Dietary cholesterol impairs memory and memory increases brain cholesterol and sulfatide levels.

Cholesterol and sulfatides play many important roles in learning and memory. To date, our observations about the effects of cholesterol on learning have been assessed during response acquisition; that is, the learning of a new memory. Here, we report for the first time to our knowledge, on the effect of a cholesterol diet on a previously formed memory.

Analysis of long-term cognitive-enhancing effects of bryostatin-1 on the rabbit (Oryctolagus cuniculus) nictitating membrane response.

Previous work demonstrated that protein kinase C (PKC) is implicated in learning and memory. This study investigated whether: (i) PKC activated by bryostatin-1 (Bryo) just before or just after sessions of classical conditioning was capable of enhancing classical conditioning of the rabbit nictitating membrane response; (ii) improved behavioral performance matched the time course of PKC activation induced by Bryo; and (iii) vitamin E (Vit E) enhanced the efficacy of Bryo. Paired rabbits received daily trace conditioning with a tone conditioned stimulus and a corneal air puff unconditioned stimulus.

Classical conditioning of the rabbit's nictitating membrane response is a function of the duration of dietary cholesterol.

Modifying dietary cholesterol may improve learning and memory but very high cholesterol can cause pathophysiology and death. Rabbits fed 2% cholesterol for 8, 10 or 12 weeks with 0.12 ppm copper added to distilled water and rabbits fed a normal diet without copper added to distilled water (0 weeks) were given a difficult trace classical conditioning task and an easy delay conditioning task pairing tone with corneal air puff.

High dietary cholesterol facilitates classical conditioning of the rabbit's nictitating membrane response.

Studies have shown that modifying dietary cholesterol may improve learning and that serum cholesterol levels can be positively correlated with cognitive performance. Rabbits fed a 0, 0.5, 1 or 2% cholesterol diet for eight weeks and 0.

Cholesterol enhances classical conditioning of the rabbit heart rate response.

The cholesterol-fed rabbit is a model of atherosclerosis and has been proposed as an animal model of Alzheimer's disease. Feeding rabbits cholesterol has been shown to increase the number of beta amyloid immunoreactive neurons in the cortex. Addition of copper to the drinking water of cholesterol-fed rabbits can increase this number still further and may lead to plaque-like structures.

Effects of 4-aminopyridine on classical conditioning of the rabbit (Oryctolagus cuniculus) nictitating membrane response.

A large body of data suggests that potassium channels may play an important role in learning and memory. Previous in-vitro research in a number of species including Hermissenda and the rabbit suggests that a 4-aminopyridine-sensitive transient potassium channel may be involved in classical conditioning. We investigated the effects of in-vivo 4-aminopyridine administration (0.