Ganglionic blocker

A Ganglionic blocker is a type of pharmacological agent that inhibits the action of neurotransmitters at autonomic ganglia. These blockers are primarily used in the treatment of hypertension and other disorders related to the autonomic nervous system.

Mechanism of Action

Ganglionic blockers work by blocking the nicotinic acetylcholine receptors (nAChRs) present in the autonomic ganglia. This prevents the transmission of nerve impulses from the preganglionic neuron to the postganglionic neuron, thereby inhibiting the action of the autonomic nervous system.

Types of Ganglionic Blockers

There are two main types of ganglionic blockers: competitive and non-competitive.

• Competitive Ganglionic Blockers: These blockers, such as hexamethonium, compete with acetylcholine for binding sites on the nAChRs.
• Non-competitive Ganglionic Blockers: These blockers, such as mecamylamine, bind to a different site on the nAChRs, thereby altering the receptor's conformation and preventing acetylcholine from binding.

Clinical Uses

Ganglionic blockers were once widely used in the treatment of hypertension. However, due to their numerous side effects and the development of more effective antihypertensive drugs, their use has declined significantly. Today, they are primarily used in the treatment of severe malignant hypertension when other treatments have failed.

Side Effects

The side effects of ganglionic blockers are primarily due to their inhibition of the autonomic nervous system. These can include dry mouth, blurred vision, constipation, and urinary retention. In severe cases, they can cause orthostatic hypotension, a sudden drop in blood pressure when standing up.

See Also

• Autonomic nervous system
• Neurotransmitter
• Nicotinic acetylcholine receptor
• Hypertension

References

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