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Y Kitada

Publications and source records attributed to Y Kitada.

72 records · Page 4Linked to original sources
PubMed1984

Beta-adrenoceptor mediated inhibition of behavioral action of desipramine and of central noradrenergic activity in forced swimming rats.

The immobility-reducing action of desipramine (DMI) in forced swimming rats was attenuated by intracerebroventricular (i.c.v.) injection of isoproterenol (ISO) and potentiated by i.c.v. atenolol (ATE), a beta 1-adrenoceptor antagonist. The effect of ISO was blocked by ATE. When administered i.c.v. in normal rats, ISO reduced the contents of 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4), a major metabolite of noradrenaline, in the septal area, thalamus and hypothalamus while ATE had no effect in most of the brain regions. However, in forced swimming rats treated with DMI, ISO reduced MHPG-SO4 in 6 out of 8 brain regions tested and conversely, ATE increased the levels in the amygdala, septal area and hypothalamus. Similar to the behavioral effect, the effect of ISO was antagonized by ATE. These results support the hypothesis that central beta 1-adrenergic mechanisms inhibit the immobility-reducing action of DMI by reducing the activity of noradrenergic neurons in the brain.

Animals↗
PubMed1984

Maintenance of chorda tympani salt taste responses after nerve transection in rats.

To determine whether neurophysiological responses to salts change differentially or in parallel during long recording sessions after nerve transection, we recorded from the cut chorda tympani nerve in rats while stimulating the anterior tongue with NaCl, LiCl, NH4Cl and KCl. In nerve preparations that were not disturbed once recording began, responses were maintained at or above initial magnitudes for an average of 10 h and declined to 50% by 15 h. If the cut end of the nerve was redissected when responses began to decline, stable responses were maintained for an average of 12 h, and did not decline to 50% until 21-24 h. In all rats, responses to the 4 salts altered in parallel for at least 19 h. However in two animals, after 23 h the responses to NaCl and LiCl declined disproportionately, relative to NH4Cl and KCl. Therefore in the course of a typical recording session, i.e. 10-12 h, stable taste responses are obtained and even when responses begin to decline after longer periods, response magnitudes to 4 salts alter in parallel. This indicates that receptor membrane components interacting with specific monochloride salts do not degenerate differentially during the first 19 h after nerve cut.

Ammonium Chloride↗
PubMed1984

Two different receptor sites for Ca2+ and Na+ in frog taste responses.

Distilled water, 1 mM CaCl2 and 500 mM NaCl (pH 4.5) are effective stimuli which excite chemoreceptors of the frog tongue. To learn whether or not these taste stimuli react with different taste receptor sites, a proteolytic enzyme was topically applied to the tongue dorsum. Responses were recorded from the frog glossopharyngeal nerve during taste stimulation. After application of 0.1% pronase E to the dorsal tongue surface, the magnitude of the NaCl response remained unchanged, but the magnitude of the water and CaCl2 responses was markedly decreased. The selective suppression by the pronase E treatment indicates that there are two different receptor sites for Ca2+ and Na+ in the frog taste receptor cell and the receptor sites responsible for the generation of the water and the Ca2+ response may be composed of a protein.

Adaptation, Physiological↗
PubMed1984

High-performance liquid chromatographic analysis of ammonium in human urine.

A method for the quantitative determination of ammonium in human urine by high-performance liquid chromatography (HPLC) is described. After making fluorescent substances with fluorescamine, they were separated and quantified by their fluorometric intensity. The intensity (as measured by peak height) was linear between 0.5 and 5.0 micrograms, and coefficients of variation for elution time and peak height on replicate analysis of the standard were 0.15 and 4.2%, respectively. Recoveries of added ammonium were 96.5 and 97.3%, respectively, on 2.0 and 3.0 micrograms by this method. Detection limit of this method was 0.2 microgram. There was good agreement between the proposed HPLC method (X) and ion chromatographic method (Y), giving the relationships as Y = 0.956X + 0.012, r = 0.991.

Adult↗
PubMed1983

Involvement of alpha- and beta 1-adrenergic mechanisms in the immobility-reducing action of desipramine in the forced swimming test.

The influences of various monoaminergic agents on the immobility-reducing action of desipramine (DMI) in the forced swimming test were examined. 5-Methoxy-N,N-dimethyltryptamine and methysergide, a serotonin agonist and antagonist, respectively, did not affect the duration of immobility. Pimozide, a dopamine antagonist, prolonged the duration of immobility at a dose of 0.5 mg/kg. However, at the doses tested, these drugs had no effect on the action of desipramine. Phenoxybenzamine, an alpha-adrenergic antagonist, prolonged the duration of immobility only with the largest dose (20 mg/kg), but the action of desipramine was completely blocked by this drugs at all doses. Intracerebroventricular injection of a beta-adrenergic agonist, isoproterenol (ISO), and two selective beta 1-adrenergic antagonists, atenolol (ATE) and practolol, dose-dependently diminished and potentiated, respectively, the action of desipramine although these drugs had no effect on the duration of immobility when given alone. A beta 2-adrenergic antagonist derived from oximino-9-fluorene, (IPS 339) did not influence the duration of immobility or affect the action of desipramine. The effect of isoproterenol was almost completely blocked by the pretreatment with atenolol and practolol but not by IPS 339. Subcutaneously-injected isoproterenol did not affect the action of desipramine. Isoproterenol and atenolol had no effect on the concentration of desipramine in brain regions. Phenylephrine, a postsynaptic alpha-adrenergic agonist, reduced the duration of immobility as did desipramine, but this action was not affected by isoproterenol and atenolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Further studies on the suppressing effect of isoproterenol on the immobility-reducing action of desipramine in the forced swimming test.

The present study was undertaken to examine whether the suppressing effect of intracerebroventricular (i.c.v.) administration of isoproterenol (ISO) on the immobility-reducing action of desipramine (DMI) in the forced swimming test was mediated through the presynaptic noradrenaline (NA) neurons and presynaptic alpha 2-adrenoceptors in rat brain. As in the case of DMI, phenylephrine (i.c.v.) and yohimbine (i.p.) reduced the duration of immobility. The actions of DMI and yohimbine but not that of phenylephrine were diminished and potentiated by i.c.v. administration of ISO and atenolol, respectively. The suppressing effects of ISO were almost completely blocked by the pretreatment with atenolol. On the other hand, clonidine (s.c.) diminished the action of DMI as did ISO, although clonidine had no effect on the duration of immobility when given alone. The suppressing effect of clonidine was antagonized by the pretreatment with yohimbine at a dose which did not affect the duration of immobility, when given alone, nor influenced the action of DMI, whereas the effect of ISO was not affected by the same dose of yohimbine. These results suggest that the suppressing effect of ISO on the immobility-reducing action of DMI in the forced swimming test is mediated through the presynaptic NA neurons, and ISO acts through the presynaptic beta 1- but not alpha 2-adrenoceptors.

Animals↗
PubMed1983

Ion-pair high performance liquid chromatographic determination of inosinic acid in meat.

An ion-pair high performance liquid chromatographic (HPLC) technique is described for the determination of inosinic acid (IMP) in meat. The compound was extracted with perchloric acid and analyzed without cleanup. IMP is effectively separated, identified, and quantitated by using a reverse phase column, with ultraviolet detection. A C8 stationary phase and tetrabutyl ammonium as counter ion are used. Recovery of IMP added to meat at 500 or 2500 ppm levels was more than 95%; the limit of detection for IMP is 50 ppm.

Animals↗
PubMed1982

Effect of acute and chronic treatment with tricyclic antidepressants on 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4) contents in various regions of rat brain.

1. Effects of acute and chronic treatment with desipramine (DMI) and amitriptyline (AMI) on 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4) levels in eight brain regions were examined in rats. 2. A single injection of DMI decreased MHPG-SO4 levels in all brain regions except the midbrain, whereas the effect disappeared after the chronic treatment except in the septal area. MHPG-SO4 levels in the hippocampus and thalamus were increased after the chronic treatment with the drug. 3. A single and chronic administration of AMI decreased MHPG-SO4 levels in the thalamus and hippocampus, respectively. 4. These results indicate that the effects of acute and chronic treatment with the tricyclic antidepressants on the central noradrenergic systems differ in different regions of rat brain.

Amitriptyline↗
PubMed1982

Simultaneous liquid chromatographic determination of thiabendazole, o-phenylphenol, and diphenyl residues in citrus fruits, without prior cleanup.

A simple, rapid, efficient method has been developed for determining thiabendazole, o-phenylphenol, and diphenyl in citrus fruits by using high performance liquid chromatography, with fluorescence or ultraviolet detection. The compounds are extracted with ethyl acetate and separated from soluble fruit components on a LiChrosorb RP-8 column. Recovery of these compounds added to citrus fruits at 5 or 50 ppm levels was greater than 93%; the limit of detection for the compounds is 1 ppm.

Biphenyl Compounds↗
PubMed1981

Effects of antidepressants in the rat forced swimming test.

Effects of antidepressants and other drugs on the behaviour of rats in the forced swimming test were examined. Acute and chronic administration of antidepressants reduced the duration of immobility during the first 5 or 10 min of a 30 min test by prolonging escape-directed behaviour which appeared only during this period. However, the drugs did not affect the duration of immobility during the last 20 or 25 min, when the rats were in a state of almost complete immobility. In contrast, methamphetamine, caffeine and scopolamine reduced the duration of immobility not only during the first 5 min but also the next 15 or 25 min without prolonging the escape-directed behaviour but by increasing general motor activity. The effect of antidepressants was potentiated by chronic treatment as compared to acute administration. In the chronic experiments, a significant reduction in the duration of immobility was first observed on the 6th day of the treatment. Although a single injection of diphenhydramine caused an effect similar to antidepressants, this effect disappeared after chronic treatment. These results indicate that immobility itself is not affected by antidepressants. However, it is suggested that the reduction in the duration of immobility only during the first 5 min of the test, which was caused by the prolongation of the escape-directed behaviour, and the potentiation of the effect after chronic treatment are an action specific to antidepressants.

Animals↗
PubMed1978

Inhibitory effects of cations on the Ca2+ response of water fibers in the frog tongue.

The effects of various cations on water fibers in the frog (Rana catesbeiana) tongue were investigated. The following results were obtained. 1. Water fibers responded well to Ca2+ and Sr2+. 2. SO2-(4) did not inhibit the Ca2+ response. Cl- at high concentrations had an inhibitory effect on the response to high Ca2+ stimulation. However, when the Ca2+ concentration was low, Cl- did not induce any inhibition. Therefore, low Ca2+ stimulation (0.1 mM CaCl2) was used to examine the inhibitory effect of cation. 3. MgCl2 and MgSO4 strongly inhibited the response to low Ca2+ stimulation. The inhibition by Mg salts was not caused by anion but by Mg2+. 4. The Ca2+ response was inhibited by various cations. The order of the inhibitory effects of cations was as follows: La3+ greater than Mn2+ = Mg2+ greater than or equal to Ni2+ greater than Co2+ greater than monovalent cations (Na+, K+, NH4+ and choline+). 5. The Sr2+ response, as well as the Ca2+ response, was inhibited by Na+ and Mg2+.

Animals↗