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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 78 (1982), S. 219-224 
    ISSN: 1432-2072
    Keywords: Morphine ; Naloxone ; Cerebral asymmetry ; Self stimulation ; Rotation ; Reinforcement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats with bilaterally implanted lateral hypothalamic electrodes were tested daily for self-stimulation to each side of the brain, and rotation (circling behavior) was recorded concomitantly. All rats rotated in a preferred direction regardless of the side of the brain stimulated and all rats had asymmetries in self-stimulation sensitivity related to the direction of rotation. Morphine increased rotation and lowered self-stimulation thresholds at low doses (e.g., 2.5 mg/kg) and decreased rotation and raised self-stimulation thresholds at high doses (e.g., 20.0 mg/kg). The changes in self-stimulation thresholds preferentially occurred on opposite sides of the brain, i.e., the low-dose decrease in thresholds was greater in the normally less sensitive side of the brain whereas the high-dose increase in thresholds was greater in the normally more sensitive side of the brain. Naloxone produced no changes in rates of rotation but did elicit small changes in self-stimulation that varied with the side of the brain, i.e., dose-related decreases in thresholds occurred in the normally more sensitive side of the brain whereas dose-related increases in thresholds occurred in the normally less sensitive side of the brain. Subsequently rats were tested in a choice procedure providing concurrent access to rewarding stimulation of either side of the brain; currents were titrated such that, under baseline conditions, rats continually alternated between self-stimulating one side of the brain or the other. Morphine induced a preference for the less sensitive side of the brain that was comparable in magnitude at all doses and independent of its biphasic effects on rates of responding. Naloxone induced a dose-related preference for the more sensitive side of the brain while not altering rates of responding. Naloxone (1.0 mg/kg) also completely antagonized the effects of all doses of morphine. The results are discussed in terms of lateralized actions mediating the discriminable effects of reinforcing drugs.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 40 (1975), S. 329-334 
    ISSN: 1432-2072
    Keywords: Apomorphine ; Rotation ; Caudate Lesions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Apomorphine (i.p.) induced rotational behavior (i.e. circling) in normal unoperated rats. This rotation increased with increasing dose up to 10.0 mg/kg, after which the dose-response curve appeared to plateau. Although there was large variability among rats, rotation for each rat was consistent in both direction and magnitude from week to week. Rotation was not antagonized by alpha-methyl-para-tyrosine. When rats with unilateral lesions of the caudate nucleus were tested with apomorphine, postoperative rotation was significantly influenced by the direction of preoperative rotation; rats rotated more postoperatively if the lesion was made ipsilateral rather than contralateral to their preoperative direction of rotation. These results suggest that there is a bilateral asymmetry of dopaminergic receptors in the nigro-striatal pathways of normal rats.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2072
    Keywords: Rotation ; d-Amphetamine ; Apomorphine ; Scopolamine ; L-Dopa ; Haloperidol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Normal unoperated rats were tested for rotation (i.e., circling behavior) in a spherical “rotometer” and dose-response relationships were generated using d-amphetamine, apomorphine, L-Dopa, haloperidol, and scopolamine. The rotation induced by amphetamine was significantly antagonized by alphamethyl-p-tyrosine and haloperidol, but not by diethyl-dithiocarbamate. The rotation elicited by apomorphine was unaffected by alpha-methyl-p-tyrosine. Rotation was not necessarily in the same direction with high and low doses of amphetamine, or amphetamine and apomorphine administered a week apart from each other. Dopaminergic-cholinergic interactions were evident, since pilocarpine antagonized amphetamine-induced rotation whereas scopolamine did not; scopolamine elicited rotation in the same direction as that induced by amphetamine. Left and right striatal dopamine and tel-diencephalic norepinephrine levels were determined in rats injected with various doses of amphetamine and tested for rotation. There were significant bilateral differences in striatal dopamine which were related to the direction of rotation. Since amphetamine was found to be equally distributed to the two sides of the brain, the difference in striatal dopamine appeared to be the neurochemical substrate for rotation in normal rats. These results suggest that normal rats have asymmetrical levels of striatal dopamine as well as an asymmetrical complement of striatal dopamine receptors.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0878
    Keywords: Cholesterol ; Symbiotes ; Aphids ; Digitonin ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pea aphid primary symbiotes have previously been shown to synthesize cholesterol in vitro. Two electron microscopic techniques were used here to determine whether the symbiotes also synthesize cholesterol in vivo and whether this cholesterol is made available to the aphid. We also inquired into a possible role of secondary symbiotes in cholesterol biosynthesis. Treatment of aphids with digitonin resulted in significant alteration of ultrastructural sites in primary and secondary symbiote membranes. We concluded that these sites are areas of high cholesterol concentration in the symbiotes. Electron microscopic autoradiography with 3H-mevalonate precursor indicated that both primary and secondary symbiotes synthesize cholesterol; in both cases, the majority of grains were associated with the symbiote membranes. While the frequency of grains on the symbiotes remained constant, irrespective of incubation time in labelled media, the frequency of grains over surrounding tissues increased exponentially as the time of incubation was increased from 30 min to 8 h, indicating that symbiote cholesterol is transported to other tissues. High voltage electron microscopic autoradiography permitted thick section autoradiography, reducing the time of emulsion exposure from 54 days (thin section) to 12 days (0.5 μm sections).
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0878
    Keywords: OsO4 ; Cholesterol ; Symbiotes ; Aphids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pea aphids left for 48 h in unbuffered osmium tetroxide show heavy staining of many organelles in the symbiote-containing cells (mycetocytes and sheath), embryos and oenocytes very similar to that characteristic of mammalian sterol-synthesizing cells. However, the staining of the pea-aphid cells is, to a large extent, dependent on the presence of cholesterol benzoate, or free cholesterol, in the aphid's diet. In aphids cultured in vitro with 3H mevalonate in the presence of added cholesterol, the incorporation of label into the cholesterol and lanosterol fractions is significantly reduced. If the dietary cholesterol effects a similar inhibition in vivo, the cholesterol-dependent osmium staining could be due to precursors(s) of cholesterol accumulating in the intracellular sites described. There is also osmium staining of large (normally electron-transparent) vacuoles in mycetocytes, gut and fat body, irrespective of dietary cholesterol.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 148 (1974), S. 287-300 
    ISSN: 1432-0878
    Keywords: Symbiotes ; Aphids ; Antibiotics ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of penicillin and chlortetracyline HCl on the fine structure of the intracellular symbiotes of the pea aphid were studied in an attempt to remove the symbiote population. High penicillin concentrations, 1% and 0.1%, caused symbiote breakdown but were toxic and/or repellent to the aphids; at 0.1% specific effects were observed on the symbiotes' cell walls. After the use of 0.01% penicillin in the aphid diet, the symbiotes had abnormal cell walls and were abnormally dilated; however, symbiote division and transmission from one aphid generation to the next seemed unaffected and the aphids appeared normal. Aphids fed 0.1% chlortetracycline failed to reproduce. After 7 days, their symbiotes were found to break down at a high rate but aphid mitochondria were also adversely affected at this stage. Following 0.002% chlortetracycline, the aphids produced aposymbiotic progeny with apparently normal mitochondrial populations; these larvae failed to develop.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 159 (1975), S. 351-367 
    ISSN: 1432-0878
    Keywords: Symbiotes ; Aphids ; Vesicles ; Organelles ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A detailed investigation into the ultrastructure of the pea aphid mycetocytes and their contained symbiotes and organelles was carried out with the transmission electron microscope. The most striking observation was the presence of small vesicles in the space between the primary symbiote cell wall and membrane envelope (outer membrane space). The vesicles appear to form by a budding process at the outer cell wall layer. Subsequently, the vesicles, we suggest, may move out into the mycetocyte cytoplasm via a similar budding of the membrane envelope. The Golgi apparatus was found to be an important structural component of the primary mycetocyte; it is continuous with the rough endoplasmic reticulum and the latter, in turn, appears to be closely connected to the primary symbiote membrane envelope. This may be of functional significance. A number of other organelles not previously described in mycetocytes were found, including transparent vacuoles, granular bodies, multivesicular bodies and microfilaments. The chemical composition of the various vesicles and organelles is unknown at present.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Apparent second-order rate constants for complex formation between poly (I) and poly (C) and copolymers of C containing non-complementary I or U residues have been determined spectrophotometrically. The rate constants decrease as the concentration of either I or U in the C strands increases-the effect seems insensitive to the species of residue involved, when differences in the thermal stabilities of the poly (I) poly (C,I) and poly (I). poly (C,U) complexes are taken into account. These results suggest that low concentrations of relatively stable defects can alter the apparent kinetic “complexity” of polynucleotides as determined by hybridization methods (C0t analysis).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and antifungal activity of a novel series of 3-aryl-5-[(aryloxy)alkyl]-3-[(1H-imidazol-1-yl)-methyl]-2-methylisoxazolidines and related compounds, are discussed. The synthesis of the title compounds was accomplished via a 1,3-dipolar cycloaddition of α-substituted ketonitrones with l-alkenyl phenyl ethers (Scheme 2 and 3). The compounds were evaluated for in vitro antifungal activity in solid agar cultures against a broad variety of yeast and systemic mycoses and dermatophytes. While antifungal activity was evident throughout the series, in general, derivatives having halogen atom(s) in either or both aryl rings demonstrated the highest potency, especially against Trichophyton rubrum and Candida albicans. The dichloro analog 20 (PR 967-248) was found to possess the most useful activity. Its minimum inhibitory concentration (MIC) values ranged between 0.2 and 2.0 μg/ml, as compared to 0.2-20.0 μg/ml for the standard drug ketoconazole (4).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and antifungal activity of a novel series of 1-[(3,5-bisaryl-2-methylisoxazolidin-3-yl)methyl]-1H-1,2,4-triazoles 6 and 7 (i.e. 8-19) are discussed. The preparation of 8-19 was straightforward and highlighted by a regiospecific 1,3-dipolar cycloaddition of α-substituted (E)-ketonitrones 4 with appropriate atyrene derivatives 5 that led to a cis/trans-diastereoisomeric mixture of the corresponding triazoles (Scheme). The title compounds were evaluated for in vitro antifungal activity in solid agar cultures against a broad array of yeast and systemic mycoses and dermatophytes. The in vivo activity was determined in an immune-compromised mouse model of systemic candidiasis. While the in vitro activity was evident throughout the series, it was moderate in potency. However, some of the triazole derivatives demonstrated a potent in vivo activity comparable to that of the standard drug ketoconazole. Analogue 12 (PR 988-399) emerged as the best overall compound demonstrating potent antifungal activity in both in vitro and in vivo assays.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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