Haranath P S, Indira G, Krishnamurthy A
Pharmacol Biochem Behav. 1977 Mar;6(3):259-63. doi: 10.1016/0091-3057(77)90023-5.
In unanaesthetized dogs, cholinomimetic drugs and their antagonists, catecholamines and 5HT were injected into vertebral artery placed in a skin loop. Acetylcholine (1 mg), pilocarpine (1-2 mg), nicotine (250-500 microng), eserine (100 microng) and neostigmine (250 microng) produced sleep apart from a few other peripheral effects. Sleep for longer periods followed injections of tubocurarine (1 mg), atropine (50 microng) and hexamethonium (500 microng). Adrenaline (50 microng) and noradrenaline (50-250 microng) did not produce significant effects on behaviour and sleep. 5HT (250-500 microng) also caused sleep.