Dopamine receptor

From Free net encyclopedia

The dopamine receptors are a class of metabotropic G-protein-coupled receptors with the neurotransmitter dopamine as their endogenous ligand.

Dopamine receptor types

Dopamine receptor agonists (+) and antagonists (-). Specificity is not always perfect. This table is not complete.

	D1-like			D2-like
	D1	D5		D2	D3	D4
Apomorphine	+	+		+	+	+
Fenoldopam	+	+		+	?	+
SKF 38393	+	+		+
SKF 82958	+	+
Dihydrexidine	+	+
Quinpirole				+	+
Haloperidol	-	?		-	?	?
Flupentixol	-	?		-	?	?
Fluphenazine	-	?		?	?	?
SCH 23390	-	-
Spiperone		?		-	?	?
Raclopride				-	-	-
Clozapine	-	-		-	-	—

There are 5 major types of dopamine receptors. All are G-protein coupled metabotropic receptors, and can be excitatory or inhibitory to the post-synaptic neuron. The D1 and D5 receptors are members of the D1-like family of dopamine receptors whereas the D2, D3 and D4 receptors are members of the D2-like family. Activation of the D1-like family receptors is coupled to increases in cAMP and is typically excitatory, while D2-like activation reduces cAMP and is typically inhibitory.

In schizophrenics, D2 receptors have been found to exist in higher than normal levels, and antipsychotic drugs aim to block these.

References

• Zimmerberg, B., "Dopamine receptors: A representative family of metabotropic receptors, Multimedia Neuroscience Education Project (2002)

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