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    Distinct functions of down‐regulation‐sensitive and ‐resistant types of protein kinase C in rabbit aortic smooth muscle cells
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    Abstract:
    In quiescent cultures of rabbit aortic smooth muscle cells, 12-O-tetradecanoylphorbol-13-acetate (TPA) induced DNA synthesis to some extent in the presence of rabbit plasma-derived serum but inhibited the rabbit whole blood serum (WBS)-induced DNA synthesis and increase in cytoplasmic free Ca2+ concentration Ca2+]i). Prolonged treatment of the cells with phorbol-12,13-dibutyrate (PDBu) caused the partial down-regulation of protein kinase C to a level of 25-35% of that in control cells. In these PDBu-pretreated cells, TPA neither induced DNA synthesis nor inhibited the WBS-induced DNA synthesis, but still inhibited the WBS-induced increase in [Ca2+]i. These results suggest that there are down-regulation-sensitive and -resistant types of protein kinase C in rabbit aortic smooth muscle cells; that the down-regulation-sensitive type has the proliferative and antiproliferative actions whereas the down-regulation-resistant type lacks them; and that the down-regulation-resistant type has the activity to inhibit the WBS-induced increase in [Ca2+]i.
    Keywords:
    Rabbit (cipher)
    cGMP-dependent protein kinase
    Lagomorpha
    ABSTRACT The aim of the study was to determine whether rabbit eggs’attract’ homologous spermatozoa in vivo. Preliminary experiments showed that, in vitro, rabbit spermatozoa readily and irreversibly attach to the zonae of rat eggs. When rat and rabbit eggs were transferred into oviducts of previously mated rabbits, a significantly larger number of spermatozoa collected within the rabbit eggs than on the zonae of the rat eggs. Since the experiments were designed so that rat and rabbit eggs had equal chances of sustaining collisions with rabbit spermatozoa, the great preponderance of spermatozoa in the rabbit eggs suggests that the latter exert a chemotactic influence on rabbit spermatozoa.
    Rabbit (cipher)
    Lagomorpha
    Citations (30)
    The aim of this study was to prepare and test an artificial corneal epithelium (reconstituted rabbit corneal epithelium, RRCE) exhibiting barrier characteristics and paracellular permeability similar to those of native rabbit cornea. The RRCE was obtained from a rabbit corneal epithelium (RCE) cell line grown for 8 days in submerged culture, then for 7 days in airinterface conditions on Snapwell® polyester membranes. Permeation studies on the RRCE were carried out in comparison with rabbit excised corneas in vitro, using timolol maleate (TM) as the test drug, alone and in association with the following ocular permeation enhancers: benzalkonium chloride, ethylene-diaminetetraacetic acid sodium salt, polyethoxylated castor oil, polyoxyethylene stearyl ether, sodium deoxycholate, and escin. The integrity of the RRCE was assessed by measuring the transepithelial electrical resistance (TEER) during culture time and after every permeation experiment. When TM was tested alone, the permeation parameters (apparent permeability coefficient, lag time) obtained with the RRCE were similar to those of excised rabbit corneas. The artificial epithelium, however, was less sensitive than native cornea to the effect of permeation enhancers.
    Rabbit (cipher)
    Lagomorpha
    Citations (1)
    We examined the behavior of rabbit factor XI (rabbit F. XI) in Watanabe-hereditable hyperlipidemic rabbit (WHHL rabbit), to study the participation of F. XI in atherosclerosis. Rabbit F. XI was isolated with use of anti-human F. XI monoclonal antibody-Sepharose. Purified rabbit F. XI was single band in sodium dodecylsulfate polyacrylamide gel electrophoresis (M. W.: 80, 000), and the specific coagulant activity was 75unit/mg protein. 125I-rabbit F. XI, iodinated with Bolton-Hunter reagent, was administered intravenously to WHHL rabbit and Japanese white rabbit (normal). Then blood was taken from ear vein and the trichloroacetic acid precipitate of plasma was counted. Turnover of 125I-rabbit F. XI was significantly faster in WHHL rabbit (T1/2=2.84±0.44 days) than in normal (T1/2=4.44±0.42 days). By en-face autoradiography, specific accumulation of 125I-rabbit F. XI was observed in thoracic aorta of WHHL rabbit. In contrast, no radioactivity was observed in normal. These results suggest that activation of F. XI proceeds on the atherosclerotic lesion of WHHL rabbit.
    Rabbit (cipher)
    Lagomorpha
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