Abstract The hippocampal mossy fiber synapse is a key of the trisynaptic circuit. Post-tetanic potentiation (PTP) most powerful form plasticity at this synaptic connection. It widely believed that PTP an entirely presynaptic phenomenon, implying induction input-specific, and requires neither activity multiple inputs nor stimulation postsynaptic neurons. To directly test cooperativity associativ...

1. The effect of rabbit anti-(pigeon erythrocyte) antibodies plus human complement on the concentration of intracellular free Ca2+ in sealed pigeon erythrocyte 'ghosts' was investigated with the photoprotein obelin. 2. The addition of human serum, as a source of complement, to 'ghosts' coated with antibody caused a rapid increase in intracellular free Ca2+ after a lag of 20-40 s, as detected by...

Plasma gelsolin formed a very tight 1:2 complex with G-actin in the presence of Ca2+, but no interaction between gelsolin and G-actin was detected in the presence of excess EGTA. However, the 1:2 complex dissociated into a 1:1 gelsolin:actin complex and monomeric actin when excess EGTA was added. Plasma gelsolin bound tightly to the barbed ends of actin filaments and also severed filaments in t...

Barrier tissue protects the body against external factors by restricting the passage of molecules. The gastrointestinal epithelium is an example of barrier tissue with the primary purpose of allowing the passage of ions and nutrients, while restricting the passage of pathogens and toxins. It is well known that the loss of barrier function can be instigated by a decrease in extracellular calcium...

Synthetic myosin thick filaments were formed from preparations of electrophoretically homogeneous myosin isolated from Chaos carolinensis and Amoeba proteus when dialysed to physiological ionic strength and pH. Myosin dialysed directly against low ionic strength buffers formed native-like thick filaments in the presence and absence of exogenous divalent cations. The average dimensions of the sy...

prolonged incubation. HuO lytic titers were typically lower than those for Rb in the same sera.In 91 commercial drakes complete HuO lysis occurred in 14/91 (15%), ≥ 50% lysis in 51/91 (56%), but 7 (8%) sera were negative. Heating sera reduced lytic capacity for both HuO and Rb but not to the same degree. Nearly all HuO lytic capacity was removed after 10 min exposure to 57°C while the same trea...

Single pressure injections of 1-10 pl of inositol 1,4,5 triphosphate (IP3) or inositol 4,5 bisphosphate [I(4,5)P2] excite Limulus ventral photoreceptors by inducing rapid bursts of inward current. After excitation by IP3, responses to subsequent injections of IP3 or light flashes are often reversibly diminished (adapted). Single injections of IP3 and I(4,5)P2 are effective at concentrations in ...

Changes at the mitochondria are an early, required step in apoptosis in various cell types. We used western blot analysis to demonstrate that the proapoptotic protein Bax translocated from the cytosolic to the mitochondrial fraction in SH-SY5Y human neuroblastoma cells undergoing staurosporineor EGTA-mediated apoptosis. Levels of mitochondrial Bax increased 15 min after staurosporine treatment....

Changes at the mitochondria are an early, required step in apoptosis in various cell types. We used western blot analysis to demonstrate that the proapoptotic protein Bax translocated from the cytosolic to the mitochondrial fraction in SH-SY5Y human neuroblastoma cells undergoing staurosporine- or EGTA-mediated apoptosis. Levels of mitochondrial Bax increased 15 min after staurosporine treatmen...

The effects of removing external calcium and inhibiting entry of calcium into the cell by treatment with D-600 on renin release from renal cortical slices of male Sprague-Dawley rats were examined. Baseline renin release, angiotensin II (AII)-induced inhibition, and isoproterenol-induced stimulation of renin release were studied. Removal of external calcium by chelation with 5 mM EGTA inhibited...