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Vasoactive intestinal polypeptide alters GH3/B6 pituitary cell excitability
1Department of Biochemistry, Arrhenius Laboratory, University of Stockholm, Sweden.
Pflugers Archiv : European Journal of Physiology
|February 1, 1988
Summary
Vasoactive intestinal peptide (VIP) alters the electrical activity of prolactin-secreting cells, increasing action potential frequency and duration. These changes in membrane excitability may explain VIP's role in stimulating prolactin release.
Area of Science:
- Neuroendocrinology
- Cellular Electrophysiology
Background:
- Prolactin secretion is regulated by various neuroendocrine factors.
- Vasoactive intestinal peptide (VIP) is a known secretagogue for prolactin.
Purpose of the Study:
- To investigate the direct effects of VIP on the membrane excitability of prolactin-secreting cells.
- To elucidate the electrophysiological mechanisms underlying VIP-induced prolactin secretion.
Main Methods:
- Whole-cell patch clamp recording technique was employed.
- Electrophysiological properties of clonal GH3/B6 prolactin-secreting cells were analyzed.
- Effects of submicromolar VIP concentrations were assessed under voltage clamp and current clamp conditions.
Main Results:
- VIP significantly affected membrane excitability in over 50% of tested GH3/B6 cells.
- VIP increased the frequency and prolonged the duration of spontaneous Ca2+-dependent action potentials.
- VIP altered rheobase and induced changes in voltage-sensitive conductances.
Conclusions:
- VIP modulates the electrical activity of prolactin-secreting cells.
- VIP-induced alterations in membrane excitability are likely involved in stimulating prolactin secretion.