2 Receptor mechanisms and their role in drug interactions: effects of anaesthetics on G-protein-activated intracellular signalling pathways

Abstract

Different types of receptor-mediated mechanism play a key role in cellular transmembrane communication. The majority of plasma membrane receptors mediate the effects of neurotransmitters and hormones through activation of GTP-binding proteins (G-proteins). Coupling of the activated receptor to a G-protein initiates (occasionally inhibits) a cascade of enzyme-catalysed reactions leading to the production of one or more second messengers, eventually leading to the physiological response. The most commonly known cascades are the phosphoinositide and the cAMP route. This paper will describe the key concepts of G-protein-mediated signalling of both cascades and introduce the concept of ‘cross-talk’. Further, the effects of anaesthetics on the intracellular components of these signalling pathways will be reviewed.