Ion Channels of Pituitary Gonadotrophs and Their Roles in Signaling and Secretion
2017
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Prikaz svih podataka o dokumentuApstrakt:
Gonadotrophs are basophilic cells of the anterior pituitary gland specialized to secrete gonadotropins in response to elevation in intracellular calcium concentration. These cells fire action potentials (APs) spontaneously, coupled with voltage-gated calcium influx of insufficient amplitude to trigger gonadotropin release. The spontaneous excitability of gonadotrophs reflects the expression of voltage-gated sodium, calcium, potassium, non-selective cation-conducting, and chloride channels at their plasma membrane (PM). These cells also express the hyperpolarization-activated and cyclic nucleotide-gated cation channels at the PM, as well as GABAA, nicotinic, and purinergic P2X channels gated by γ-aminobutyric acid (GABA), acetylcholine (ACh), and ATP, respectively. Activation of these channels leads to initiation or amplification of the pacemaking activity, facilitation of calcium influx, and activation of the exocytic pathway. Gonadotrophs also express calcium-conducting channels at the endoplasmic reticulum membranes gated by inositol trisphosphate and intracellular calcium. These channels are activated potently by hypothalamic gonadotropin-releasing hormone (GnRH) and less potently by several paracrine calcium-mobilizing agonists, including pituitary adenylate cyclase-activating peptides, endothelins, ACh, vasopressin, and oxytocin. Activation of these channels causes oscillatory calcium release and a rapid gonadotropin release, accompanied with a shift from tonic firing of single APs to periodic bursting type of electrical activity, which accounts for a sustained calcium signaling and gonadotropin secretion. This review summarizes our current understanding of ion channels as signaling molecules in gonadotrophs, the role of GnRH and paracrine agonists in their gating, and the cross talk among channels.
Ključne reči:
Calcium signaling; Electrical activity; Gonadotrophs; Gonadotropin-releasing hormone; Ligand-gated channels; Luteinizing hormone secretion; Voltage-gated channelsIzvor:
Frontiers in Endocrinology, 2017, 8, JUN, 126-126Finansiranje / projekti:
- Ćelijska i molekulska osnova neuroinflamacije: potencijala ciljna mesta za translacionu medicinu i terapiju (RS-MESTD-Integrated and Interdisciplinary Research (IIR or III)-41014)
- National Institute of Child Health and Human Development Intramural Program—Project ZIA HD 000195-22
- Grant Agency of the Czech Republic (16-12695S), LQ1604 NPU II provided by MEYS
- Z.1.05/1.1.00/02.0109 BIOCEV provided by ERDF and MEYS
DOI: 10.3389/fendo.2017.00126
ISSN: 1664-2392
PubMed: 28649232
WoS: 000402957600001
Scopus: 2-s2.0-85020538536
URI
http://journal.frontiersin.org/article/10.3389/fendo.2017.00126/fullhttps://radar.ibiss.bg.ac.rs/handle/123456789/2783