Metabotropické

Metabotropic refers to a type of receptor in cell signaling that is indirectly activated by a neurotransmitter or hormone. Unlike ionotropic receptors, which directly open ion channels when bound by a ligand, metabotropic receptors initiate a cascade of intracellular events. This cascade typically involves a G protein, a molecule that then influences the activity of other enzymes or ion channels within the cell. This indirect mechanism leads to a slower but often more prolonged and diverse cellular response compared to ionotropic receptors.

The activation of a metabotropic receptor begins when its corresponding ligand binds to the extracellular portion of the receptor. This binding causes a conformational change in the receptor, which in turn activates an associated G protein. The activated G protein then dissociates into its subunits and can interact with various effector molecules, such as adenylyl cyclase or phospholipase C. These effectors can then produce second messengers like cyclic AMP (cAMP) or inositol trisphosphate (IP3), which diffuse within the cell and trigger a series of downstream effects. These effects can include changes in gene expression, alterations in protein phosphorylation, or modulation of ion channel permeability.

Metabotropic receptors play crucial roles in numerous physiological processes, including neurotransmission, hormone action, and sensory perception. For instance, many neurotransmitters, such as dopamine, serotonin, and acetylcholine, exert their effects through metabotropic receptors. The diversity of signaling pathways modulated by metabotropic receptors allows for fine-tuning of cellular responses, contributing to complex behaviors and physiological regulation. Their slow but sustained actions make them important for processes requiring gradual changes rather than rapid on/off switching.