Behavioral and neurochemical effects of a chronic choline-deficient diet in the rat

No Acute Effects of Choline Bitartrate Food Supplements on Memory in Healthy, Young, Human Adults

Choline is a dietary component and precursor of acetylcholine, a crucial neurotransmitter for memory-related brain functions. In two double-blind, placebo-controlled cross-over experiments, we investigated whether the food supplement choline bitartrate improved declarative memory and working memory in healthy, young students one to two hours after supplementation. In experiment 1, 28 participants performed a visuospatial working memory task. In experiment 2, 26 participants performed a declarative picture memorization task. In experiment 3, 40 participants performed a verbal working memory task in addition to the visuospatial working memory and declarative picture task. All tasks were conducted approximately 60 minutes after the ingestion of 2.0–2.5g of either choline bitartrate or placebo. We found that choline did not significantly enhance memory performance during any of the tasks. The null hypothesis that choline does not improve memory performance as compared to placebo was strongly supported by Bayesian statistics. These results are in contrast with animal studies suggesting that choline supplementation boosts memory performance and learning. We conclude that choline likely has no acute effects on cholinergic memory functions in healthy human participants.

Dietary choline deprivation impairs rat brain mitochondrial function and behavioral phenotype

Dietary choline deprivation (CD) is associated with behavioral changes, but mechanisms underlying these detrimental effects are not well characterized. For instance, no literature data are available concerning the CD effects on brain mitochondrial function related to impairment in cognition. Therefore, we investigated brain mitochondrial function and redox status in male Wistar rats fed a CD diet for 28 d. Moreover, the CD behavioral phenotype was characterized. Compared with rats fed a control diet (CTRL), CD rats showed lower NAD-dependent mitochondrial state III and state IV respiration, 40% lower complex I activity, and significantly higher reactive oxygen species production. Total glutathione was oxidatively consumed more in CD than in CTRL rats and the rate of protein oxidation was 40% higher in CD than in CTRL rats, reflecting an oxidative stress condition. The mitochondrial concentrations of cardiolipin, a phospholipid required for optimal activity of complex I, was 20% lower in CD rats than in CTRL rats. Compared with CTRL rats, the behavioral phenotype of CD rats was characterized by impairment in motor coordination and motor learning assessed with the rotarod/accelerod test. Furthermore, compared with CTRL rats, CD rats were less capable of learning the active avoidance task and the number of attempts they made to avoid foot shock was fewer. The results suggest that CD-induced dysfunction in brain mitochondria may be responsible for impairment in cognition and underline that, similar to the liver, the brain also needs an adequate choline supply for its normal functioning.

Regional differences in gastrointestinal motility disturbances during acute necrotising pancreatitis

Patients with acute pancreatitis often suffer from intestinal motility disturbances but the mechanism of this dysfunction is largely unknown. We studied the effect of acute necrotising pancreatitis (ANP) on in vivo gastrointestinal motility and in vitro intestinal contractility in mice. ANP was induced non-invasively by feeding young female mice a choline-deficient ethionine-supplemented (CDE) diet during 72 h. Gastric emptying and intestinal transit were measured in vivo 15 min after intragastric gavage of a semiliquid Evans blue bolus. Gastric and intestinal neuromuscular function was determined in vitro on isolated muscle strips. ANP significantly decreased gastric emptying from 61.2 +/- 9.8 to 34.9 +/- 7.1% and intestinal transit from 63.4 +/- 5.6 to 32.5 +/- 5.4%. ANP did not affect receptor-dependent and receptor-independent gastric muscle contractions except the contractions to substance P, which were slightly inhibited. In intestinal muscle strips, ANP significantly decreased contractions to EFS, carbachol, PGF(2alpha), substance P and KCl. Our results show that ANP delays gastric emptying in vivo, associated with a specific reduction in substance P contractility in vitro. ANP also impairs intestinal transit in vivo, associated with a non-specific reduction of intestinal contractility in vitro. We conclude that ANP impairs gastrointestinal motility in mice with underlying regional differences in the pathogenic mechanisms.

Prenatal dietary choline supplementation decreases the threshold for induction of long-term potentiation in young adult rats

Choline supplementation during gestation in rats leads to augmentation of spatial memory in adulthood. We hypothesized that prenatal (E12-E17) choline supplementation in the rat would lead to an enhancement of hippocampal synaptic plasticity as assessed by long-term potentiation (LTP) at 3-4 mo of age. LTP was assessed blindly in area CA1 of hippocampal slices with first suprathreshold (above threshold for LTP generation in control slices) theta-burst stimulus trains. The magnitude of potentiation after these stimuli was not different between slices from control and prenatally choline supplemented animals. Next, threshold (reliably leading to LTP generation in control slices) or subthreshold theta-burst stimulus trains were applied to slices from control, prenatally choline-supplemented, and prenatally choline-deprived rats. Threshold level stimulus trains induced LTP in slices from both the control and choline-supplemented rats but not in those from the choline-deficient rats. Subthreshold stimulus trains led to LTP induction in slices from prenatally choline-supplemented rats only. These observations indicate that prenatal dietary manipulation of the amino acid, choline, leads to subsequent significant alterations of LTP induction threshold in adult animals.