Aging does not alter cytosolic calcium levels of cortical synaptosomes in Fischer 344 rats

Several lines of experimental evidence support an association between altered Ca²⁺ regulation and aging. It has been supposed that free cytosolic Ca²⁺ concentrations ([Ca²⁺]_i) may decrease or increase in aged animals. In this study, both resting and KCl-stimulated [Ca²⁺]_i were measured in purified cortical synaptosomes from young (3 mo.), middle-aged (12 mo.), and old (24 mo.) Fischer 344 rats. Two additional groups of rats were included, one middle-aged and one old which were trained on a treadmill for 6 months prior to experimentation. The [Ca²⁺]_i was determined using the fluorescent Ca²⁺ chelator fura-2. Net KCl-dependent changes (ΔK) in [Ca²⁺]_i were determined by the difference between stimulatory (100 μM Ca²⁺/60 mM KCl) and resting (100 μM Ca²⁺/5 mM KCl buffer) conditions among the 3 age groups. Significant increases in [Ca²⁺]_i were observed in each age group upon depolarization with 60 mM KCl. However, there were no significant age-dependent differences in either resting [Ca²⁺]_i or KCl-stimulated [Ca²⁺]_i.     

Effect of Vero Cell Coculture on the Development of Frozen–Thawed Two-Cell Mouse Embryos

Purpose: Our purpose was to evaluate the beneficial effects of long-term coculture of Vero cells on the development of frozen–thawed two-cell mouse embryos. Methods: Two-cell mouse embryos were frozen slowly with 1,2-propandiol and sucrose as cryoprotectants and thawed rapidly, followed by stepwise dilution. Vero cells were cultured in drops of RPMI 1640 to establish monolayers. Frozen–thawed embryos were cultured alone (control) or cocultured with Vero cells. The rate of development in both groups was compared. Results: After 4 days of culture, significantly more embryos in coculture were developed to expanded blastocysts (61 vs 37% for controls; P 0.0001). In addition, on the fifth day of cultivation, more embryos in coculture showed the potential of hatching from the zona pellucida (26 vs 7% in controls; P 0.0001). The rate of degeneration in coculture was also much lower than in controls (6 and 15%, respectively). Conclusions: Coculture of cryopreserved preimplantation-stage embryos with Vero cells seems to be a useful tool to eliminate the postthaw deleterious effect of freezing and also to obtain better-quality embryos appropriate for transfer.     

Anxiogenic behavior in rats during acute and protracted ethanol withdrawal: reversal by buspirone.

This study investigated the effectiveness of buspirone in reversing the anxiogenic behaviors occurring during ethanol withdrawal as measured in the elevated plus-maze. In response to anxiogenic drugs, rats spend less time in and make fewer entries onto the open arms of an elevated plus-maze, whereas anxiolytic drugs produce opposite effects. In this study, rats were fed a liquid diet containing 4.5% ethanol for 7 days. Twelve h (acute withdrawal) and 7 days (protracted withdrawal) following cessation of the ethanol diet, rats were tested on the elevated plus-maze. During these withdrawal periods, the percent open-arm entries and time spent on the open arms were significantly reduced relative to animals fed an ethanol-free diet, suggestive of anxiogenic-like symptoms. Buspirone (0.32-1.25 mg/kg) dose dependently reversed the withdrawal-induced decreases in open-arm activity. The anxiolytic-like activity of buspirone observed during ethanol withdrawal may be due to a reduction in serotonergic neurotransmission through activation of presynaptic 5-HT1A autoreceptors. The results obtained in this study suggest that pharmacotherapy with selective 5-HT1A agonists may be beneficial in alleviation of anxiety during ethanol withdrawal.