Effects of the muscarinic agonist pilocarpine on vigilance states and locomotor activity in ring doves

Cholinergic systems play a significant role in regulating a variety of behavioral functions in mammals and birds. The aim of this work is to study the effects of the muscarinic agonist pilocarpine on behavioral states by visual inspection and electroencephalographic recording; also, locomotor activity was continuously recorded by infrared interruption system in ring doves. The current results in birds demonstrated that the muscarinic agonist pilocarpine (1 and 3 mg/kg, i.p.) primarily induced theta activity in addition to promote passive waking, while diminished active waking, the EEG slow wave rhythm and REM sleep in ring doves. The locomotor activity recorded continuously in ring doves diminished after pilocarpine treatment, which was in good agreement with the observed reduction of active waking derived of the EEG study. Altogether, the current results are similar to the effects of pilocarpine previously reported in mammals. In conclusion, hippocampal theta rhythm in birds suggests that this rhythm is an ancestral property of hippocampal function and similar cholinergic mechanisms regulate vigilance states and theta generation in mammals and birds.