Effects of intragastric infusion of inosine monophosphate and L: -glutamate on vagal gastric afferent activity and subsequent autonomic reflexes.
In this study we investigated the effects of intragastric infusion of palatable basic taste substances (umami, sweet, and salty) on the activity of the vagal gastric afferent nerve (VGA), the vagal celiac efferent nerve (VCE), and the splanchnic adrenal efferent nerve (SAE) in anesthetized rats. To test the three selected taste groups, rats were infused with inosine monophosphate (IMP) and L: -glutamate (GLU) for umami, with glucose and sucrose for sweet, and with sodium chloride (NaCl) for salty. Infusions of IMP and GLU solutions significantly increased VGA activity and induced the autonomic reflex, which activated VCE and SAE; these reflexes were abolished after sectioning of the VGA. Infusions of glucose, sucrose and NaCl solutions, conversely, had no significant effects on VGA activity. These results suggest that umami substances in the stomach send information through the VGA to the brain and play a role in the reflex regulation of visceral functions.
Physiology and Nutrition Group, Institute of Life Sciences, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, 210-8681, Japan.
Akihiko
A
Kitamura
Wataru
W
Sato
Hisayuki
H
Uneyama
Kunio
K
Torii
Akira
A
Niijima
D000818:Animals; D017776:Autonomic Pathways / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D018698:Glutamic Acid / Q000494:pharmacology*; D007291:Inosine Monophosphate / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology; D013270:Stomach / Q000187:drug effects* / Q000294:innervation*; D013395:Sucrose / Q000494:pharmacology; D013649:Taste / Q000187:drug effects / Q000502:physiology; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology*
D007291:Inosine Monophosphate; D018698:Glutamic Acid; D012965:Sodium Chloride; D013395:Sucrose; D005947:Glucose