Watch out the Methoniums скачать в хорошем качестве

Watch out the Methoniums

This song is all about some drugs that share the same suffix - 'methonium'. They are synthetic ligands for the nicotinic receptors. The latter are activated when the natural agonist - acetylcholine binds to specific sites and two molecules of acetylcholine is needed to fully activate the nicotinic receptors to mediate cation influx that results in subsequent depolarisation to the muscle or nerve membrane. The latter belong to the Cys-loop family of the ligand-gated ion channels (LGICs) and thus, they are pentameric meaning a functional nicotinic receptor has five subunits. They typically possess a postively charged quaternary nitrogen atom in their structure, hence the suffix 'onium'. Few of such agents can bind to the same sites where acetylcholine binds to and then to activate the nicotinic receptors as agonists. However, these drugs are not strictly acetylcholine, therefore they are not readily broken down by the enzyme acetylcholinesterase. Examples of such 'methoniums' include suxamethonium and decamethonium. These agents are more selective for skeletal muscle specific nicotinic receptors and they are chemically more stable than acetylcholine and as such, they stay result in stronger stimulation of the nicotinic receptors, causing sustained depolarisation of the skeletal muscle membrane. This causes rapid inactivation of the voltage-gated sodium channels and thus frustrates the neurotransmission at the neuromuscular junction. Because of this, suxamethonium and decamethonium are known as the depolarising type neuromuscular blockers. Currently, only suxamethonium, also known as succinylcholine, is in clinical use as skeleta muscle relaxant. muscle specific nicotinic receptors. Another drug ending with the suffix 'methonium' is Hexamethonium. This agent, unlike suxamethonium and decamethonium, has more selectivity towards ganglionic nicotinic receptors. Hexamethonium's action on the nicotinic receptors is primarily through the block of the ion pore, rather than through competition with the binding site for acetylcholine. In the past, hexamethonium was used as to lower blood pressure. Since all (i.e. both sympathetic and parasympathetic) autonomic ganglionic transmission is affected, hexomethonium's use comes with significant side effects and it is no longer used clinically but used as a research tool in the laboratory as a ganglionic blocker. Sources https://go.drugbank.com/drugs/DB08960 https://go.drugbank.com/drugs/DB01245 https://go.drugbank.com/drugs/DB00202