Is depakote a dopamine antagonist?

No: According to our current understanding, Depakote work by altering calcium current, sodium channel, and the synthesis and breakdown of gaba, the main inhibitory neurotransmitter in the brain.

No: It does not block Dopamine neurotransmission. It is believed to have a stabilizing effect on neural electrical hyperactivity, this it was developed to help control seizures or epilepsy. That is how some 'mood swings' may not be, strictly speaking, 'bipolar' as a seizure disorder of mood-regulating structures of the brain, the limbic system, could give you a very similar set of symptoms.

Depakote: Nope. It is an Anti-convulsant & Mood stabilizing medication, also used for Migraine prophylaxis.