Scopolamine, atropine

These are muscarinic receptor antagonists.

Oxotremorine, arecoline, muscarine

These are muscarinic receptor agonists. They produce ataxia symptoms when activated (due to binding to the acetylcholine receptor.)

Physostigmine

An acetylcholinesterase inhibitor; it works by preventing the break down of AcH. AcH is implicated in memory consolidation, making this an effective treatment for Alzheimer's patients in the early stages.

Haloperidol, Clozapine, Chlorpromazine

These are antipsychotics. They are D2 receptor antagonists.

Amphetamines

Methamphetamine is a common drug, and one of the most neurotoxic. It has a double-effect; it prevents reuptake of DA and is also a VMAT and COMT inhibitor. This prevents it from leaving the synapse. Since it isn't catabolized, DA is oxidized, producing free radicals that kill neuronal cells.

Bromocriptine

Bromocriptine is a D2-receptor activator used to treat PD.

How does a D2-receptor (an autoreceptor) agonist INCREASE DA levels? Well it doesn't, it DECREASES dopamine! But the dopamine it effects is part of a system that DEACTIVATES motor movement, so you are essentially "disabling the STOP" pathway.

Apomorphine

More to come on Apomorphine. It is a D1 and D2-receptor agonist. Unfortunately it has strong emetic properties (as there are D2 receptors in the area postrema of the medulla that modulate this effect). Has been used to treat Parkinson's. Continued use is ineffective because of receptor desensitization.