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  • 1
    ISSN: 1432-2072
    Keywords: Amphetamine ; Cocaine ; Conditioned avoidance response task ; Dizocilpine ; Haloperidol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A lever-release version of the conditioned avoidance response (CAR) task was used to assess the behavioral effects of several psychomotor stimulants in rats. The indirect dopamine agonists,d-amphetamine (0.1 and 0.25 mg/kg) and cocaine (7.5 and 15 mg/kg), enhanced performance on this task. Both drugs incre ased percent avoidance responses and decreased avoidance latency. A higher dose of amphetamine (0.5 mg/kg) also decreased avoidance latency but failed to improve percent avoidance. Similar effects were seen at low (0.01 and 0.025 mg/kg) and high (0.05 mg/kg) doses of dizocilpine (MK-801), a stimulant that acts as a noncompetitive antagonist ofN-methyl-d-aspartate (NMDA) glutamate receptors. When combined with haloperidol (0.1 mg/kg), a dopamine antagonist, amphetamine (0.25 mg/kg) and dizocilpine (0.025 mg/kg) had differential effects on the lever-release CAR task. Thus, amphetamine-haloperidol was significantly better than haloperidol alone on percent avoidance but not on avoidance latency, whereas dizocilpine-haloperidol had the opposite effect: significantly better than haloperidol alone on avoidance latency but not on percent avoidance. Taken together, these results provide further support for dopaminergic mechanisms in CAR performance but suggest an opposing glutamatergic influence.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 159 (1967), S. 273-279 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The activity of alkaline phosphatase, acid phosphatase, glutamic-oxalacetic transaminase (GOT), lactic dehydrogenase (LDH), amylase, succinic dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (GD) has been determined in the rabbit endometrium at estrus, in pseudopregnancy, and at days 5-10 of pregnancy. Enzyme analyses were also made on the placenta and embryo during early pregnancy.The most striking changes were increases in the SDH and GDH levels of the endometrium and a decrease in amylase when the does became pregnant or pseudopregnant. Amylase did not rise significantly from its lower level between five and ten days of pregnancy; SDH and GDH activity, however, fell away after reaching a maximum prior to implantation. At implantation there was some evidence of an increase in LDH and phosphatase activity. All enzymes had lower activities following implantation (10 days pregnancy). The endometrial enzyme activities of prepubertal does were usually similar to those of adult females in estrus. However, alkaline phosphatase activity of the prepubertal endometrium was particularly low.The activity of enzymes in the placental areas were, in general, similar to those found in the interplacental areas of the endometrium. However, from 7-10 days of pregnancy the activity of SDH was lower in the placental area than in the interplacental areas; whereas, amylase was higher on the eighth and ninth days of pregnancy. Changes in the activities of the phosphatases, GOT and SDH occurred in the blastocyst and trophoblast on eight to ten days of pregnancy. Enzyme activities in blastocoelic fluid were much less than in the trophoblast with the exception of amylase which was higher.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 354-360 
    ISSN: 1040-452X
    Keywords: Membrane potential ; Respiration ; Triton X-100 ; Fluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A simple procedure is described for determining the functional state of ram sperm mitochondria by quantitative measurement of sperm rhodamine 123 (R 123) accumulation. Sperm were incubated with 1 μg/ml R 123, and the accumulated R 123 was measured fluorimetrically after release from washed sperm by detergent lysis. Ram sperm R 123 uptake was maximal after 30 min of incubation and responded to changes in both sperm (P 〈 0.01) and R 123 (P 〈 0.01) concentration. There was a linear relationship (r = 0.98) between R 123 uptake and the proportion of cold-shocked sperm present in a sperm sample. R 123 uptake was unaffected by 20 mM 2-deoxyglucose or by 10 mM malonate (the latter being sufficient to reduce O2 uptake; P 〈 0.01). R 123 accumulation in ram sperm was reduced by 6 mg/ml sodium pentobarbitone (P 0.05), by 1 μM 2,4-dinitrophenol (P 〈 0.01), and by 0.05% Triton X-100 (P 〈 0.01). It is concluded that quantitative estimation of R 123 uptake complements oxygen uptake in detecting mitochondrial dysfunction in ram sperm. While it is largely unaffected by inhibition of glycolysis, and is less sensitive than oxygen uptake to trichloroacetic acid cycle inhibition, R 123 uptake is sensitive to factors directly reducing the mitochondrial membrane potential of ram sperm. It may therefore be useful in the evaluation of the effects of such membrane-mediated injuries as cold shock and freezing damage on ram sperm mitochondria. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 203-217 
    ISSN: 0148-7280
    Keywords: α-chlorohydrin ; antifertility agent ; ram ; sperm metabolism ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effects of the male antifertility agent, α-chlorohydrin, six of its derivatives, and glycidol were studied on the metabolism of washed ram spermatozoa in vitro with fructose as substrate. The α-chlorohydrin derivatives were the amino, the phosphorylated, and four glycol-bridge (ketal) compounds. All compounds except glycidol, in a concentration between 0.1 and 100 mM, reduced the aerobic glycolsis and/or oxidation of fructose. However, there was not a high correlation between the ability of these compounds to inhibit the metabolism of ram spermatozoa in vitro and their antifertility activity when administered to male rats. Other factors are clearly involved in their antifertility activity, eg, the concentration of the compounds in the epididymis and their conversion of either more or less spermicidal compounds in the body.
    Additional Material: 1 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 15 (1986), S. 43-56 
    ISSN: 0148-7280
    Keywords: calcium ; ultrastructure ; motility ; respiration ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rapid cooling (cold shocking) of washed ejaculated ram sperm to 0°C irreversibly reduced motility, tail beat frequency, and respiration and increased the uptake of 45Ca2+. The plasma membranes were removed from the sperm head, and the acrosomes were detached from the nuclei. The plasma membranes of the middle piece were removed, and the mitochondria contained pale and expanded cristae, similar in appearance to ATP-deprived mitochondria in the “condensed” configuration. The presence of 2.0 mg/ml phosphatidylcholine (lecithin) in the medium prevented ultrastructural damage on cold shock, and the motility, tail beat frequency, respiratory rate, and calcium uptake were maintained at levels similar to washed sperm. As the “protective” effect of phosphatidylcholine against cold shock was maintained to a certain extent after rewashing and centrifuging the sperm prior to cold shock, the interaction of phosphatidylcholine with ram sperm membranes may be fairly “tight” and not easily disrupted.
    Additional Material: 14 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 17 (1987), S. 355-373 
    ISSN: 0148-7280
    Keywords: motility ; respiration ; calcium ; ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rapidly cooling (cold shocking) washed cauda boar sperm irreversibly reduced motility and respiration and greatly increased the uptake of 45Ca2+; the plasma membranes were removed and the acrosomes detached from nuclei. The motility, respiration, and calcium uptake of the less mature caput sperm were largely unaffected; and there was little damage to the ultrastructure. This indicates that boar sperm becomes less resistant to cold shock as they mature in the epididymis.The oxygen uptake, glucose breakdown, and lactic acid production of control caput sperm was less than that of cauda sperm. This suggest that the maturation of sperm in the epididymis of the boar involves an increase in both the glycolytic and oxidative phases of glucose metabolism.The presence of 2.0 mg/ml phosphatidylcholine (lecithin) in the medium prevented ultrastructural damage to cauda sperm on cold shock, and motility and respiration were maintained at levels similar to those of control sperm. Although the presence of phospholipid reduced the large calcium influx following cold shock, it was still greater that that of control sperm.The “protective” effect against cold shock was not maintained after rewashing the sperm free of phosphatidylcholine prior to cold shock, indicating a fairly “loose” interaction of the phospholipid with boar sperm membranes that was easily disrupted.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 15 (1986), S. 361-371 
    ISSN: 0148-7280
    Keywords: extraction ; ATP ; partial demembranation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: For optimal extraction and reactivation of ram sperm, glutamate, dithiothreitol, magnesium, and cyclic AMP were required in a medium of pH 7.9. On extraction with 0.01 % Triton X-100, ram sperm were only partially demembranated, and extensive areas of plasma membrane remained intact especially in the midpiece region. Treatment with 0.1% Triton X-100 removed all plasma membranes and extracted the mitochondrial membrane and matrix. In the absence of ATP, 16.6% ± 0.4 of the partially demembranated sperm were motile, but sperm extracted with 0.1% Triton X-100 were completely immotile. On adding ATP partially demembranated sperm reactivated better (81.6% ± 2.8) than sperm completely demembranated in 0.1 % Triton X-100 (39.5% ± 4.6). The release of intracellular LDH rose linearly with increasing concentrations of the detergent from 0.01 to 0.05%, at which it plateaued. There was a significant increase in beat frequency and forward velocity of partially demembranated sperm when treated with ATP. Partially demembranated sperm had intact mitochondria that presumably were still able to produce ATP, although the spermatozoan movement was stimulated by exogenous ATP.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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