Mg Inhibition of ATP-Activated Current in Rat Nodose Ganglion Neurons: Evidence That Mg Decreases the Agonist Affinity of the Receptor

Li, Chaoying, Robert W. Peoples, and Forrest F. Weight. Mg (Choi and Kim 1996; Kim and Rabin 1994). Although inhiinhibition of ATP-activated current in rat nodose ganglion neurons: bition of ATP-gated receptor channels in neurons by Mg evidence that Mg decreases the agonist affinity of the receptor. has been observed (Krishtal and Marchenko 1984), the J. Neurophysiol. 77: 3391–3395, 1997. The effect of Mg on mechanism for this effect has not been determined. In the ATP-activated current in rat nodose ganglion neurons was investipresent study, we used the whole cell patch-clamp technique gated with the use of the whole cell patch-clamp technique. Mg to investigate the effect of Mg on the function of ATPdecreased the amplitude of ATP-activated current in a concentragated ion channels in freshly isolated rat nodose ganglion tion-dependent manner over the concentration range of 0.25–8 neurons. mM, with a 50% inhibitory concentration value of 1.5 mM for current activated by 10 mM ATP. Mg shifted the ATP concentra-