We have been experiencing an odd problem that appeared suddenly in our cortical whole-cell current clamp experiments. We use a potassium gluconate internal solution, standard ACSF at 32 Celsius with a flow rate of 2 mL per minute. 300 um cortical mouse brain slices. We experienced two problems:

1. Cells in our slices were shriveled and shredded. We attributed this to a vibratome issue, and sure enough saw healthy looking slices after using a different vibratome.

2. Cells have healthy break-in potentials (-60 to -70 mV resting), but spike widths of some cells are about double what they should be while other cells are only slightly increased. All cells also have much higher input resistances and lower rheobases than normal. This did not stop when we used a new vibratome for slicing.

We have:

- Used external and internal solutions prepared by a separate lab

- Replaced all tubing, recording chambers, wires, pipettes, and objectives on the rig

- Rechlorided all recording wires and grounds

- Checked pH and osmolarity to ensure they were in range

- Swapped out digidata and multiclamps

- Tried different mouselines across different ages

We assume there is some kind of contamination, as all hardware has been changed out and the problem still persisted. Has anyone experienced something similar or might have an idea of what could be causing these pervasive intrinsic changes across cell types?