The hypothalmic peptides named the orexins, or hypocretins, were discovered
in 1998. In 1999 it was established that genetic narcolepsy could be cause
d by mutations in the genes synthesizing these peptides or their receptors.
In September of 2000 it was found that most human narcolepsy is caused by
loss of hypocretin cells, most likely as a result of a degenerative process
. This paper reviews these events and their implications for our understand
ing of brain arousal and motor control systems. (C) 2001 American College o
f Neuropsychopharmacology. Published by Elsevier Science Inc.