agonist//antagonist biological approach saq

hi! i'm so confused about whether we can use the antanova study (acetylcholine and scopolamine) for a question that specifically asks about antagonists. savemyexams and inthinking and themantic are all saying opposing things and i'm SO LOST. i know ACh is an inhibitory neurotransmitter but does it count as an endogenous agonist as well? i.e. can i use it in an saq that asks about agonists specifically? or is it only for antagonists (scopolamine) please help!!!