Control of protein phosphatase I in the dendrite

Communication between nerve cells is mediated by both electrical and chemical signals. Chemical neurotransmission can be further categorized into fast and slow components. Fast acting neurotransmitters directly influence neuronal electrical excitability by binding to cell surface receptors which serve as ligand-gated ion channels, thereby directly modulating membrane potential and cell firing. Neurotransmitter receptors may otherwise modulate neuronal excitability indirectly, by coupling to intracellular signalling pathways that impact on the functional activity of ligand- and voltage-gated ion channels, ion pumps, and the machinery for chemical neurotransmission. These indirect actions are relatively slow, and often involve cascades of protein phosphorylation which serve to alter the biochemical activities of substrate proteins, and hence cellular physiology.