In addition several ligands known to act as agonists at either << 5-HT2A >> or 5-HT2C receptors including 1-m-chlorophenylpiperazine (m-CPP), Ru 24969, [[ MK 212 ]] and SCH 23390 were also agonists in rat fundus whilst sumatriptan, renzapride and 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) were very weak or inactive.