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  • 1970-1974  (6)
  • 1960-1964
  • Electron microscopy  (2)
  • Microvilli  (2)
  • Rats  (2)
  • Acquisition  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Ethanol as a reinforcer: Effects of fixed-ratio size and food deprivation (1973)
    Springer
    Psychopharmacology 28 (1973), S. 171-183 
    Details
    ISSN: 1432-2072
    Keywords: Ethanol Drinking ; Ethanol Reinforcement ; Fixed-Ratio Size ; Food Deprivation ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats having prior experience with ethanol drinking were subjected to geometrically increasing fixed-ratio (FR) schedules of ethanol reinforcement (8% W/V). The rats were tested first food deprived and then food satiated. Each third day ethanol was the reinforcer (0.25 ml/reinforcement), while on other days water, which served as the vehicle control, was available. Food satiating the rats decreased responding for ethanol whereas responding for water was not changed. Under both food conditions ethanol maintained responding at FR's up to 256 with response totals exceeding water control values. As the FR size increased to intermediate values, the number of ethanol responses increased. Further FR increases resulted in decreases in ethanol responding. The pattern of FR responding was similar to that maintained by other reinforcers. Maximum ethanol responding occurred at the beginning of the 6-h sessions, followed by a pause and then intermittent bursts of responding. Water responding was not characterized by a specific pattern. It was inferred that the odor of ethanol functioned as a discriminative stimulus, and it was concluded that ethanol served as a reinforcer for the rat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00421402
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Rapid establishment of ethanol as a reinforcer for rats (1974)
    Springer
    Psychopharmacology 37 (1974), S. 311-321 
    Details
    ISSN: 1432-2072
    Keywords: Rats ; Ethanol ; Ethanol Reinforcement ; Acquisition ; Schedule-Induced-Polydipsia ; Ethanol Concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Daily 6-h sessions were run during which each lever press by rats produced brief access to water, or to 8
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428917
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Patterns of morphogenesis mediated by dynamic microvilli: Chaetogenesis in Nereis vexillosa (1974)
    Springer
    Cell & tissue research 151 (1974), S. 141-157 
    Details
    ISSN: 1432-0878
    Keywords: Setae ; Polychaeta ; Microvilli ; Morphogenesis ; Chaetogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pattern of morphogenesis of the chitinous compound (jointed) setae of the larvae of polychaete Nereis vexillosa Grube was deduced from electron-microscopic analyses of many stages of secretion. Each seta is secreted over a period of three days within an epidermal follicle consisting of several lateral cells and a basal cell (chaetoblast). The configuration of the apical surface of the chaetoblast changes continuously during secretion. Secreted setal material is polymerized into longitudinally oriented setal filaments, probably by enzymes located on the surfaces of microvilli of the chaetoblast. As a result of this process the setae lengthen by basal appositional growth. We infer that the precise size and shape of each complex seta (a characteristic of the species and the age of the worm) is controlled by sequential modulations of the number, size, shape, arrangement and orientation of the microvilli of the chaetoblast. Each seta embodies a cryptic record of the activities of the chaetoblast on which it formed. The genetic and epigenetic mechanisms involved in chaetogenesis are problematic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222219
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  • 4
    Electronic Resource
    Electronic Resource
    Cephalopod integument: The ultrastructure of Kölliker's organs and their relationship to setae (1974)
    Springer
    Cell & tissue research 151 (1974), S. 293-308 
    Details
    ISSN: 1432-0878
    Keywords: Integument ; Octopus ; Setae ; Secretion ; Microvilli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Kölliker's tufts are transient epidermal bristles found on the external surfaces of late embryonic and juvenile octopods. The structure and growth of Kölliker's tuft is remarkably similar to that of polychaete setae. Each tuft is a fasicle of approximately 1500 distally tapered cannular rodlets located in an epidermal follicle composed of several lateral follicular cells and a single basal chaetoblast. The base of the follicle is associated with obliquely striated dermal muscle fibers. Together these elements comprise Kölliker's organ. The rodlets, composed of longitudinally oriented filaments, are separated basally from one another by a layered meshwork of interstitial filaments. Microvilli on the apical concave surface of the scyphate chaetoblast insert into the base of each rodlet. We infer that the tuft elongates by basal appositional growth and that glycoprotein secreted by the follicle cells is organized into filaments by the apical plasmalemma of the chaetoblast. Each microvillus serves as a template for the formation of a rodlet, therefore the number, size, shape, distribution and dynamic activity of the microvilli determine the morphology of the tuft.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224540
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  • 5
    Electronic Resource
    Electronic Resource
    Fine structure of the excretory system of Amphioxus (Branchiostoma floridae) and its response to osmotic stress (1974)
    Springer
    Cell & tissue research 148 (1974), S. 1-9 
    Details
    ISSN: 1432-0878
    Keywords: Branchiostoma ; Osmoregulation ; Cyrtocytes ; Podocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The excretory organs of Amphioxus occur as segmentally arranged structures throughout the pharyngeal region and may be divided into three components: the solenocytes, the renal tubule, and the renal glomerulus. The solenocytes possess foot processes that rest upon the coelomic surface of the ligamentum denticulatum. The tubular apparatus of the solenocytes consists of ten triangular rods surrounding a central flagellum. The distal end of the tubular apparatus enters branches of the renal tubule. The renal tubule eventually opens into the atrial cavity of Amphioxus. The renal glomerulus is a sinus within the connective tissue of the ligamentum dentieculatum where it connects elements of the branchial circulation with the dorsal aorta. The renal glomerulus, like other blood vessels of Amphioxus, lacks an endothelial lining. If Amphioxus is adapted to artificial sea water at different concentrations there is no change in kidney morphology suggesting that Amphioxus is either is osmotic with its environment or is osmoregulating with other organs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224314
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    The ascidian myocardium: Sarcoplasmic reticulum and excitation-contraction coupling (1972)
    Springer
    Cell & tissue research 129 (1972), S. 395-412 
    Details
    ISSN: 1432-0878
    Keywords: Cardiac muscle ; Sarcoplasmic reticulum ; Excitation-contraction coupling ; Electron microscopy ; Cinematography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ascidian myocardium is composed of small striated myoepithelial cells. The sarcoplasmic reticulum (SR) of these cells was reconstructed from serial sections. T-tubules are absent, but subsarcolemmal cisternae of the SR, that may be the counterpart of terminal cisternae, form couplings with the sarcolemma. Longitudinal SR tubules, parallel to the myofilaments, are interconnected near the middle of the A-band and form a transverse collar. Cinematographic photography of spontaneous contractions in fresh myocardial preparations produced records that could be analyzed frame by frame. Contractions are typically limited to parts of the myofilament field of single cells. They are locally symmetrical with respect to Z-bands; either both A-bands on each side of a Z-band converge on it (contractions), or neither A-band moves with respect to the Z-band. It is suggested that the spontaneous contractions are the result of local Ca++ release from randomly distributed subsarcolemmal cisternae. It is proposed that the symmetry of contraction is due to a rapid sequestering of Ca++ by the SR collars at the middle of the A-bands and a possible diffusion barrier at that level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307296
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    Paper (German National Licenses)
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