title: Effect of axotomy and 17β-estradiol on P2X7 receptor expression pattern in the hypoglossal nucleus of ovariectomized mice.
abstract: The objective of the study was to examine whether axotomy and 17β-estradiol affects P2X7 receptor expression and distribution in the hypoglossal nucleus. The left hypoglossal nerve of ovariectomized mice was cut and animals received a single injection of 17β-estradiol (25 μg/100g b.w. in 20% (2-hydroxypropyl)-β-cyclodextrin) or vehicle one hour after axotomy. Mice were sacrificed on day 4 following surgery. The area fraction of P2X7 receptor immunoreactive structures and of CD11b immunolabeled microglia, P2X7 protein concentration, and the immunoreactivity pattern of estrogen receptor (ER) alpha/beta were analyzed on both sides of the hypoglossal nucleus. Following axotomy the area fraction of P2X7 immunoreactive neurons showed a decreasing tendency, while the area fraction of P2X7 immunolabeled microglia increased significantly on the axotomized side compared with the control side in mice injected with vehicle. In animals treated with 17β-estradiol the decrease in area fraction of neural and the increase in area fraction of microglial P2X7 immunostaining on the axotomized side were significantly enhanced compared with animals injected with vehicle. The P2X7 immunoreactivity pattern on the control side of the nucleus remained unchanged after 17β-estradiol injection. Semi-quantitative Western blots revealed no significant difference in P2X7 protein concentration comparing the axotomized side with the control side in either experimental group. The CD11b immunoreactive microglia area fraction increased significantly following axotomy, but was not affected by 17β-estradiol. Neither ER alpha, nor beta colocalized with CD11b. Our results suggest that axotomy induces cell-type specific changes in P2X7 receptor expression, which may be directly regulated by 17β-estradiol through ER alpha or beta in neurons, but not in activated microglia.
authors.affiliation: Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62, Hungary.
authors.forename: B
authors.initials: B
authors.lastname: Barabási
authors.affiliation: Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62, Hungary.
authors.forename: A
authors.initials: A
authors.lastname: Csondor
authors.affiliation: Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62, Hungary.
authors.forename: T
authors.initials: T
authors.lastname: Martín-Pozas
authors.affiliation: Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62, Hungary.
authors.forename: A M
authors.initials: AM
authors.lastname: Pulupa Sánchez
authors.affiliation: 3DHISTECH Ltd. 1121 Budapest, Konkoly-Thege M. út 29-33, Hungary.
authors.forename: G
authors.initials: G
authors.lastname: Antalffy
authors.affiliation: Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62, Hungary.
authors.forename: L
authors.initials: L
authors.lastname: Siklós
authors.affiliation: Instituto de Neurociencias, IdISSC, Hospital Clínico San Carlos, Universidad Complutense, c/ Prof Martín Lagos s/n, 28040 Madrid, Spain.
authors.forename: U
authors.initials: U
authors.lastname: Gómez-Pinedo
authors.affiliation: Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62, Hungary.
authors.forename: Á
authors.initials: Á
authors.lastname: Párducz
authors.affiliation: Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62, Hungary. Electronic address: hoyk.zsofia@brc.mta.hu.
authors.forename: Z
authors.initials: Z
authors.lastname: Hoyk
mesh_terms: D000818:Animals; D019771:Axotomy; D015153:Blotting, Western; D004958:Estradiol / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D005455:Fluorescent Antibody Technique; D007002:Hypoglossal Nerve / Q000502:physiology; D007150:Immunohistochemistry; D008526:Medulla Oblongata / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010052:Ovariectomy; D058486:Receptors, Purinergic P2X7 / Q000032:analysis / Q000096:biosynthesis*
chemical_list: D058486:Receptors, Purinergic P2X7; D004958:Estradiol
keywords: P2X7 receptor; axotomy; estrogen receptor; hypoglossal nucleus; microglia