NNC 112 is a selective dopamine D1 receptor antagonists.

(S)-Desmethyl-NNC112 ((+)-Desmethyl-NNC112) is a selective PET radioligand that binds to D-dopamine receptors.

Carsatrin is purinylpiperazine derivative. as cardiotonic and antiarrhythmic. Carsatrin acts as positive inotropic agent that increases twitch tension and prolongs the action potential (AP) duration of ventricular muscle without affecting the Na+, K+-ATPase, adenylyl cyclase, phosphodiesterase isozymes, or cardiac myofilaments. Carsatrin’s positive inotropic effect can be prevented by tetrodotoxin but not by the adrenergic antagonists timolol, yohimbine, or prazosin