Biochemical Signaling Pathways and Diffusion: Overview
Signaling pathways modulate the function of neurons and neuronal networks through diverse processes. The most well-known function of signaling pathways is synaptic plasticity, which controls neuronal networks via modulation of the strength of synaptic connections. Signaling pathways also are critical for neuronal development, axon guidance, and regulation of transcription and translation. Signaling pathways are activated by the G protein-coupled transmembrane receptors, such as metabotropic glutamate receptors or noradrenergic receptors; by the receptor tyrosine kinases; and by calcium influx through NMDA receptors or voltage-dependent calcium channels.
Due to the importance of calcium, its concentration is tightly regulated by buffers and pumps. One of these calcium buffers, known as calmodulin, is not inert; rather, it can activate diverse enzymes such as adenylyl cyclase, calcineurin, phosphodiesterase type 1B, and calcium-calmodulin-dependent protein...