Which of the following drugs acts by interacting with a G-coupled receptor?
Heroin acts by binding to opiate receptors. Opiate receptors are G-coupled and stimulation leads to inhibition of cellular activity.
Heroin acts by binding to opiate receptors. Opiate receptors are G-coupled and stimulation leads to inhibition of cellular activity.
Illicit drugs (mechanism of action)
Illicit drugs can be classified according to their mechanism of action.
| Mechanism | Examples |
|---|---|
| Drugs which interfere with ionotropic receptors or ion channels | Alcohol, nicotine, benzodiazepines, ketamine |
| Drugs which interfere with G coupled receptors | Opioids, cannabinoids, y-hydroxybutyrate (GHB) |
| Drugs that target monoamine transporters | Amphetamine, ecstasy, cocaine |
The mechanistic classification of addictive drugs. PLoS Medicine, 3: e437.
The main mechanism by which cocaine and amphetamine act is by increasing levels of dopamine in the synaptic cleft. They do this however in slightly different ways.
Cocaine directly blocks the dopamine transporter (Massaro 2002), meaning that dopamine cannot be pumped back into the cell. This results in increased levels of dopamine in the synaptic cleft.
Amphetamine acts via two separate ways (Saunders et al 2000). Firstly it causes the dopamine transporter to internalise (leave the plasma membrane). This lack of dopamine transporters leads to a build up of dopamine in the synaptic cleft. Amphetamine also causes the presynaptic cytoplasmic vesicles to release their dopamine stores and so directly causes an increase of dopamine into the synaptic cleft.
Massaro J. Handbook of Neurotoxicology Volume 2 Humana Press, 2002.
Saunders et al. Amphetamine-induced loss of human dopamine transporter activity: An internalization-dependent and cocaine-sensitive mechanism. PNAS June 6, 2000
