGluRs in glutamatergic projection targets of the tectofugal pathway in birds and suggest a diversity of iGluRs in the transmission of visual information.