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Published on: November 18, 2010

Influence of polyvalent cations on the activation of muscle end plate receptors

D H Lambert, R L Parsons

    The Journal of General Physiology
    |September 1, 1970
    PubMed

    Insights

    Polyvalent cations like calcium and lanthanum significantly influence end plate receptor activation in frog muscle. These ions modulate receptor sensitivity and response, impacting neuromuscular transmission.

    Area of Science:

    • Neuroscience
    • Muscle Physiology
    • Pharmacology

    Background:

    • Polyvalent cations are known to affect neurotransmission.
    • Their specific role in postjunctional receptor activation requires further elucidation.

    Purpose of the Study:

    • To investigate the in vitro influence of polyvalent cations on end plate receptor activation in frog sartorius muscle.
    • To determine the effects of calcium, magnesium, and lanthanum on receptor sensitivity and response.

    Main Methods:

    • Experiments were conducted on isolated frog sartorius muscle fibers.
    • Receptor activation was studied using depolarizing quaternary ammonium salts, carbamylcholine, and acetylcholine.
    • The impact of varying extracellular concentrations of calcium, magnesium, and lanthanum was assessed.

    Main Results:

    • Extracellular calcium absence reduced receptor sensitivity; optimal activation occurred at 1.8 mM calcium.
    • Magnesium was less effective than calcium in regulating receptor sensitivity, with peak response at 8 mM.
    • Lanthanum enhanced end plate responses to acetylcholine and carbamylcholine, increasing conductance and miniature end plate potential (MEPP) parameters.

    Conclusions:

    • Polyvalent cations, including calcium, magnesium, and lanthanum, play a crucial role in modulating postjunctional membrane receptor function.
    • These cations influence receptor activation and ion channel properties, extending beyond their known prejunctional effects.

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