Effect of Ca2+-antagonists on virally-induced cell-permeability changes

Area of Science:

• Cell Biology
• Virology
• Biochemistry

Background:

• Sendai virus infection causes changes in cell membrane permeability.
• Extracellular cations like calcium (Ca2+) and manganese (Mn2+) influence these permeability changes.
• Calmodulin is a key calcium-binding protein involved in cellular signaling.

Purpose of the Study:

• To investigate the role of extracellular Ca2+ and Mn2+ in Sendai virus-mediated cell permeability changes.
• To explore the potential involvement of calmodulin in protecting cells against viral-induced membrane damage.
• To examine the effects of Ca2+ channel blockers and calmodulin inhibitors on viral-mediated cell permeability.

Main Methods:

• Cells were infected with Sendai virus.
• Extracellular Ca2+ and Mn2+ concentrations were manipulated.
• Permeability changes and leakage were measured.
• The effects of verapamil, prenylamine, trifluoperazine, and R24571 were assessed.
• Drug concentrations for 50% maximal effect were determined and compared to calmodulin binding affinities.

Main Results:

• Extracellular Ca2+ or Mn2+ lengthened the lag period and reduced leakage during viral infection.
• Drugs like verapamil and trifluoperazine shortened the lag period and increased leakage.
• The effective concentrations of these drugs correlated with their calmodulin binding affinities.
• Calmodulin inhibitors mimicked the effects of Ca2+ depletion.

Conclusions:

• Calmodulin may play a protective role against Sendai virus-induced membrane damage.
• Alternatively, calmodulin-binding drugs might have broader, less specific actions than currently understood.
• Further research is needed to clarify the precise mechanisms and drug specificities involved.