Bromocriptine is agonist of -

Ans. is 'a' i.e., Dopamine Bromocriptineo It is synthetic ergot derivativeo It is a potent dopamine agonist.o It has greater action on D2 receptors, while at certain dopamine sites in brain it acts as partial agonis or antagonist of D1 receptor.o It is also a weak a-adrenergic blocker.o The actions of bromocriptine is due to dopamine like effect (dopaminergic) on D2 and less common D1 receptors.1) Dopamine inhibits the secretion of prolactin - Bromocriptine does the same.2) Dopamine increases the secretion of GH in normal individuals but decreases in acromegalics - Bromocriptine also has same effect.3) Dopamine stimulates CTZ and causes nausea, vomiting - same is true with bromocriptine - Nausea & vomiting are the commonest adverse effects.4) Dopamine decreases GI motility - Bromocriptine has same effect.5) Levodopa is an immediate precursor of dopamine - so, bromocriptine also has levodopa like action in CNS.Other D2 agonists1) Cabergoline- More potent and longer acting D2 agonist than bromocriptine.- It is preferred for acromegaly and hyperprolactinoma.2) Quinagolide- Other D2 agonist effective for hyperprolactinoma.3) Pergolide- D2 agonist.