The role of protein phosphatases in regulating synaptic transmission in the CA1 region of the hippocampus was examined using slices pretreated with calyculin A, a specific inhibitor of protein phosphatases 1 and 2A. Stimulation of afferents at 1 Hz (but not 0.1 Hz) for periods of 5-10 min caused a long-lasting enhancement of synaptic transmission. The increase in synaptic responses was not due ...

The combination of automatic image acquisition and automatic image analysis of premature chromosome condensation (PCC) spreads was tested as a rapid biodosimeter protocol. Human peripheral lymphocytes were irradiated with (60)Co gamma rays in a single dose of between 1 and 20 Gy, stimulated with phytohaemaglutinin and incubated for 48 h, division blocked with Colcemid, and PCC-induced by Calycu...

Although the cGMP-dependent relaxation of contractile cells seems to depend on the ability of the cyclic nucleotide to interfere with intracellular calcium, this does not appear to be the only mechanism involved. The present experiments were designed to analyse alternative mechanisms, trying to test the hypothesis that cGMP could relax rat mesangial cells by activating myosin light-chain phosph...

The onset of constitutive cell death by apoptosis in human neutrophils can be delayed by treatment with glucocorticosteroids such as dexamethasone [ 1-31. The mechanisms underlying this steroid-mediated prolongation of neutrophil survival are however unknown. Okadaic acid and calyculin A, specific and potent inhibitors of protein phosphatases 1 and 2A, have been shown to influence the rate of a...

Previous research indicates that activation of protein kinase C (PKC) plays a critical role in the induction and maintenance of memory-related changes in neural excitability of Type B photoreceptors in the eyes of nudibranch mollusk Hermissenda crassicornis (H.c.). The enhanced excitability of B cells is due in part to PKC-mediated reduction in somatic K+ currents. Here we examined the effects ...