TRPC4 and GIRK channels underlie neuronal coding of firing patterns that reflect G q/11 –G i/o coincidence signals of variable strengths

Abstract

Significance Neurons communicate by releasing neurotransmitters, many of which act at G protein–coupled receptors. Although it is well known that G q/11 accelerates action potential firing while G i/o inhibits firing, how firing patterns change in response to simultaneous activation of G q/11 and G i/o remains elusive, especially because the relative strength of G q/11 versus G i/o activation varies greatly from event to event. This study reveals that neurons encode distinct messages that reflect coincident G q/11 and G i/o stimulation by activating two ion channels, TRPC4 and GIRK. The resulting firing patterns, composed of burst, pause, and firing recovery phases, reflect both the occurrence of coincident G q/11 and G i/o activation and their relative strengths. With these, we may begin to interpret the language of neurons.