GABAergic signaling in the rat pineal gland

Autor: Jong Bae Seo, Estela Muñoz, Luz Estefanía Farías Altamirano, Sergio Gonzalo Benitez, Martin Kruse, Bertil Hille, Seung-Ryoung Jung, Duk Su Koh, Haijie Yu
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: CONICET Digital (CONICET)
Consejo Nacional de Investigaciones Científicas y Técnicas
instacron:CONICET
DOI: 10.1111/jpi.12328
Popis: Pinealocytes secrete melatonin at night in response to norepinephrine released from sympathetic nerve terminals in the pineal gland. The gland also contains many other neurotransmitters whose cellular disposition, activity, and relevance to pineal function are not understood. Here, we clarify sources and demonstrate cellular actions of the neurotransmitter γ-aminobutyric acid (GABA) using Western blotting and immunohistochemistry of the gland and electrical recording from pinealocytes. GABAergic cells and nerve fibers, defined as containing GABA and the synthetic GAD67, were identified. The cells represent a subset of interstitial cells while the nerve fibers were distinct from the sympathetic innervation. The GABAA receptor subunit α1 was visualized in close proximity of both GABAergic and sympathetic nerve fibers as well as fine extensions among pinealocytes and blood vessels. The GABAB 1 receptor subunit was localized in the interstitial compartment but not in pinealocytes. Electrophysiology of isolated pinealocytes revealed that GABA and muscimol elicit strong inward chloride currents sensitive to bicuculline and picrotoxin, clear evidence for functional GABAA receptors on the surface membrane. Applications of elevated potassium solution or the neurotransmitter acetylcholine depolarized the pinealocyte membrane potential enough to open voltage-gated Ca2+ channels leading to intracellular calcium elevations. GABA repolarized the membrane and shut off such calcium rises. In 48–72-h cultured intact glands, GABA application neither triggered melatonin secretion by itself nor affected norepinephrine-induced secretion. Thus, strong elements of GABA signaling are present in pineal glands that make large electrical responses in pinealocytes, but physiological roles need to be found. Fil: Yu, Haijie. University of Washington; Estados Unidos Fil: Benitez, Sergio Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina Fil: Jung, Seung-Ryoung. University of Washington; Estados Unidos Fil: Kruse, Martin. University of Washington; Estados Unidos Fil: Seo, Jong Bae. University of Washington; Estados Unidos Fil: Koh, Duk-Su. University of Washington; Estados Unidos Fil: Muñoz, Estela Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina Fil: Hille, Bertil. University of Washington; Estados Unidos
Databáze: OpenAIRE
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