D1 receptor antagonist
A D1 receptor antagonist prevents the activation of the dopamine D1 receptor. The D1 receptor is coupled to stimulatory G-proteins, which dissociate from the receptor on agonist binding and initiate secondary messenger signaling mechanisms. This causes cell depolarisation, which is inhibited by antagonist binding.
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References
How drugs act: molecular aspects. In: Pharmacology, 4th edition. Rang HP, Dale MM and Ritter JM. Edinburgh, UK: Harcourt Publishers Ltd, 2001:2–46.
Other peripheral mediators: 5-hydroxytryptamine and purines. In: Pharmacology, 4th edition. Rang HP, Dale MM and Ritter JM. Edinburgh, UK: Harcourt Publishers Ltd, 2001:539–49.