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  • Compound eye  (5)
  • Morphine  (5)
  • Aphids  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Asymmetrical effects of morphine and naloxone on reward mechanisms (1982)
    Springer
    Psychopharmacology 78 (1982), S. 219-224 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00428154
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  • 2
    Electronic Resource
    Electronic Resource
    Changes in morphine self-administration after tel-diencephalic lesions in rats (1978)
    Springer
    Psychopharmacology 57 (1978), S. 283-288 
    Details
    ISSN: 1432-2072
    Keywords: Morphine ; Self-administration ; Frontal cortex ; Posterior cortex ; Hippocampus ; Medial forebrain bundle ; Medial thalamus ; Nucleus accumbens ; Tuberculum olfactorium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were trained to bar-press for intravenous infusions of morphine sulfate during 1-h daily test sessions. Rates of moprhine self-administration were enhanced by lesions of the frontal cortex and hippocampus and transiently reduced by lesions of the medial forebrain bundle and medial thalamus. Doseresponse studies indicated that sensitivity to morphine's rewarding property was decreased by frontal cortical and hippocampal lesions. Lesions of the posterior cortex, the tuberculum olfactorium, and the nucleus accumbens had no effect on self-administration behavior. The results are discussed in relation to previous findings with caudate and brainstem lesions. A neuroanatomical substrate for morphine reinforcement is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00426752
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Morphine dependence in rats with medial forebrain bundle lesions (1973)
    Springer
    Psychopharmacology 30 (1973), S. 343-348 
    Details
    ISSN: 1432-2072
    Keywords: Morphine ; Withdrawal ; Addiction ; Dependence ; Medial Forebrain Bundle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats with posterior medial forebrain bundle (PMFB) lesions and control rats were administered morphine chronically for 4 or 5 days via implanted subcutaneous silicone reservoirs. Following cessation of morphine administration after five days, PMFB rats showed less withdrawal-induced weight loss than control rats. Other PMFB and control rats were subjected to forced drinking of morphine solution for 9 days. PMFB rats consumed the morphine solution much more readliy than control rats, whereas intake of a quinine solution was similar in two other PMFB and control groups. These results suggest that the addictive and dependence properties of morphine may have separate mechanisms and based on previously reported neurochemical effects of PMFB lesions, that biogenic amines may be differentially involved in such mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429193
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of morphine on sleep in the cat (1972)
    Springer
    Psychopharmacology 24 (1972), S. 435-448 
    Details
    ISSN: 1432-2072
    Keywords: Sleep ; Morphine ; Naloxone ; α-Methyltyrosine ; 5-Hydroxy-tryptophan.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of morphine sulfate, 300 μg/kg s.c., on the sleep of cats was studied by electroencephalographic techniques. In contrast to placebo experiments the animals were awake for approximately 6 h after administration of morphine; the return of regular sleep patterns occurred after about 11 h. A rebound increase in rapid eye movement (REM) sleep time and percentage was noted during the 11th through the 17th hour of the study. Sleep following manual sleep deprivation for 10 h showed a rebound increase in REM and non-rapid eye movement (NREM) sleep time. NREM sleep rebound after manual sleep deprivation exceeded that occurring after morphine. The alerting actions of morphine could be blocked by naloxone, 100 μg/kg s.c., for about 90 min. Naloxone alone increased REM sleep time and percentage. Single (84 mg/kg) or multiple (51 mg/kg for 4 injections) doses of dl-α-methyltyrosine i.p. did not block the alerting action or REM sleep rebound caused by morphine. 5-Hydrotryptophan (30 mg/kg) i.p. did not antagonize the alerting action of morphine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402538
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  • 5
    Electronic Resource
    Electronic Resource
    Changes in morphine self-administration after brainstem lesions in rats (1977)
    Springer
    Psychopharmacology 52 (1977), S. 151-156 
    Details
    ISSN: 1432-2072
    Keywords: Morphine ; Self-administration ; Substantia nigra ; Midbrain raphe nuclei ; Locus coeruleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were trained to bar press for intravenous infusions of morphine sulfate during 1-h daily test sessions. Rates of morphine self-administration were reduced by bilateral lesions of the substantia nigra and enhanced by lesions of the medial raphe nucleus. Dose-response studies indicated that sensitivity to morphine's rewarding property was increased by substantia nigra lesions and decreased by medial raphe lesions. Lesions of the dorsal raphe nucleus and of the locus coeruleus had no effect on self-administration behavior. An interaction between ascending dopaminergic and serotonergic pathways appears to be involved in the mechanism of morphine reinforcement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00439102
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  • 6
    Electronic Resource
    Electronic Resource
    Surface fine structure of the eye of the housefly (Musca domestica): Ommatidia and lamina ganglionaris (1974)
    Springer
    Cell & tissue research 149 (1974), S. 21-41 
    Details
    ISSN: 1432-0878
    Keywords: Compound eye ; Musca domestica ; Ommatidia ; Optic cartridge ; Basement membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The compound eye of the housefly, from lens to first optic neuropile (lamina ganglionaris) was examined with a scanning electron microscope. Key findings are as follows: The pseudocone cavity is enclosed by six corneal pigment cells. The nuclei of the six cells are firmly anchored to the underside of the lens and portions remain after lens delamination from the pseudocone cavity. An eccentrically-positioned, short photoreceptor cell was observed near the region where the inferior central cell initiates its rhabdom. This eminence may represent that cell's soma. The basement membrane is revealed as a two-tiered, fibrous layer with ovoid fenestrations. Each opening is sealed with a diaphragm perforated by eight retinular axons and a trachea. Conjoined distal surfaces of the satellite glial cells form a membrane-like barrier immediately underlying the basement membrane. Monopolar somata from the lamina are covered with glial cells which possibly make more intimate contact with the somata through miniscule projections. Optic cartridges with monopolar interneurons were noted. Spherical to slightly biconcave processes of these interneurons contact retinular axons. Very fine (1000 Å) filaments interweave among and contact lateral processes. Further implications are discussed as they relate to observed structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209048
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  • 7
    Electronic Resource
    Electronic Resource
    The large pigment cell of the compound eye of the house fly Musca domestica (1976)
    Springer
    Cell & tissue research 170 (1976), S. 77-88 
    Details
    ISSN: 1432-0878
    Keywords: Compound eye ; House fly ; Large pigment cells ; Corneal pigment cells ; High voltage and conventional electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure and cellular associations of the large pigment cells (LPC's) of the compound eye of the house fly were studied with high voltage and conventional electron microscopy. Depending on the sector of the compound eye, the facets are either rectangular or hexagonal. The underside of each facet has indentations exactly aligned with those on top into which inserts an angulated sleeve of LPC's. Under the rectangular lens facet 6 or 8 small compact (in cross section) LPC's join four elongate LPC's. Clusters of compact cells alternate in this ring with elongate ones. Compact cells compress together and become quadrangular (in cross section) several microns below their insertion into the lens and form “building block” corners while elongate cells form “side rails” for the rectangular type of distal pseudocone enclosure. Beneath hexagonal facets all LPC's are rather elongate with out corner cells. In both facet types LPC's enclose the pseudocone for a longitudinal distance of 4 μm and then are displaced as bordering cells by a sleeve of two corneal pigment cells (CPC's), each of which encloses half of the proximal pseudocone. For the following 6 μm of longitudinal distance these concentric sleeves of CPC's and LPC's form a double layer around the pseudocone. At about 10 μm below lens base the two sleeves separate; LPC's become attenuated and extend cable-like to the basement membrane and CPC's enclose the proximal pseudocone, Semper cells and distal retinula. The junction between lens and LPC's has critical structural value in that (1) this is the sole anchorage to the lens by the lengthy remainder of the ommatidium, and (2) LPC's enclose the semiliquid pseudocone in the most distal portion of the pseudocone. In addition to vertical support, the LPC's send out numerous lateral processes that make structural contact among themselves, with the corneal pigment cells and the photoreceptor cells. The structural features of this array are discussed relative to possible physiological roles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220111
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  • 8
    Electronic Resource
    Electronic Resource
    In vivo sterol biosynthesis by pea aphid symbiotes as determined by digitonin and electron microscopic autoradiography (1977)
    Springer
    Cell & tissue research 176 (1977), S. 179-190 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00229461
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of dietary cholesterol on the pattern of osmium deposition in the symbiote-containing cells of the pea aphid (1977)
    Springer
    Cell & tissue research 176 (1977), S. 191-203 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00229462
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  • 10
    Electronic Resource
    Electronic Resource
    The distal ommatidium of the compound eye of the housefly (Musca domestica): A scanning electron microscope study (1975)
    Springer
    Cell & tissue research 159 (1975), S. 379-385 
    Details
    ISSN: 1432-0878
    Keywords: Compound eye ; Musca domestica ; Ommatidium ; Distal retinula ; Scanning electron microscopy ; Corneal lens ; Corneal pigment cell ; Pseudocone ; Semper cell ; Basement membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distal aspect of the housefly ommatidium was surveyed by the scanning electron microscope. Attention was directed to the somal eminence of the superior central cell and the lens to large pigment cell junction. The underside of each lens facet exhibits six hexagonally arranged incisures. Into each of these indentations are fitted several large pigment cells. This hexagonal indentation appears to be a tenacious anchorage. Two corneal pigment cells laterally encircle the pseudocone and at their proximal extension they enclose the Semper cells and neck of the retinula. The somal eminence of the superior central cell is about 10 μm from the base of the corneal pigment cell enclosure. Micrographs were used to construct a diagram of the ommatidium above the basement membrane. Suggestions are made as to the functional correlates of the observed ommatidial structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221784
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