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  • 1
    ISSN: 1432-1106
    Keywords: Key words Protein lateral mobility ; Plasma membrane of brain cells ; Fluorescence recovery after photobleaching ; Concanavalin-A-receptors ; Concanavalin-A-fluorescein conjugate ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A new method has been developed for ex vivo preparation of brain cortical cells of BN/BiRijHsd rats to make them suitable for the measurement of the lateral diffusion coefficient of the membrane components by means of fluorescence recovery after photobleaching (FRAP). The method involves chopping the brain cortex into pieces of less than 1 mm. These parts are stained with a fluorescent label (e.g., concanavalin-A-fluorescein, Con-A-FL conjugate) and then gently pressed onto a microscope slide using the coverslip. In the resulting specimen, the largest cells of the cortex can be recognized in phase-contrast image, sufficiently stained by the label and ready for the FRAP measurement. The lateral diffusion coefficient of Con-A-receptor proteins (D p) was measured in such brain cell preparations of 15 female rats in four age groups (5.6–31.8 months) and 11 males in three age groups (13.8–31.8 months). Highly significant negative, linear age correlation of D p (R=−0.9958 in females, and −0.9956 in males) were found, the regression equations being D p,=(8.8311–0.1425 X)−10 and D p█=(9.3240−0.1630 X)−10 cm2/s, respectively, where X is age in months. The data confirm that the lateral mobility of plasma membrane proteins represents an important biomarker of cellular aging in the brain cortical cells of BN/BiRijHsd rats.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-2568
    Keywords: bile ; pancreatic secretion ; CCK
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Pancreatic exocrine secretion in conscious rats is regulated by intraluminal bile and/or pancreatic juice. Exclusion of bile and/or pancreatic juice from the intestinal lumen caused cholecystokinin (CCK) release and stimulated pancreatic secretion. CCK in the plasma is mainly derived from endocrine cells in the proximal small intestinal mucosa. We examined the changes in CCK concentrations in the intestinal mucosa and compared them to those of plasma CCK concentrations and the changes of luminal trypsin activities after bile and/or pancreatic juice diversion in conscious rats. Rats with bile and pancreatic fistulae were used. Each treatment of bile, pancreatic juice, and bile-pancreatic juice diversion decreased luminal trypsin activity and increased plasma and intestinal CCK concentrations. The potency of the stimulatory effect on plasma and intestinal CCK concentrations was bilepancreatic juice diversion〉pancreatic juice diversion≧bile diversion. Neither plasma CCK concentration nor intestinal CCK concentration was in inverse proportion to trypsin activity. The plasma CCK concentration did not parallel intestinal CCK concentration. Intravenous infusion of CCK-8 (300 pmol/kg/hr) did not increase CCK concentration in the intestinal mucosa. It was proposed that bile and/or pancreatic juice in the intestinal lumen regulated CCK concentrations not only in the plasma but also in the intestinal mucosa.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 34 (1989), S. 841-848 
    ISSN: 1573-2568
    Keywords: rat pancreas ; aging ; exocrine function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Basal pancreatic exocrine functions as well as responses to endogenous (BPJ diversion) and exogenous (injection of CCK-8 or secretin) stimulations were examined in young (6- and 12-month-old) and old (24- to 26-month old) female Fischer 344 rats. Basal secretions were not significantly different between young and old rats. BPJ diversion significantly stimulated pancreatic secretions of fluid, bicarbonate, and protein in all animals. The pancreatic protein response (mg/kg/hr) to BPJ diversion was significantly attenuated with respect to age [57.59±16.16, 43.73±6.94, and 20.75±3.95, for 6-, 12-, 24- to 26- month-old rats, respectively, mean ±se, F(2,20)=3.49, P 〈 0.05]. The pancreatic responses to secretin (0.086, 0.432, and 1.728 nmol/kg) were not significantly different between young and old rats. Intravenous injection of CCK-8 (0.033, 0.167, and 0.667 nmol/kg) produced a significant increase in protein output in all age groups. In young animals, stepwise increases in protein output were observed, whereas, in old rats, increments in response to the larger two doses of CCK-8 (0.167 and 0.667 nmol) were smaller than that produced by 0.033 nmol/kg of CCK-8. In conclusion, the basal secretions in old rats were comparable with those in young ones, but the reserve capacity for protein secretion appears to decrease in old compared to young rats.
    Type of Medium: Electronic Resource
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