Impact of Magnesium on Oxytocin Receptor Function.

BACKGROUND AND PURPOSE

The intranasal administration of oxytocin (OT) reduces migraine headaches through activation of the oxytocin receptor (OTR). Magnesium ion (Mg concentration is critical to the activation of the OTR, and a low serum Mg concentration is predictive of a migraine headache. We, therefore, examined the functional impact of Mg concentration on OT-OTR binding efficacy using two complimentary bioassays.

EXPERIMENTAL APPROACH

Current clamp recordings of rat trigeminal ganglia (TG) neurons measured the impact of Mg on an OT-induced reduction in excitability. In addition, we assessed the impact of Mg on intranasal OT-induced craniofacial analgesia in rats.

KEY RESULTS

While OT alone dose-dependently hyperpolarized TG neurons, decreasing their excitability, the addition of 1.75 mM Mg significantly enhanced this effect. Similarly, while the intranasal application of OT produced dose-dependent craniofacial analgesia, Mg significantly enhanced these effects.

CONCLUSIONS AND IMPLICATIONS

OT efficacy may be limited by low ambient Mg levels. The addition of Mg to OT formulations may improve its efficacy in reducing headache pain as well as for other OT-dependent processes.