G protein-Coupled Receptor Distribution Impacts the Effectiveness of Signal Transmission.

Numbers of activated receptor dictate efficacy of neurotransmitter stimulation. Many PLC coupled receptors activated by ligands elicit canonical downstream Gq/11 pathway to induce endogenous Ca2+ gated chloride channels. The coupling from receptors to effectors was analyzed in Xenopus oocytes expressing genetically modified angiotensin receptor type 1 receptor (AT1R). The latency between ATII binding and Ca2+-induced Cl- current surge was inversely correlated. AT1R activation triggered a chain of chemical reactions, of which the products were playing messengers for subsequent events. Messenger accumulation must rate-limit the agonism. For accurate quantification the speed of ATII triggered the i Cl-. The T-form AT1R-IRK1 fusion exhibits faster induction compared to the M-form. The latency of the recorded none vanished i Cl-, marking the lowest genuine calcium activation, took place at earlier time point by the timer time. The evoked i Cl- however reached similar maximal amplitudes. This kinetic effect raises the possibility to use temporal coding to complement amplitude coding (analogous to FM versus AM radio transmission) for receptor-agonist pairs.