Tabuchi E, Ono T, Nishijo H, Torii K
Department of Physiology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Physiol Behav. 1991 May;49(5):951-64. doi: 10.1016/0031-9384(91)90208-6.
Rats' preferences for amino acids and NaCl in their drinking behavior were noted when they were fed either a control diet of gluten plus 20% purified egg protein, or (same rats, different time) a lysine-deficient diet. In control, the order of the rats' preferences was arginine greater than saline greater than monosodium L-glutamate (MSG, umami) greater than glycine greater than water greater than threonine greater than histidine greater than lysine. When fed a lysine-deficient diet the order of preference was lysine greater than saline greater than MSG greater than glycine greater than threonine greater than water greater than arginine greater than histidine. To relate neural activity with preference for amino acids and NaCl, activity of lateral hypothalamic (LHA) neurons was recorded during ingestion of MSG, lysine, arginine, glycine, saline, glucose, or water by the control and lysine-deprived condition, following a different cue tone. When the diet was lysine deficient, some neurons responded specifically to lysine ingestion. More neurons responded nondifferentially during licking in control, and responded to lysine, but fewer to other amino acid ingestion during lysine deficiency. Responses to cue tone were associated with those during licking. The present results suggest that preference for deficient amino acids might be mediated in the LHA.
