Oxypinnatanine, a unique derivative of glutamic acid or glutamine with a furfuryl
group increased the total time of NREM sleep by an oral administration. However
the mechanism by which oxypinnatanine promotes sleep remains to be clarified.
In this study, the effect of oxypinnatanine on heat release of freely moving
mice from peripheral blood vessel was demonstrated by using thermography. Oxypinnatanine
given at 30 mg kg-1 indicated the transient skin temperature elevation
from 2 min after its administration but the skin temperature was decreased from
32 min after. Therefore, it is possible that the thermal release associated
with the dilation of peripheral vessels is one of the mechanisms of oxypinnatanine
about its promoting sleep. In addition, the effects of amino acid amides (30
mg kg-1) which isolated from Hemerocallis fulva var. sempervirens
was also examined. As a result, pinnatanine and kwansonine A decreased the
temperature, while longitubanine A, longitubanine B and kwansonine B did not.
As changes in body temperature are generally associated with concomitant changes
in sleep propensity and the effects of sleep promoting substances are related
to changes in thermoregulation. Therefore, it is possible that the monitoring
on heart release from peripheral blood vessel with the use of thermography might
enable the search for substances which induce sleep.