One of the main challenges for a better understanding of signaling mechanisms in the normal and diseased central nervous system (CNS) is to unravel the molecular basics of function on the cellular and systemic levels. Several important cellular processes, such as proliferation, differentiation, and cell death, are directly or indirectly influenced or even controlled by the activity of ion channels and receptors. The patch-clamp technique has been proven a powerful method for studying functional peculiarities of such channels, which considerably improved our knowledge of mechanisms underlying neuronal excitation and inhibition.