Effects of caerulein and cholecystokinin-octapeptide on acetylcholine and choline contents in the brains of intact and vagotomized mice

The effects of caerulein (CLN; 0.5, 5, and 50 μg/kg, IP) and cholecystokinin-octapeptide (CCK-8; 5, 50, and 400 μg/kg, IP) on the acetylcholine and choline contents in the discrete brain regions were examined, 30, 60, and 120 min after injection into intact and vagotomized mice. In all of the discrete brain regions of the intact mice, CLN and CCK-8 was found to have a complex effect on the acetylcholine and choline contents depending on the brain region, dosage and treatment time. On the other hand, the effect of CLN was abolished completely in the vagotomized mice. Thus, the present study indicates that peripherally administered CLN and CCK-8 have an effect on the central cholinergic system, mainly mediated via the vagus.