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001-es BibID:BIBFORM041254
035-os BibID:PMID:22510271
Első szerző:Hrabovszky Erik
Cím:Glutamatergic and GABAergic innervation of human gonadotropin-releasing hormone-I neurons / Erik Hrabovszky, Csilla S. Molnár, Robert Nagy, Barbara Vida, Beáta Á. Borsay, Kálmán Rácz, László Herczeg, Masahiko Watanabe, Imre Kalló, Zsolt Liposits
Megjegyzések:Amino acid (aa) neurotransmitters in synaptic afferents to hypothalamic GnRH-I neurons are critically involved in the neuroendocrine control of reproduction. Although in rodents the major aa neurotransmitter in these afferents is ?-aminobutyric acid (GABA), glutamatergic axons also innervate GnRH neurons directly. Our aim with the present study was to address the relative contribution of GABAergic and glutamatergic axons to the afferent control of human GnRH neurons. Formalin-fixed hypothalamic samples were obtained from adult male individuals (n = 8) at autopsies, and their coronal sections processed for dual-label immunohistochemical studies. GABAergic axons were labeled with vesicular inhibitory aa transporter antibodies, whereas glutamatergic axons were detected with antisera against the major vesicular glutamate transporter (VGLUT) isoforms, VGLUT1 and VGLUT2. The relative incidences of GABAergic and glutamatergic axonal appositions to GnRH-immunoreactive neurons were compared quantitatively in two regions, the infundibular and paraventricular nuclei. Results showed that GABAergic axons established the most frequently encountered type of axo-somatic apposition. Glutamatergic contacts occurred in significantly lower numbers, with similar contributions by their VGLUT1 and VGLUT2 subclasses. The innervation pattern was different on GnRH dendrites where the combined incidence of glutamatergic (VGLUT1 + VGLUT2) contacts slightly exceeded that of the GABAergic appositions. We conclude that GABA represents the major aa neurotransmitter in axo-somatic afferents to human GnRH neurons, whereas glutamatergic inputs occur somewhat more frequently than GABAergic inputs on GnRH dendrites. Unlike in rats, the GnRH system of the human receives innervation from the VGLUT1, in addition to the VGLUT2, subclass of glutamatergic neurons.
Tárgyszavak:Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:Endocrinology. - 153 : 6 (2012), p. 2766-2776. -
További szerzők:Molnár Csilla S. (Budapest) Nagy Róbert (Budapest) Vida Barbara Borsay Beáta Á. (1982-) (igazságügyi orvosszakértő) Rácz Kálmán (1981-) (igazságügyi rezidens) Watanabe, Masahiko Kalló Imre Liposits Zsolt Herczeg László (1954-) (igazságügyi orvosszakértő)
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001-es BibID:BIBFORM041511
Első szerző:Molnár Csilla S. (Budapest)
Cím:Morphological evidence for enhanced kisspeptin and neurokinin B signaling in the infundibular nucleus of the aging man / Molnár C. S., Vida B., Sipos M. T., Ciofi P., Borsay B. Á., Rácz K., Herczeg L., Bloom S. R., Ghatei M. A., Dhillo W. S., Liposits Z., Hrabovszky E.
Megjegyzések:Peptidergic neurons synthesizing kisspeptin (KP) and neurokinin B (NKB) in the hypothalamic infundibular nucleus have been implicated in negative sex steroid feedback to GnRH neurons. In laboratory rodents, testosterone decreases KP and NKB expression in this region. In the present study, we addressed the hypothesis that the weakening of this inhibitory testosterone feedback in elderly men coincides with enhanced KP and NKB signaling in the infundibular nucleus. This central hypothesis was tested in a series of immunohistochemical studies on hypothalamic sections of male human individuals that were divided into arbitrary "young" (21-49 yr, n = 11) and "aged" (50-67 yr, n = 9) groups. Quantitative immunohistochemical experiments established that the regional densities of NKB-immunoreactive (IR) perikarya and fibers, and the incidence of afferent contacts they formed onto GnRH neurons, exceeded several times those of the KP-IR elements. Robust aging-dependent enhancements were identified in the regional densities of KP-IR perikarya and fibers and the incidence of afferent contacts they established onto GnRH neurons. The abundance of NKB-IR perikarya, fibers, and axonal appositions to GnRH neurons also increased with age, albeit to lower extents. In dual-immunofluorescent studies, the incidence of KP-IR NKB perikarya increased from 36% in young to 68% in aged men. Collectively, these immunohistochemical data suggest an aging-related robust enhancement in central KP signaling and a moderate enhancement in central NKB signaling. These changes are compatible with a reduced testosterone negative feedback to KP and NKB neurons. The heavier KP and NKB inputs to GnRH neurons in aged, compared with young, men may play a role in the enhanced central stimulation of the reproductive axis. It requires clarification to what extent the enhanced KP and NKB signaling upstream from GnRH neurons is an adaptive response to hypogonadism or, alternatively, a consequence of a decline in the androgen sensitivity of KP and NKB neurons.
Tárgyszavak:Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Endocrinology. - 153 : 11 (2012), p. 5428-5439. -
További szerzők:Vida Barbara Sipos Máté T. Ciofi, Philippe Borsay Beáta Á. (1982-) (igazságügyi orvosszakértő) Rácz Kálmán (1981-) (igazságügyi rezidens) Herczeg László (1954-) (igazságügyi orvosszakértő) Bloom, Stephen R. Ghatei, Mohammad A. Dhillo, Waljit S. Liposits Zsolt Hrabovszky Erik
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