Adrenergic Drugs

Sympathomimetic drugs bring about their actions by mediating through their receptors called as adrenoceptors. There are two types of principal adrenoceptors.

1. Alpha receptors

2. Beta receptors

These receptors are further subdivided into subtypes and have been identified by molecular cloning techniques;

• Alpha receptors:

  1. Alpha 1 -Alpha 1A, IB & ID

  2. Alpha 2 -Alpha 2A, 2B & 2C

• Beta receptors:

  1. Beta 1

  2. Beta 2

  3. Beta 3

Dopamine receptors:

The endogenous dopamine produces a variety of responses by interacting with specific dopamine receptors. These receptors are distinct from alpha and beta receptors. Atleast 5 subtypes of receptors have been identified. These receptors have been found in brain, splanchnic and renal vasculature.

Molecular mechanisms of sympathomimetic drugs:

Adrenorecptors are coupled with G protien receptors. The G proteins of particular importance for adrenoceptor function include G-s – the stimulatory G protein of adenylyl cyclase and G-I – the inhibitory G protein of adenylyl cyclase.

Signal transduction mechanism of alpha 1 receptors

Signal transduction mechanism of alpha 2 receptors & Beta receptors

Category: Pharmacology Notes