• La Universidad
    • Historia
    • Rectoría
    • Autoridades
    • Secretaría General
    • Pastoral UC
    • Organización
    • Hechos y cifras
    • Noticias UC
  • 2011-03-15-13-28-09
  • Facultades
    • Agronomía e Ingeniería Forestal
    • Arquitectura, Diseño y Estudios Urbanos
    • Artes
    • Ciencias Biológicas
    • Ciencias Económicas y Administrativas
    • Ciencias Sociales
    • College
    • Comunicaciones
    • Derecho
    • Educación
    • Filosofía
    • Física
    • Historia, Geografía y Ciencia Política
    • Ingeniería
    • Letras
    • Matemáticas
    • Medicina
    • Química
    • Teología
    • Sede regional Villarrica
  • 2011-03-15-13-28-09
  • Organizaciones vinculadas
  • 2011-03-15-13-28-09
  • Bibliotecas
  • 2011-03-15-13-28-09
  • Mi Portal UC
  • 2011-03-15-13-28-09
  • Correo UC
- Repository logo
  • English
  • Català
  • Čeština
  • Deutsch
  • Español
  • Français
  • Gàidhlig
  • Latviešu
  • Magyar
  • Nederlands
  • Polski
  • Português
  • Português do Brasil
  • Suomi
  • Svenska
  • Türkçe
  • Қазақ
  • বাংলা
  • हिंदी
  • Ελληνικά
  • Yкраї́нська
  • Log in
    Log in
    Have you forgotten your password?
Repository logo
  • Communities & Collections
  • All of DSpace
  • English
  • Català
  • Čeština
  • Deutsch
  • Español
  • Français
  • Gàidhlig
  • Latviešu
  • Magyar
  • Nederlands
  • Polski
  • Português
  • Português do Brasil
  • Suomi
  • Svenska
  • Türkçe
  • Қазақ
  • বাংলা
  • हिंदी
  • Ελληνικά
  • Yкраї́нська
  • Log in
    Log in
    Have you forgotten your password?
  1. Home
  2. Browse by Author

Browsing by Author "Llona, I"

Now showing 1 - 2 of 2
Results Per Page
Sort Options
  • No Thumbnail Available
    Item
    Allopregnanolone-induced modification of presynaptic basal and K+-induced [3H]-norepinephrine efflux from rat cortical slices during the estrous cycle
    (1998) Belmar, J; Cuellar, C; Llona, I; Arancibia, S; Kusch, C; Tapia-Arancibia, L; Pinter, A; Perez, H
    Superfused frontal slices of cerebral cortex were preloaded with [H-3]-norepinephrine ([H-3]NE). Basal [H-3]NE efflux and Kf-induced [H-3]NE release were studied during the estrous cycle and in the presence of neurosteroids. Basal [H-3]NE efflux showed estrous cycle-related variations, with lowest values found during estrus and diestrus II. Allopregnanolone (10(-9) M) potentiated basal [H-3]NE efflux from the Ist minute of its application; the effect of the steroid was still present after 20 min. This effect was also dependent upon the estrous cycle, since basal [H-3]NE efflux was mainly increased during estrus diestrus I, and to a lesser degree only during proestrus. During diestrus II and after ovariectomy, basal [H-3]NE efflux was no longer affected by the neurosteroid. In the presence of yohimbine (10(-6) M), the effect of allopregnanolone on basal efflux was potentiated only during the first 3 min but vanished thereafter. Allopregnanolone (10(-9) M) potentiated the K+-induced [H-3]NE release during estrus, but pregnenolone (10(-9) M) was ineffective, suggesting specificity of the neurosteroid. Yohimbine (10(-6) M) also potentiated K+-induced [H-3]NE release. When applied simultaneously with allopregnanolone (10(-9) M), a potentiating effect on [H-3]NE release was observed. The present results suggest that allopregnanolone is a neurosteroid able to modulate norepinephrine release in the cerebral cortex in an estrous cycle-dependent manner, and that the effect could involve noradrenergic alpha-2 receptors.
  • Loading...
    Thumbnail Image
    Item
    Respiratory responses to pH in the absence of pontine and dorsal medullary areas in the newborn mouse in vitro
    (ELSEVIER, 2003) Infante, CD; von Bernhardi, R; Rovegno, M; Llona, I; Eugenin, JL
    The contribution of pons and dorsal medulla in establishing the pattern of fictive respiration and in mediating the respiratory response to acidification was studied using the isolated brainstem-spinal cord preparation from neonatal mouse. About 40% of ponto-medullary preparations (retaining pons) showed spontaneous, but irregular respiratory-like rhythm. In the other 60%, the elimination of the pons often was followed by the initiation of a respiratory-like rhythm. Medullary preparations, derived from either inactive or rhythmic ponto-medullary preparations, showed a regular respiratory-like rhythm, which was also of a higher frequency and a bigger amplitude than that observed in ponto-medullary preparations. In contrast, ventral medullary preparations, derived from medullary preparations by eliminating the dorsal medulla, showed an irregular rhythm with a reduced amplitude of the integrated inspiratory burst. In ponto-medullary and ventral medullary preparations, acidification of the superfusion medium increased the respiratory frequency, while in medullary preparations, it increased the frequency and reduced the amplitude of the inspiratory burst. Our results suggest that pontine structures influence negatively the rate and depth of the respiratory-like rhythm, while dorsal medullary structures influence positively the depth of the rhythm. They also suggest that the pattern of response to pH supported by the ventral medulla is modified by the input provided from pons and dorsal medulla. (C) 2003 Elsevier B.V. All rights reserved.

Bibliotecas - Pontificia Universidad Católica de Chile- Dirección oficinas centrales: Av. Vicuña Mackenna 4860. Santiago de Chile.

  • Cookie settings
  • Privacy policy
  • End User Agreement
  • Send Feedback