Presence of a non-NMDA glutamate receptor subtype in the sympathetic nervous system of neonatal swine.
For the first time, the GluR-1 subtype of AMPA receptor was identified in the sympathetic nervous system of neonatal swine, an animal model of human development and heart disease. The rationale was to seek evidence of a role ascribed to glutamate in cardiorespiratory regulation in the laboratory rat. The receptor was demonstrated with the avidin-biotin immunoperoxidase technique by using an affinity-purified polyclonal antibody judged to be specific to Glu-R1 in several species. Glu-R1 immunoreactivity was regionally distributed in the thoracic spinal gray, and present intracellularly in neurons and within the surrounding neuropil. Sympathetic preganglionic neurons in the intermediolateral cell column of upper and lower thoracic spinal segments were intensely labeled and surrounded by labeled neuropil. High concentrations of Glu-R1 distinguished laminae II: substantia gelatinosa and the outer region of lamina III. Laminae I and V of the dorsal horn but not IV contained immunolabeled neurons. Arrays of moderately immunoreactive perikarya extended from an intermediate zone of laminae VII to the central gray. Glia and perivascular processes were not labeled, confirming previous observations [Tachibana, M., Wenthold, R.J., Morioka, H., Petralia, R.S., 1994. Light and electron microscopic immunocytochemical localization of AMPA-selective glutamate receptors in the rat spinal cord. J. Comp. Neurol. 344, 431-454]. Neuronal staining patterns corroborated evidence in rats indicating a postsynaptic localization of Glu-R1 associated with plasma membranes and cytoplasmic organelles [Martin, L.J., Blackstone, C.D., Levey, A.I., Huganir, R.L., Price, D.L., 1993. AMPA glutamate receptor subunits are differentially distributed in rat brain. Neuroscience 53, 327-358.; Rubio, M.E., Wenthold, R.J., 1997. Glutamate receptors are selectively targeted to postsynaptic sites in neurons. Neuron 18, 939-950]. Our data predict a role for L-glutamate in postnatal development of cardiorespiratory reflexes in swine.
Ruggiero
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DA
Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, NY 10032, USA.
Gootman
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PM
Sica
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D000818:Animals; D000831:Animals, Newborn; D006321:Heart / Q000502:physiology; D006801:Humans; D007223:Infant; D009046:Motor Neurons / Q000737:chemistry / Q000502:physiology; D018091:Receptors, AMPA / Q000032:analysis* / Q000502:physiology; D018092:Kainic Acid Receptors / Q000032:analysis* / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate; D012018:Reflex / Q000502:physiology; D012119:Respiration; D013398:Sudden Infant Death; D013552:Swine; D013564:Sympathetic Nervous System / Q000737:chemistry* / Q000166:cytology / Q000502:physiology*
D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate