def ek_R56Q(cell):
    """
    Returns the R56Q reversal potential (in mV) for the given integer index
    ``cell``.
    """
    reversal_potentials = {
        1: -96.0,
        2: -95.0,
        3: -90.5,
        4: -94.5,
        5: -94.5,
        6: -101.0
    }
    return reversal_potentials[cell]