Mumps Virus-induced Alterations in Cellular Excitability During Persistent Infections

Loss of Functional Voltage-gated Sodium Channels in Persistent Mumps Virus-infected PC12 Cells

“…These normal SEAPs were well developed and had relatively (i) large amplitudes, (ii) rapid rates of rise, (iii) brief durations, (iv) deep after-hyperpolarizations (AHPs) and (v) small subthreshold oscillations of the membrane potential superimposed on the electrotronic profile which followed the SEAP. This SEAP profile is identical to those seen in previous studies of normal PC12 cells (Dichter et al, 1977;O'Lague & Huttner, 1980;Rudy et al, 1982;Ziegler & Stauffer, 1987). The responsiveness illustrated in Fig.…”

“…Resting membrane potentials ranged from -3 1 to -57 mV. In order to facilitate activation of action potential electrogenic mechanisms, cells were held at -8 0 to -1 0 0 mV prior to stimulation (Dichter et al, 1977;Ziegler & Stauffer, 1987). We also found that PC12 cells would sometimes respond to relatively brief (1 to 5 ms) stimulus pulses.…”

“…MV-infected (MVI) cultures were found to have a greater proportion of cells that generated stimulus-evoked action potentials (SEAPs) which were smaller in magnitude, had slower depolarization rise times, and were longer in duration than those recorded from mock-infected (MI) control cultures (Ziegler & Stauffer, 1987). These findings were consistent with an altered phase of depolarization and, as such, it was hypothesized that MV might be interfering with the voltage-gated Na ÷ channels which are known to contribute to SEAP electrogenesis in the two cell lines (Dichter et al, 1977;O'Lague & Huttner, 1980;Syapin et al, 1982).…”

“…To determine whether MV could also affect membrane-related functions in persistently infected cell lines, we developed persistent infections of human medulloblastoma (TE671) and rat pheochromocytoma (PC12) cells (Ziegler & Stauffer, 1987). MV-infected (MVI) cultures were found to have a greater proportion of cells that generated stimulus-evoked action potentials (SEAPs) which were smaller in magnitude, had slower depolarization rise times, and were longer in duration than those recorded from mock-infected (MI) control cultures (Ziegler & Stauffer, 1987).…”

“…Cultures of MI and persistent MVI PC 12 cells were prepared and maintained in tissue culture flasks as previously described (Ziegler & Stauffer, 1987). Electrophysiological studies were performed on cultures containing 10 s MI or MVI cells, which had been added to collagen-coated 35 mm tissue culture plates and grown in Dulbecco's modified Eagle's medium with 10 9/0 foetal Short communication bovine serum, 5 % heat-inactivated horse serum, 20 mg/ml of gentamicin, and 20 gg/ml of mouse 7s nerve growth factor (NGF) for 17 days.…”