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Published on: September 14, 2012
Melatonin effects on megakaryocyte membrane patch-clamp outward K+ current
Luigi Di Bella1, Carla Bruschi, Luciano Gualano
1Private Laboratory of Physiology, Modena, Italy. luigidibella@libero.it
Background:
This study was carried out to evaluate the influence of melatonin concentration on rat bone marrow megakaryocyte outward K+ current and its implications with regard to platelet production. It is the Authors' view that the greatly extended development of megakaryocyte membrane, together with its ion channels, makes the choice of this topic particularly pertinent.
Material/Methods:
Megakaryocytes from fresh Wistar rat bone marrow were clampaged with patch-clamp technique and the examination of membrane outward current was performed when melatonin dissolved in external or internal standard solution was used.
Results:
On the basis of this study, melatonin does reduce outward K+ current intensity, the more the higher the melatonin concentration. In quantitative terms, whereas no change is noticed when dissolved melatonin concentration in external standard solution is smaller than 25 mM, at 50 mM only a delayed outward current decrease appears. The effect on the outward current intensity is reversible at least until melatonin concentration reaches 500 mM; when melatonin concentration is higher than 1000 mM the effect is demonstrably irreversible. The presence on the megakaryocyte membrane of internal standard melatonin solution does reduce the outward current even more sharply.
Conclusions:
There seems to be a positive correlation between cationic pump and megakaryocyte intimate processes of platelet production.
Insights
Melatonin concentration impacts rat bone marrow megakaryocyte outward potassium (K+) current, affecting platelet production. Higher melatonin levels reduce K+ current intensity, with effects becoming irreversible at very high concentrations.
Area of Science:
- Cell Physiology
- Hematology
- Pharmacology
Background:
- Megakaryocyte membrane development and ion channel function are critical for platelet production.
- Investigating melatonin's influence on megakaryocytes is pertinent due to their complex membrane structure.
Purpose of the Study:
- To evaluate the effect of melatonin concentration on rat bone marrow megakaryocyte outward K+ current.
- To understand the implications of these changes for platelet production.
Main Methods:
- Megakaryocytes were isolated from Wistar rat bone marrow.
- Patch-clamp technique was employed to examine membrane outward current.
- Melatonin was applied in external or internal standard solutions.
Main Results:
- Melatonin reduced outward K+ current intensity in a dose-dependent manner.
- Significant reduction was observed at 50 mM melatonin; effects were reversible up to 500 mM.
- Irreversible effects occurred at concentrations above 1000 mM; internal application showed a sharper decrease.
Conclusions:
- A positive correlation exists between cationic pump activity and megakaryocyte platelet production processes.
- Melatonin's modulation of K+ current may influence thrombopoiesis.
