The Sound of Evolution
Remifentanil
Mechanism of action:
Remifentanil is an opioid and belongs to the phenylpiperidine opioid derivatives. It acts mainly on the μ-opioid receptor. The μ-opioid receptor is a Gi/o protein-coupled receptor. Once activated, it inhibits adenylyl cyclase, reduces cAMP production, and subsequently inhibits presynaptic voltage-gated Ca2+ channels, preventing calcium from entering the cell. This reduces the release of pain-related neurotransmitters such as glutamate and substance P, thereby decreasing pain signal transmission. It also activates postsynaptic potassium channels, causing membrane hyperpolarization and lowering the probability of neuronal firing.
Reference(s):
1. Scott LJ et al. (2005). Spotlight on remifentanil for general anaesthesia. CNS Drugs.
2. Warner DS et al. (1996). Intracranial pressure and hemodynamic effects of remifentanil versus alfentanil in patients undergoing supratentorial craniotomy. Anesth Analg.