apomorphine , a dopamine receptor agonist , physostigmine , an anticholinesterase agent and pilocarpine , a cholinergic receptor agonist , produced yawning in rats , with the most effective doses being 0.25 mg/kg , 0.2 mg/kg and 4 mg/kg , respectively .
C0031923
pilocarpine
C3536927
cholinergic receptor agonist