Abstract
2', 3'-Di-o-nicotinoyl riboflavin-4'(5')-phosphate (DNRP) caused a pharmacological action at relatively large dose. (1) Acute toxity of DNRP was studied in mice and rats (see TABLE 1). (2) DNRP decreased spontaneous motor activity in mouse (200〜300mg/kg, i.p.), rat (200〜300mg/kg, i.p.), and dog (50〜100mg/kg, i.v.). (3) DNRP (50mg/kg, s.c.) prolonged the sleeping time of pentobarbital sodium in mouse (40mg/kg, i.p.), but did not show analgesic effect. (4) DNRP (0.15〜0.3%) showed the more effective local anesthetic action than procaine did. (5) DNRP (50mg/kg, s.c.) inhibited the passage of charcoal meal through intestine. (6) DNRP decreased the tonus of isolated rabbit intestine and inhibited the spontaneous movement of isolated rat uterus. (7) DNRP depressed (nonspecifically) the contractive response of guinea pig ileum and rat uterus induced by acetylcholine, histamine, serotonine (5HT), BaCl_2,angiotensin and bradykinin. (8) DNRP potentiated the contractive response of isolated guinea pig vas deferens induced by tyramine, ephedrine, norepinephrine, epinephrine and phenylephrine.
