| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 European Neuroscience Institute Göttingen, Waldweg 33, 37073 Göttingen, Germany2 Department of Neurophysiology, University of Tokyo, Graduate School of Medicine, Tokyo 113-0033, Japan3 Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Medical School, University of Ljubljana, Zalo
ka 4, 1000 Ljubljana, Slovenia; Celica, Stegne 21, 1000 Ljubljana, Slovenia
We have prepared fresh pituitary gland slices from adult and, for the first time, from newborn mice to assess modulation of secretory activity via voltage-activated Ca2+ channels (VACCs). Currents through VACCs and membrane capacitance have been measured with the whole-cell patch-clamp technique. Melanotrophs in newborns were significantly larger than in adults. In both newborn and adult melanotrophs activation of VACCs triggered exocytosis. All pharmacologically isolated VACC types contributed equally to the secretory activity. However, the relative proportion of VACCs differed between newborns and adults. In newborn cells L-type channels dominated and, in addition, an exclusive expression of a toxin-resistant R-type-like current was found. The expression of L-type VACCs was up-regulated by the increased oestrogen levels observed in females, and was even more emphasized in the cells of pregnant females and oestrogen-treated adult male mice. We suggest a general mechanism modulating endocrine secretion in the presence of oestrogen and particularly higher sensitivity to treatments with L-type channel blockers during high oestrogen physiological states.
(Received 18 December 2003;
accepted after revision 8 January 2004;
first published online 14 January 2004)
Corresponding author M. Rupnik: European Neuroscience Institute Göttingen, Waldweg 33, 37073 Göttingen, Germany. Email: mrupnik{at}gwdg.de
This article has been cited by other articles:
|
|
 |
|
  T. Rose, S. Efendic, and M. Rupnik Ca2+-Secretion Coupling Is Impaired in Diabetic Goto Kakizaki rats J. Gen. Physiol., June 1, 2007; 129(6): 493 - 508. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Dudanova, S. Sedej, M. Ahmad, H. Masius, V. Sargsyan, W. Zhang, D. Riedel, F. Angenstein, D. Schild, M. Rupnik, et al. Important Contribution of {alpha}-Neurexins to Ca2+-Triggered Exocytosis of Secretory Granules J. Neurosci., October 11, 2006; 26(41): 10599 - 10613. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Sedej, T. Rose, and M. Rupnik cAMP increases Ca2+-dependent exocytosis through both PKA and Epac2 in mouse melanotrophs from pituitary tissue slices J. Physiol., September 15, 2005; 567(3): 799 - 813. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-E. Turner, S. Sedej, and M. Rupnik Cytosolic Cl- ions in the regulation of secretory and endocytotic activity in melanotrophs from mouse pituitary tissue slices J. Physiol., July 15, 2005; 566(2): 443 - 453. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
