Heuss C Gerber U 2000 Two classes of receptors transduce neurotransmitter signals: ionotropic receptors and heptahelical metabotropic receptors. Whereas the ionotropic receptors are structurally associated with a membrane channel, a mediating mechanism is necessary to functionally link metabotropic receptors with their respective effectors. According to the accepted paradigm, the first step in the metabotropic transduction process requires the activation of heterotrimeric G-proteins. An increasing number of observations, however, point to a novel mechanism through which neurotransmitters can initiate biochemical signals and modulate neuronal excitability. According to this mechanism metabotropic receptors induce responses by activating transduction systems that do not involve G-proteins. https://sonar.ch/global/documents/210499 eng info:eu-repo/semantics/altIdentifier/doi/10.1016/s0166-2236(00)01643-x info:eu-repo/semantics/altIdentifier/pmid/11006463 Trends in neurosciences. - 2000 Animals Gene Expression Regulation Heterotrimeric GTP-Binding Proteins Humans Invertebrates MAP Kinase Signaling System Models, Neurological Nerve Tissue Proteins Neurotransmitter Agents Receptor Protein-Tyrosine Kinases Receptors, Growth Factor Receptors, Metabotropic Glutamate Receptors, Neurotransmitter Signal Transduction Synaptic Transmission Transcriptional Activation Vertebrates src-Family Kinases G-protein-independent signaling by G-protein-coupled receptors. http://purl.org/coar/resource_type/c_6501