Injection Of Ion Research Articles

Impairment of Passive and Active Avoidance Produced by Destruction of the Cholinergic Projection from the Pedunculopontine Nucleus to the Medial Thalamus of the Rat

Areas of pedunculopontine nuclei (PPN) of rats were Iesioned bilaterally by local injection of ibotenic acid. The medial thalamus (MT) where the cholinergic efferent fibers of the PPN terminate was also Iesioned bilaterally by local injection of ethylcholine mustard aziridinium ion. Testing of these Iesioned rats for passive as well as active avoidance behaviors revealed that their avoidance ability was severely impaired. In both PPN- and MT-lesioned rats, the choline acetyltransferase activity decreased significantly in the MT. These findings suggest that the cholinergic PPN-MT projection plays an important role in learning and memory processes.

Flow injection of lithium ion using chromogenic 14-crown-4 derivatives as extraction-spectrophotometric reagents

A system for flow injection of Li+ has been designed, with use of proton-dissociable chromogenic 14-crown-4 derivatives as the extraction-spectrophotometric reagents, and the analytical conditions have been optimised. This flow injection system showed high selectivity for Li+ reflecting the cation-complexing property of the chromogenic crown ethers. The determination of Li+ in the clinical range in blood under a high Na+ background of 130-160 mM was feasible, with a small sample size (50 microliters) and high sampling rate (more than 100 injections per hour), with this method. The proposed extraction-spectrophotometric flow injection system was, therefore, found to be promising for the efficient determination of Li+ in biological samples, such as blood sera, with a high Na+ background.

Beneficial effects of FKS-508 (AF102B), a selective M1 agonist, on the impaired working memory in AF64A-treated rats.

The effects of FKS-508 [AF102B; cis-2-methylspiro(1,3-oxathiolane-5,3')quinuclidine], a selective M1 muscarinic receptor agonist, were examined to predict the possible activity on memory disorders using a T-maze and radial-arm maze task in experimental amnesia models. The amnesia models were produced by bilateral intracerebroventricular injection of ethylcholine aziridinium ion (AF64A), a selective cholinotoxin, in rats. Repeated administrations of FKS-508 (5 mg/kg/day, i.p.) for 5 weeks significantly ameliorated impaired performance of AF64A-treated rats (AF64A-rats) in a delayed alternation task in the T-maze. Repeated administrations of FKS-508 (1 and 5 mg/kg/day, p.o.) for 5 weeks significantly ameliorated acquisition failures of AF64A-rats in a radial-arm maze task. Single administration of FKS-508 (1 and 5 mg/kg, p.o.) significantly reduced the incorrect choices of AF64A-rats in a radial-arm maze task with 6 hr-delay time. No abnormalities in general behaviors, such as loss of appetite and ataxia, were observed in rats treated with FKS-508 repeatedly during 5 weeks. Our present results showed that FKS-508 can ameliorate memory impairments in AF64A-rats with central cholinergic hypofunction without causing any behavioral abnormalities. FKS-508 may be considered as a candidate for the clinical examination of the cholinergic hypothesis of senile dementia of the Alzheimer type.

Beneficial Effects of FKS-508 (AF102B), a Selective M1 Agonist, on the Impaired Working Memory in AF64A-Treated Rats

AbstractThe effects of FKS-508 [AF102B; cis-2-methylspiro(1,3-oxathiolane-5,3′)quinuclidine], a selective M1 muscarinic receptor agonist, were examined to predict the possible activity on memory disorders using a T-maze and radial-arm maze task in experimental amnesia models. The amnesia models were produced by bilateral intracerebroventricular injection of ethylcholine aziridinium ion (AF64A). a selective cholinotoxin. in rats. Repeated administrations of FKS-508 (5 mg/kg/day, i.p.) for 5 weeks significantly ameliorated impaired performance of AF64A-treated rats (AF64A-rats) in a delayed alternation task in the T-maze. Repeated administrations of FKS-508 (1 and 5 mg/kg/day. p.o.) for 5 weeks significantly ameliorated acquisition failures of AF64A-rats in a radial-arm maze task. Single administration of FKS-508 (1 and 5 mg/kg. p.o.) significantly reduced the incorrect choices of AF64A-rats in a radial-arm maze task with 6 hr-delay time. No abnormalities in general behaviors, such as loss of appetite and ataxia, were observed in rats treated with FKS-508 repeatedly during 5 weeks. Our present results showed that FKS-508 can ameliorate memory impairments in AF64A-rats with central cholinergic hypofunction without causing any behavioral abnormalities. FKS-508 may be considered as a candidate for the clinical examination of the cholinergic hypothesis of senile dementia of the Alzheimer type

A comparison of the rate of clearance of xenon ( 133Xe) and pertechnetate ion ( 99mTcO −4) in murine tumors and normal leg muscles

Xenon-133 is a widely used tracer for clearance measurements to estimate nutritive blood flow. There are however certain difficulties in handling and obtaining the radionuclide. Pertechnetate ion, 99mTcO − 4, is used extensively as a radiotracer in nuclear medicine studies and is easily available. To assess the usefulness of pertechnetate ion for blood flow studies, we have measured the rate of clearance following a local injection of pertechnetate ion and xenon simultaneously in normal mouse leg muscle and in murine tumors (fibrosarcoma and mammary carcinoma) of different sizes. The partition coefficients for the two tracers were also measured. The results indicated that the clearance halftime for pertechnetate ion was consistently greater than that for xenon in the tumors but similar in normal resting muscle. The estimated blood flow values assessed using the two tracers were similar in all cases except for large tumors (> 1.5 g). In this case, pertechnetate ion gave lower values than xenon. The difference could be explained by the large intracapillary distances which occur in poorly vascularized regions of large tumors since pertechnetate is a charged ion and hence might be expected to have limited diffusion capacity. The results indicate that caution is warranted when pertechnetate ion is used as a tracer for measurements of blood flow and for other biological determinations which depend on tissue transport properties.

Effects of Intracerebroventricular Injection of AF64A on Learning Behaviors in Rats

The effects of intracerebroventricular (ICV) injection of ethylcholine aziridinium ion (AF64A) (3 nmole/2 μl, each lateral ventricule), a putative selective cholinotoxin, on learning behaviors and choline acetyltransferase (ChAT) activity were studied in rats. AF64A-treated rats (AF64A-rat) exhibited deficient performance in a passive avoidance task and a delayed alternation task in the T-maze, but demonstrated superior avoidance response in a two-way shuttle avoidance task. These changes in learning behaviors were associated with the selective decrease of hippocampal ChAT activity. Physostigmine (0.1 mg/kg, i.p.) significantly improved the retention latency of AF64A-rats in the passive avoidance task. AF64A-rats receiving physostigmine (0.2 mg/kg, i.p.) exhibited a slight but not significant improvement of performance in the delayed alternation task in the T-maze. These findings suggested that ICV injection of AF64A may be useful for producing an experimental amnesia model with hippocampal cholinergic hypofunction like Senile dementia of the Alzheimer type (SDAT), if appropriate learning tests are selected.

EFFECTS OF INTRAHIPPOCAMPAL INJECTIONS OF THE CHOLINERGIC NEUROTOXIN AF64A ON PRESYNAPTIC CHOLINERGIC MARKERS AND ON PASSIVE AVOIDANCE RESPONSE IN THE RAT

1. The effects of the intrahippocampal injection of ethylcholine mustard aziridinium ion (AF64A) on the following cholinergic markers were examined. 2. Bilateral injection of 10 nmol of AF64A into the dorsal hippocampus caused a loss of choline acetyltransferase (CAT) activity in the dorsal hippocampus, ventral hippocampus, cortex and striatum. 3. This treatment caused significant decreases in ACh contents in the dorsal hippocampus, ventral hippocampus and cortex, but not in the striatum. 4. The step-down latencies during the test trials of both 10 and 50 nmol AF64A-treated groups were significantly shorter than those of vehicle-treated groups. 5. None of the control animals stepped down to the large box where they had previously received a foot shock, but 40% of the 10 nmol and 60% of the 50 nmol AF64A-treated animals stepped down to the large box within 600 s. 6. These results indicate that AF64A treatment produces biochemical and functional deficits in the cholinergic neurons in the CNS.

Field potentials induced by injection of potassium ion into the frog retina: A test of current interpretations of the electroretinographic (ERG) b-wave

Using excised frog retinas, the field potential induced by mechanical intraretinal injection of K+ Reinger's was mapped by a penetrating electrode. The high K+ Ringer's contained 75 mM K+ and the amount per injection was of a sphere about 40-50 micron in diameter. The K+ injection pipette was so made that it also served for recording potentials at the site of K+ injection. The study revealed that: (1) a maximum negativity is produced at the depth of K+ injection; and that (2) the negativity subsides in both directions, proximally and distally; but that (3) when recording from the retinal surfaces, the vitreal side becomes positive relative to the receptor side, irrespective of the retinal depth of K+ injection, excepting for the innermost layer of some 20 micron in thickness where some uncertainty remains. The results indicated that the "neutral zone", as defined as a zone where a high K+ produces no potential differences between the opposite retinal surfaces, is localized very close to the inner limiting membrane. Recent interpretations of the b-wave on the Müller cell hypothesis are discussed on the basis of our results.

Distribution of cadmium in liver and kidneys by loadings of various Cd-complexes and relative metal ratios in the induced metallothioneins

The effects of chelating agents and pre-treatment on the distribution of cadmium in the liver and kidneys and on the relative amounts of cadmium, zinc and copper in the induced metallothioneins were compared by intraperitoneally injecting cadmium with various chelating agents. The co-injections of nitrilotriacetic acid or d-(−)-penicillamine resulted in a distribution of cadmium similar to the injection of the free cadmium ion. The co-injections of 2,3-dimercapto-1-propanol or ethylenediamine tetra-acetate resulted in a distribution intermediate between that of the free cadmium ion and the thionein-bound cadmium. Cadmium was recovered mainly from the kidneys for the injection of cadmium-thionein. The changes in the distributions between liver and kidneys were explained tentatively by the stability constants of the complexes from the distribution patterns of cadmium among protein fractions in serum after adding cadmium in vitro with those chelating agents. The copper content in the kidney metallothionein changed depending on the injected form of cadmium and pre-treatment method.

Color in "tungsten trioxide" thin films

We show that evaporated tungsten trioxide amorphous layers commonly used in electrochromic displays actually have the composition WO2.7Hy (0.2<y<0.5). We emphasize that coloration of virgin transparent films can be obtained without injection of any external ion into the layer, and further that around a critical substoichiometry by sputtering, namely, WO2.5, one can prepare blue virgin layers without any hydrogen. The effect of substoichiometry on the valence of tungsten atoms has been followed by XPS measurements of sputtered layers.

ChemInform Abstract: PHOSPHORUS‐NITROGEN COMPOUNDS. 20. THIOPHOSPHORUS HYDRAZONES

AbstractEs werden aus verschiedenen Thio‐phosphor‐hydraziden wie (Ia), (Ib) oder (II) entsprechende Hydrazone hergestellt, wobei als Oxo‐Verbindungen verschiedene Pyridin‐aldehyde, Pyridin‐N‐oxid‐2‐aldehyd, Diacetyl, Diacetylmonoxim oder p‐Bromphenylglyoxal eingesetzt werden.

Influence of the sodium pump on intercellular communication in heart fibres: effect of intracellular injection of sodium ion on electrical coupling.

1. The effect of intracellular sodium injection on the electrical coupling between cardiac Purkinje cells was investigated. 2. It was found that an increase in the intracellular sodium concentration produces uncoupling in about 500 sec and increases the input resistance of the injected cell. Both effects were completely reversible. 3. Inhibition of the sodium pump by ouabain (6-8 x 10(7) M) also causes electrical uncoupling. 4. The decoupling of heart cells achieved by sodium injection was considerably accelerated in fibres treated with ouabain. 5. The influence of sodium injection on cell communication seems to be related to the intracellular calcium concentration 6. The above results indicate that the maintenance of a low intracellular sodium concentration by the sodium pump is essential for the preservation of a high junctional conductance in cardiac fibres.

Electromagnetic ion-cyclotron instabilities in multicomponent magnetospheric plasmas

Growth rates for ion electromagnetic cyclotron (EMC) modes are calculated for several unconventional cases of magnetospheric importance, including total absence of cold plasma and presence of artificially injected heavy-ion plasma. Artificial injection of a very heavy ion such as barium or cesium is likely to suppress, rather than enhance, instability in the important ion-EMC mode, while injection of a light ion like lithium should be very effective in promoting instability in the ring current outside the plasmapause.

Studies in acute renal failure: I. Development of a reproducible lesion in experimental animals

Summary A method is presented for the nontraumatic production of a predictable pigment nephropathy in the rat. This preparation may be graded selectively for specific experimental purposes with respect to incidence, severity and mortality. The contributing features of the setting in which the nephropathy occurs are acid-ash feeding, dehydration and the simultaneous injection of heme pigment and ferrocyanide ion. These features and their interrelationships are explored in some detail. In particular, the combination of heme pigment and ferrocyanide ion is shown to possess a nephrotoxicity greater than that of either material alone. The authors feel that this preparation is suitable for studies relating to the pathogenesis and treatment of acute renal failure.

Role of calcium in contractile excitation of vascular smooth muscle by epinephrine and potassium.

A technique of constant-flow perfusion of isolated segments of dog intestinal arteries was used to investigate the role of calcium in contractile excitation of vascular smooth muscle by epinephrine and potassium. Contractile responses of the arterial muscle to epinephrine, perfused at constant concentration, and to potassium, perfused at high concentration, were both promptly prevented by calcium deionizing accomplished by simultaneous perfusion with solutions containing ethylenediaminetetraacetate (EDTA) for the chelation of available calcium ions. Potassium-induced muscular contracture was removed in a few minutes and epinephrine-induced contractions of potassium-depolarized muscle were soon prevented by perfusion with solutions containing ionic species of EDTA which chelated calcium ions. In muscle depolarized by potassium and calcium deionized by perfusion with solution containing MgK 2 EDTA, the contractile responses to epinephrine were immediately restored by combined perfusate injection of calcium ion and epinephrine. Injections of isosmotic calcium chloride solution of subthreshold or threshold contractile strength, when the artery had been perfused with sodium chloride-rich solution and the muscle had been relaxed, produced much greater contractions during both potassium and epinephrine excitation. The contractions from injected calcium chloride solution were increased by epinephrine excitation of muscle already depolarized by the external application of potassium sulfate, as they were in the previously polarized or resting muscle excited by epinephrine. The thesis is advanced that the relative muscular contractions induced by standard injected volumes of isosmotic calcium chloride solution were a relative index of the calcium influx and calcium permeability of the arterial smooth muscle cells in the various experimental conditions prevailing. Equimolar injections of isosmotic calcium iodide solution produced greater muscular contractions than did injections of isosmotic calcium chloride solution. The possibility is discussed that transmembranous passage of calcium into vascular muscle cells occurs significantly in the form of associated ion pairs. A dual effect of potassium on vascular smooth muscle behavior was observed in that a previously contractile-inducing amount of injected potassium exerted a relaxing effect on the arterial segment perfused with low-potassium solution when the muscle was contracted by epinephrine. It is concluded that: (a) calcium is essentially involved in excitation-contraction coupling of vascular smooth muscle; (b) the calcium permeability and calcium influx of vascular smooth muscle is greatly increased during both epinephrine and potassium excitation of the muscle cells, and epinephrine accomplishes these calcium changes even in muscle already depolarized by potassium; (c) adrenergic neurohormones exert their vasoexcitatory contractile effect by a membrane reaction which is basically nonelectrical and which primarily triggers an increased permeability and influx of calcium into the vascular myoplasm; and (d) the migrated calcium activates intracellularly the myoplasmic events of vascular smooth muscle contraction.