PubMed Health⌕ Search

Biomedical subjects

R Ishitani

Publications and source records attributed to R Ishitani.

13 recordsLinked to original sources
PubMed1991

Effect of phospholipase A2 on temperature-induced high-affinity [3H]tryptamine binding sites in rat brain.

To investigate a link between membrane phospholipids and tryptamine binding molecules, we examined the effects of phospholipases A2 and D on the temperature-sensitive high-affinity [3H]tryptamine binding sites in rat brain. When the phospholipase A2-treated membranes were exposed to 1% bovine serum albumin (BSA) before assaying for [3H]tryptamine binding, a complete dose-dependent inhibition curve was observed. At a concentration of 0.03 U, the action of phospholipase A2 resulted in the splitting of phosphatidylserine (PS), choline phosphatides (PC) and ethanolamine phosphatides (PE) by about 32, 34 and 65%, respectively, and reduced [3H]ligand binding by about 32%. On the contrary, in the case of phospholipase D (500 U), PS and PC decreased by about 8% and 33% and PE by about 29% with no significant alteration in the binding capacity. Moreover, Scatchard analysis of the [3H]tryptamine binding showed that phospholipase A2 drastically increased only the KD value of the high affinity sites, and this was accompanied by a decrement of the Bmax values of both the high and low affinity binding sites. From these results, it is inferred that certain lipids (PS) may be a modulator for the function of the temperature-induced high-affinity [3H]tryptamine binding molecules.

Animals↗
PubMed1979

Partial purification and immunological aspects of carboxylesterase from rat liver microsomes.

Carboxylesterase (CEase) was solubilized from rat liver microsomes by autolysis followed by cholate treatment and then purified by the combination of ammonium sulfate fractionation, gel filtration, chromatography on DEAE Sephadex A-50 and hydroxyapatite and preparative Disc electrophoresis. The overall purification was 25-fold with a yield of 6% of the original enzyme activity. Analytical Disc electrophoresis of the final enzyme preparation showed a single band. However, SDS polyacrylamide gel electrophoresis revealed one main band of 93% and three other minor bands. To investigate the interaction between CEases of rat, monkey, pig and rabbit liver microsomes, rabbit antibody to the above enzyme preparation was prepared and immunological analyses, i.e., Ouchterlony's test and immunoelectrophoresis, were performed. In the comparative double diffusion test, the partial fusion of precipitation line between anti-rat CEase and the enzymes of other species was observed. In the second analysis, sharp arc precipitation lines also could be seen in all specimens and, furthermore, mobilities of each enzyme were different. These observations suggest that rat liver CEase seems to be immunologically related in part but not completely identical with the CEases of other species and the charge difference may exist in these specimens.

Animals↗
PubMed1978

Binding of H3-imipramine, H3-dimetacrine and S35-chlorpromazine to synaptosomes.

Binding of H3-imipramine, H3-dimetacrine and S35-chlorpromazine to synaptosomes of rat cerebral cortex was studied using a centrifugation method, and kinetic analysis of the experimental data. Three psychotropic drugs were shown to be rapidly bound to synaptosomes at 2 degrees C, representing a typical binding mode with two classes of binding components, i.e., saturable and non-saturable binding. A double reciprocal plot of the saturable binding component of these drugs revealed that H3-dimetacrine and S35-chlorpromazine represented a single binding mode, whereas H3-imipramine showed a multiple one. When the synaptosomes were treated by freezing and thawing 15 times, a high affinity binding component of H3-imipramine was not observed, while the other two drugs showed a single binding mode as well as those of the undisrupted synaptosomes. To investigate the specificity of this multiple binding mode, comparative binding studies of H3-imipramine were carried out using myelin fragments of rat cerebral cortex. In the myelin fragments preparation, two typical classes of binding mode as shown in the synaptosomes were also recognized. However, a double reciprocal plot of the saturable binding component showed only a straight line, i.e., single binding mode. These findings suggest that imipramine has multiple binding sites to synaptosomes and a high affinity binding component is affected by freezing and thawing procedure.

Acridines↗
PubMed1978

Butanol extracts from myelin fragments-II. Some properties of 5-hydroxytryptamine binding.

The myelin fragments of rat brain stem were treated with butanol-water mixtures, and the butanol extracts (total extract=TE) were incubated with 5 x10(-7) M of C14.5-HT. After incubation, protein, lipid phosphorus and radioactivity were analyzed by Sephadex LH20 column chromatography. Two peaks of components eluted in chloroform-methanol 4:1 (peak I and II) showed the binding capacity for C14.5-HT. The displacement studies with unlabeled 5-HT (5 X 10(-4) M) suggested that peak II was the saturable binding component to 5-HT. On the other hand, butanol extracts from the synaptic membranes of rat brain stem did not show binding for C14.5-HT. Various compounds were studied to determine their inhibitory effects on the saturable binding of 5-HT to TE. The results indicated that acetylcholine, dopamine and tryptamine inhibited the 5-HT binding but LSD, reserpine, colchicine, vinblastine, 5-hydroxytryptophan (5-HTP) and 5-hydroxy-3-indole acetic acid (5-HIAA) had no effect.

Acetylcholine↗
PubMed1977

5-Hydroxytryptamine binding to butanol extracts from myelin fragments.

The myelin fraction of rat brain stem was treated with butanol-water mixtures, and the extracted proteolipids were separated by Sephadex LH20 column chromatography. 2 peaks of proteolipids eluted in chloroform-methanol 4/1 showed the binding capacity for C14 - 5-HT. This finding suggests the necessity of the more careful investigations for the probability of proteolipids as receptor proteins in the central nervous system.

Animals↗
PubMed1977

Studies on the subsynaptosomal distribution of psychotropic drugs in rat cerebral cortex.

After administration of H3-imipramine, H3-dimetacrine and S35-chlorpromazine by the direct lateral intraventricular injection, synaptosomes-rich fraction (F-B) was isolated from rat cerebral cortex by differential and 3-stepwise density gradient centrifugation. The isolated F-B fraction was treated by hyposmotic-lysis followed by freezing and thawing once or 15 times and, furthermore, fractionated into the subsynaptosomal distribution of these drugs showed the same distribution patterns, i.e., the larger portion of radioactivity was recovered in the synaptic ghost membranes-rich fractions. On the other hand, synaptic vesicles-rich fractions contained less radioactivity. On the disrupting process of F-B fraction, when the F-B fraction was treated by hyposmotic-lysis followed by freezing and thawing 15 times, only pellet (FD-6) fraction was obtained as compared with freezing and thawing once (4 interphase layers were obtained). Morphological examination revealed that the synaptic ghost membranes were located in the FD-6 fraction, but morphological damages were not observed. Under these conditions, H3-imipramine showed a 74.1% of release from the synaptosomes, while release with H3-dimetacrine and S35-chlorpromazine was 3.9 and 11.3%, respectively.

Acridines↗
PubMed1976

Eimeria leuckarti infection in foals.

This is the first report on Eimeria leuckarti infection in foals in Japan. Seven Thoroughbred or Angloarabian foals 2 to 7 months of age raised in the Hidaka district, Hokkaido, were infected with E. leuckarti. They died of severe alterations caused by the larval migration of Strongylus vulgaris, and were examined over a period from 1970 to 1973. Protozoa of this species were observed in the small intestine in all the foals. They were found mostly in vacuoles of the cytoplasm of monoclear cells in the lamina propria at or near the tip of villi. Various stages of gametocytes, oocysts, and microgametocytes were found. In infected cells the nucleus was markedly enlarged, but the cellular response was very slight to the parasite.

Animals↗