introduction: purkinje cell (pc) output displays a complex firing pattern consisting of high frequency sodium spikes and low frequency calcium spikes, and disruption in this firing behavior may contribute to cerebellar ataxia. riluzole, neuroprotective agent, has been demonstrated to have neuroprotective effects in cerebellar ataxia. here, the spectral analysis of pcs firing in control, 3-acety...

Experiments were performed on the lobster giant axon to determine the relation between intracellular spike amplitude and external calcium ion concentration. Action potential decline in low external calcium is greatly accelerated by simultaneous removal of external sodium ion. Correlation of the time course of spike decline in low calcium-low sodium solution with the time courses of spike declin...

Purkinje neurons can spike very rapidly for sustained periods. We examined the cycle of sodium channel gating during high-frequency firing of Purkinje neurons, focusing on the kinetics of sodium channel inactivation and recovery during and after spikes. To analyze sodium channel availability during spiking, we recorded the firing patterns of acutely dissociated Purkinje neurons in current clamp...

We measured the time course of sodium entry during action potentials of mouse central neurons at 37 degrees C to examine how efficiently sodium entry is coupled to depolarization. In cortical pyramidal neurons, sodium entry was nearly completely confined to the rising phase of the spike: only approximately 25% more sodium enters than the theoretical minimum necessary for spike depolarization. H...

Investigations concerning the ionic basis of the action potential in nerve and muscle have revealed a variety of mechanisms ranging from total dependence on sodium, first described quantitatively in the squid axon (Hodgkin & Huxley, 1952), to total dependence on calcium in crustacean muscles (Fatt & Ginsborg, 1958; Abbott & Parnas, 1965; Hagiwara & Naka, 1964; Hagiwara & Nakajima, 1966). Betwee...

Glutamatergic inputs from the subthalamic nucleus are suspected to provide a prominent source of excitation to globus pallidus (GP) neurons, despite their scarce number and mainly distal dendritic location. In this study we address the issue of whether dendritic sodium channels may facilitate the effect of excitatory inputs in GP. First, we examined the subcellular distribution of sodium channe...

Previous studies using pharmacological methods suggest that subthreshold sodium currents are critical for rhythmical burst generation in mesencephalic trigeminal neurons (Mes V). In this study, we characterized transient (I(NaT)), persistent (I(N)(aP)), and resurgent (I(res)) sodium currents in Na(v)1.6-null mice (med mouse, Na(v)1.6(-/-)) lacking expression of the sodium channel gene Scn8a. We...

to investigate the influence of salinity and calcium (ca) on some properties of plantago ovata, a pot factorialexperiment based on randomized complete block design with three replicates was conducted in jiroft, south of kermanprovince, iran. three salinity levels of 0, 100 and 200 mm nacl and ca levels of 0, 5 and 10 mm calcium nitrate wereapplied as the first and second factors, respectively. ...

To investigate the influence of salinity and calcium (Ca) on some properties of Plantago ovata, a pot factorialexperiment based on randomized complete block design with three replicates was conducted in Jiroft, south of KermanProvince, Iran. Three salinity levels of 0, 100 and 200 mM NaCl and Ca levels of 0, 5 and 10 mM Calcium nitrate wereapplied as the first and second factors, respectively. ...