Changes in activity of choline acetylase in central nervous system of rat after intraventricular administration of noradrenaline

Effects of bifemelane hydrochloride (MCI-2016) on acetylcholine release from cortical and hippocampal slices of rats

Bifemelane hydrochloride (MCI-2016) increased high K+-evoked acetylcholine (ACh) release from cortical and hippocampal slices of rats. The increasing effect of MCI-2016 was abolished in the absence of Ca ion and by pretreatment of reserpine (2.5 mg/kg, i.p.). These results suggest that monoaminergic neurons may be related to the enhancement of ACh release by MCI-2016. High K+-evoked ACh release from cortical slices was significantly decreased during aging. The decrease in ACh release was ameliorated by pretreatment of MCI-2016 (30 mg/kg, i.p.).

The effect of 6-OHDA lesions of the nucleus accumbens septum on schedule-induced drinking, wheelrunning and corticosterone levels in the rat

In a series of four experiments the relationship between 6-OHDA lesions of the nucleus accumbens septum (NAS), schedule-induced behaviors and plasma corticosterone levels was explored. Data from the first experiment show a significant decrease in water intake during a scheduled food delivery test hour for 6-OHDA lesioned groups of rats compared with sham or non-lesioned groups of rats, while during the remaining 23 hours of the day water intake was the same for 6-OHDA lesioned and sham lesioned groups. In a second experiment similar decreases in schedule-induced wheelrunning were observed for 6-OHDA lesioned rats when compared with sham lesioned rats. Data from a third experiment showed significant increases in plasma corticosterone levels of rats in the presence of a scheduled food delivery compared with rats given non-scheduled food. In a fourth experiment it was shown that 6-OHDA lesions of the NAS abolish this increase of corticosterone levels in rats on a food delivery schedule. These data extend the findings of Robbins and Koob [19] and show a more general involvement of the dopaminergic pathways of the NAS in schedule-induced behaviors and in concomitant plasma corticosterone changes.

Effect of physostigmine on Y-maze discrimination retention in the rat

A series of experiments was designed to assess the effect of physostigmine on the retention of an appetitively-reinforced Y-maze discrimination. The results supported in part the model of cholinergic involvement in long-term memory as proposed by Deutsch, in that physostigmine respectively impaired and enhanced well-remembered and poorly-remembered responses. However a modification of the model was presented to accommodate futher findings that variations in both dose-level of administered physostigmine and initial leraning ability influenced subsequent retention, depending on the training-testing interval.