“The stimulatory effect of ondansetron (10(-6) M) on electrically evoked contractions was antagonized by yohimbine , a 5-HT2B receptor antagonist, but not by SDZ 205-557 (2-methoxy-4-amino-5-chloro-benzoic acid 2-[diethylamino] ethyl ester), a 5-HT4 receptor antagonist.”
“This stimulatory effect of ondansetron on acetylcholine-induced contractions was antagonized by yohimbine.”