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Divalent cations modulate 5-HT3 receptor-induced currents in N1E-115 neuroblastoma cells
J A Peters1, T G Hales, J J Lambert
1Department of Pharmacology and Clinical Pharmacology, Ninewells Hospital, University of Dundee, U.K.
Abstract:
The influence of extracellular calcium and magnesium ion concentrations upon 5-HT3 receptor-gated membrane currents in murine N1E-115 neuroblastoma cells has been studied under voltage-clamp conditions. A decrease in the concentration of either Ca2+ or Mg2+ from their standard values of 1.0 and 2.0 mM respectively augmented both the amplitude and duration of the 5-HT-induced current, whereas elevating the concentration of either divalent cation produced the opposite effect. Such modulation did not involve a change in the reversal potential of the response.
Insights
Extracellular calcium and magnesium ions significantly influence 5-HT3 receptor currents in neuroblastoma cells. Lowering these ions increases current amplitude and duration, while higher concentrations decrease them.
Area of Science:
- Neuroscience
- Cell Biology
- Biophysics
Background:
- 5-HT3 receptors are crucial ion channels involved in neurotransmission.
- Extracellular divalent cations like calcium (Ca2+) and magnesium (Mg2+) are known to modulate ion channel function.
- Understanding these modulations is key to comprehending neuronal excitability.
Purpose of the Study:
- To investigate the impact of extracellular calcium and magnesium ion concentrations on 5-HT3 receptor-gated currents.
- To determine how changes in Ca2+ and Mg2+ affect the amplitude and duration of 5-HT-induced currents in N1E-115 neuroblastoma cells.
Main Methods:
- Utilized voltage-clamp electrophysiology on murine N1E-115 neuroblastoma cells.
- Systematically altered extracellular concentrations of Ca2+ and Mg2+.
- Measured 5-HT-induced membrane currents.
Main Results:
- Decreased extracellular Ca2+ or Mg2+ augmented the amplitude and duration of 5-HT-induced currents.
- Increased extracellular Ca2+ or Mg2+ reduced the amplitude and duration of these currents.
- The observed modulations did not alter the reversal potential of the 5-HT response.
Conclusions:
- Extracellular calcium and magnesium ions play a significant modulatory role in 5-HT3 receptor channel activity.
- The concentration of these divalent cations directly impacts the magnitude and persistence of 5-HT-mediated signaling.
- These findings contribute to the understanding of ion channel gating and neuronal signaling under varying ionic conditions.