Calcium affects OX1 orexin (hypocretin) receptor responses by modifying both orexin binding and the signal transduction machinery

摘要

Background and PurposeOne of the major responses upon orexin receptor activation is Ca²⁺ influx, and this influx seems to amplify the other responses mediated by orexin receptors. However, the reduction in Ca²⁺, often used to assess the importance of Ca²⁺ influx, might affect other properties, like ligand−receptor interactions, as suggested for some GPCR systems. Hence, we investigated the role of the ligand−receptor interaction and Ca²⁺ signal cascades in the apparent Ca²⁺ requirement of orexin-A signalling.