Neuro-Humoral Coding of Sleep by the Physiological Sleep Factor Delta

Investigations on neuro-humoral coding of sleep were as yet chiefly focussed on amino-acids and biogenic amines such as serotonin. A possible involvement of peptides in the regulation of sleep was hardly ever taken into consideration. If a neuro-humoral coding of sleep exists, its first demonstration should be the neuro-humoral transmission of sleep.