Inhibition of gastric emptying by triterpene saponin, momordin Ic, in mice: roles of blood glucose, capsaicin-sensitive sensory nerves, and central nervous system.
The roles of capsaicin-sensitive sensory nerves and the central nervous system in the inhibitory effect of momordin Ic, a principal saponin constituent in various Chinese and Japanese herbal medicines, such as the fruit of Kochia scoparia (L.) SCHRAD., on gastric emptying were investigated in nonnutrient meal- or nutrient meal-loaded mice. Momordin Ic (12.5-50 mg/kg) significantly inhibited gastric emptying in 1.5% carboxymethyl cellulose sodium salt test meal-loaded mice by 8.4%-60.6%, 40% glucose test meal-loaded mice by 42.8% (50 mg/kg), milk test meal-loaded mice by 36.4% (50 mg/kg), and 60% ethanol test meal-loaded mice by 37.2% (50 mg/kg). The inhibitory effect on the gastric emptying in 1.5% carboxymethyl cellulose sodium salt test meal-loaded mice was potentiated by glucose (2 g/kg, i.v. or 5 g/kg, i.p.), but markedly attenuated by pretreatment with alloxan (50 mg/kg, i.v.) and streptozotocin (100 mg/kg, i.v.), in which the activity of sympathetic nervous system was decreased, or by insulin (1 or 3 U/kg, s.c.). The effect of insulin (1 U/kg) was markedly reduced by glucose (2 g/kg, i.v.), which can directly nourish the brain, but not by fructose (2 g/kg, i.v.), which cannot be used by the brain. The effect of momordin Ic was also attenuated by pretreatment with capsaicin (75 mg/kg in total, s.c.). These results suggest that the inhibition of gastric emptying by momordin Ic is relative to serum glucose and, at least in part, mediated by capsaicin-sensitive sensory nerves and the central nervous system.
Matsuda
H
H
Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto, Japan.
Li
Y
Y
Yamahara
J
J
Yoshikawa
M
M
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002211:Capsaicin / Q000494:pharmacology*; D002490:Central Nervous System / Q000187:drug effects*; D003864:Depression, Chemical; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000503:physiopathology; D004032:Diet; D005746:Gastric Emptying / Q000187:drug effects*; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009475:Neurons, Afferent / Q000187:drug effects*; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000187:drug effects
D001786:Blood Glucose; D007004:Hypoglycemic Agents; C408362:momordin I (Oleanolic Acid); D009828:Oleanolic Acid; D002211:Capsaicin