@article {819, title = {Effects of L-citrulline Diet on Stress-induced Cold Hypersensitivity in Mice}, journal = {Pharmacognosy Research}, volume = {6}, year = {2014}, month = {August,2014}, pages = {297-302}, type = {Original Article}, chapter = {297}, abstract = {

Background: L-citrulline is an amino acid discovered in watermelon (Citrullus lanatus, Cucurbitaceae) and is a known component of the nitric oxide (NO) cycle that plays an important role in adjusting blood circulation and supplying NO and a key component of the endothelium-derived relaxing factor. Objective: The objective of this study is to evaluate the effect of L-citrulline on a newly established stress-induced cold hypersensitivity mouse model. Materials and Methods: When normal mice were forced to swim in water at 25{\textdegree}C for 15 min, their core body temperature dropped to 28.9{\textdegree}C, and then quickly recovered to normal temperature after the mice were transferred to a dry cage at room temperature (25{\textdegree}C). A 1-h immobilization before swimming caused the core body temperature to drop to ca. 24.1{\textdegree}C (4.8{\textdegree}C lower than normal mice), and the speed of core body temperature recovery dropped to 57\% of the normal control. We considered this delay in recovery from hypothermia to be a sign of stress-induced cold hypersensitivity. Similar cold hypersensitivity was induced by administration of 50 mM L-NG-nitroarginine methyl ester, a NO synthesis inhibitor. Results: In this study, we showed that recovery speed from the stress-induced hypothermia remarkably improved in mice fed a 1\% L-citrulline-containing diet for 20 days. Furthermore, the nonfasting blood level of L-arginine and L-citrulline increased significantly in the L-citrulline diet group, and higher serum nitrogen oxide levels were observed during recovery from the cold. Conclusions: These results suggested that oral L-citrulline supplementation strengthens vascular endothelium function and attenuates stress-induced cold hypersensitivity by improving blood circulation.

}, keywords = {Citrullus lanatus, Cold hypersensitivity, Cucurbitaceae, L-citrulline, Nitric oxide}, doi = {10.4103/0974-8490.138269}, author = {Yoshinori Kobayashi and Kazuki Narita and Kotaro Chiba and Hiroaki Takemoto and Masahiko Morita and Koji Morishita} }