Multiple cytosolic calcium signals and membrane electrical events evoked in single arginine vasopressin-stimulated corticotrophs - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Biological Chemistry Année : 1993

Multiple cytosolic calcium signals and membrane electrical events evoked in single arginine vasopressin-stimulated corticotrophs

Résumé

The action of arginine vasopressin (AVP) on cytosolic free Ca2+ concentration ([Ca2+]i) was investigated in single rat pituitary corticotrophs using indo-1 microfluorimetry, in part in combination with the monitoring of membrane electrical events with the perforated patch-clamp technique. In corticotrophs showing the series of short-lived [Ca2+]i rises (transient pattern) in response to corticotropin-releasing factor, 100 nM AVP evoked either the transient pattern or a [Ca2+]i spike followed by a sustained plateau (spike/plateau pattern). Not all corticotrophs responded to changes in AVP concentration in the same manner. Some cells exhibited a concentration-dependent increase in [Ca2+]i transient activity, whereas others showing the spike/plateau at high AVP concentrations responded to low agonist concentrations by two [Ca2+]i responses: a slow rising step or two to three sinusoidal-like oscillations. Combined [Ca2+]i and patch-clamp recordings as well as manipulation of extracellular Ca2+ showed that both transient pattern and the plateau of spike/plateau response depended on Ca2+ entry mainly through voltage-gated, dihydropyridine-sensitive Ca2+ channels. By contrast, step, oscillations, and spike were due to Ca2+ release from internal stores. These Ca(2+)-mobilizing responses caused the activation of Ca(2+)-activated, apamin-sensitive K+ channels, which led to a membrane hyperpolarization. These results reveal cell-specific [Ca2+]i signals and associated electrical events in individual AVP-stimulated corticotrophs.
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Dates et versions

hal-04210108 , version 1 (18-09-2023)

Identifiants

  • HAL Id : hal-04210108 , version 1
  • PUBMED : 8226740

Citer

J Corcuff, N Guérineau, Pascal Mariot, B Lussier, P Mollard. Multiple cytosolic calcium signals and membrane electrical events evoked in single arginine vasopressin-stimulated corticotrophs. Journal of Biological Chemistry, 1993, 268 (30), pp.22313-22321. ⟨hal-04210108⟩
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