Dissociation of Striatal GTPase and Dopamine Release Responses to Muscarinic Cholinergic Agonists in F344 Rats: Influence of Age and Dietary Manipulation

Abstract: There is evidence that dietary lipids and age both influence neuronal membrane composition and receptor G protein-linked signal transduction, but very little information is available on the interaction between these two factors. To investigate this, we obtained striata from 2, 12, and 22-month-old male F344 rats who were fed either a high-cholesterol, high-saturated fat or low-fat diet for 1 month. The striata were assayed for muscarinic agonist-stimulated low-K_m GTPase activity using 10^?3M carbachol and 10^?5M oxotremorine and for KCl-evoked dopamine release enhancement by 10^?5M oxotremorine. Membrane cholesterol and phospholipid content and phospholipid class composition were also determined. Mature animals showed significant but divergent changes in GTPase activity and dopamine release for high-cholesterol and low-fat diets: GTPase activity decreased, whereas dopamine release increased in these groups. Alterations in GTPase activity but not in dopamine release were inversely correlated with the cholesterol/phospholipid molar ratio. Old control animals showed reductions in both GTPase activity and oxotremorine-enhanced dopamine release compared with young animals. Whereas none of the experimental diets affected GTPase activity in old animals, the low-fat diet produced a marked decrease in dopamine release. In contrast to mature and old groups, young rats showed no significant change in either GTPase or dopamine release, suggesting a relative “resistance” to such dietary lipid modulation. The observed dissociation in GTPase and dopamine release responses to diet may reflect differing effects of these diets on discrete membrane lipid domains that preferentially influence different signal transduction components. The substantial age-related differences in striatal membrane response to dietary lipid modulation may represent the effects of underlying age differences in membrane lipid metabolism, structure, and/or dynamics. Our findings support the work of other groups that have shown that brain membranes are susceptible to modification by exogenous lipids. They also suggest the need for a more systematic examination of the influence of age on the response to other types of dietary lipid changes.     

Differences in the Manifestation of Cell Pluripotence In Vivo and In Vitro in the Mutant Arabidopsis thaliana with the Phenotype of Cell Memory Disorder

Russian Journal of Plant Physiology - Plant cells cultivated in vitro are a convenient model for studying the genetic and physiological mechanisms necessary for the cells to acquire a state of...     

Mitochondrial DNA Variation in Russian Populations of Krasnodar Krai,Belgorod, and Nizhni Novgorod Oblast

Mitochondrial DNA (mtDNA) polymorphism was examined in three Russian populations from the European part of Russia (Krasnodar Krai, Belgorod, and Nizhnii Novgorod oblast). This analysis revealed that mitochondrial gene pool of Russians was represented by the mtDNA types belonging to groups H, V, pre-V, HV*, J, T, U, K, I, W, and X. The major groups (average frequency over 5%) were H, V, J, T, and U. Mongoloid admixture in Russians, constituting only 1%, was revealed in the form of mtDNA types of groups C and D. Analysis of the frequency distribution of the mtDNA type groups indicated the absence of genetic differences between the Russian populations studied.     

Production of a monospecific antiserum to lactoperoxidase using immunoprecipitants

To prepare monospecific antiserum to lactoperoxidase, one of the factors of the nonspecific protection of the body from infections, the complexes of lactoperoxidase with antibodies to it were used as antigens; precipitates were obtained by linear immunoelectrophoresis with the use of partially purified lactoperoxidase and antisera to it. This method does not require obtaining the highly purified enzyme and the subsequent adsorption of antisera.     

Gas-resistance of the woody plants of West Siberia

A resistant of the woody plants in West Siberia to toxic substances (sulfur dioxide, hydrocarbons, and carbon black) is studied by the reaction of the pigment complex, change of acidity of the leaf blade, activity of oxidative enzymes, moisture regime, and degree of damage of the leaf blade. The data of the study can be used in the landscaping of the sanitary protective zones of enterprises.     

The use of microdot immunoenzyme analysis with visual detection for the determination of tularemia antibodies

The possibility of using the micropoint enzyme immunoassay (EIA) on a nitrocellulose membrane with the visual evaluation of results for the detection of tularemia IgG antibodies in hamadryas baboons at the postvaccinal period has been studied. The sensitivity of this assay has been compared with that of the passive hemagglutination (PHA) test, the microagglutination (MA) test and EIA with the spectrophotometric evaluation of results in plates. As shown in this study, EIA in the above-mentioned modification can be successfully used for the detection of tularemia antibodies in the blood serum. The sensitivity of micropoint EIA has proved to be not inferior to that of EIA in plates, while exceeding the sensitivity of the PHA test 10- to 20-fold and the sensitivity of the MA test 10- to 1,000-fold. This method is simple, reliable, highly sensitive, economic and requires no special equipment, which makes it highly promising for the diagnosis of tularemia and the evaluation of humoral immunity at the postvaccinal period.