The effect of Mg2+ and Ca2+ on the excitability of Pacinian corpuscles.
The effect of altering extracellular Ca2+ and Mg2+ levels on electrical properties of Pacinian corpuscles of adult cat has been examined. High Mg2+ solution (5--15 mM) increased the excitability of the receptors and the amplitude of the receptor potential. Ca2+-free EDTA solution caused an increase in the amplitude of the receptor potential in the first 60 min and then its decrease. Mg2+ ions slow down or prevent the depressant effect of the Ca2+ lack on the receptor potential. The phase of the receptor potential amplitude increase in Ca2+-free media was reversibly blocked by tetraethylammonium ions. Treatment with 2,4-dinitrophenol produced a transient increase in the receptor potential amplitude. The threshold of the mechanosensitive receptor membrane was unaffected in Ca2+-free or Mg2+-rich solution. The results suggest that divalent cations are not directly involved in the process of mechanoelectric transformation in Pacinian corpuscles.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002415:Cats; D004305:Dose-Response Relationship, Drug; D008274:Magnesium / Q000494:pharmacology*; D008465:Mechanoreceptors / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects; D010141:Pacinian Corpuscles / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*
D008274:Magnesium; D002118:Calcium