Functioning of K channels during sleep

The functioning of voltage‐dependent K channels (Kv) may correlate with the physiological state of brain in organisms, including the sleep in Drosophila. Apparently, all major types of K currents are expressed in CNS of this model organism. These are the Shab—Kv2, Shaker—Kv1, Shal—Kv4, and Shaw—Kv3 α subunits and can be deciphered by patch‐clamp technique. Although it is plausible that some of these channels may play a prevailing role in sleep or wakefulness, several of recent data are not conclusive. It needs to be defined that indeed the frequency of action potentials in large ventral lateral pacemaker neurons is either higher or lower during the morning or night because of an increased Kv3 and Kv4 currents, respectively. The outcomes of dynamic‐clamp approach in combination with electrophysiology in insects are unreliable in contrast to those in mammalian neurons. Since the addition of virtual Kv conductance during any Zeitgeber time should not significantly alter the resting membrane potential. This review explains the Drosophila sleep behavior based on neural activity with respect to K current‐driven action potential rate. Spontaneous spikes in large LNV neurons. (A) Frequency during morning before and after a virtual Kv4 − Shal conductance. The spontaneous depolarization ★ is not related to dynamic‐clamp currents. Dashed boxes reflect changes in spike amplitude. Note a strong depolarization and comparable to baseline rate of spikes at the end of patch‐clamp trace. (B) Current behavior in the same neuron in response to applied conductance. Arrows point whether the MP and spikes or currents are drivers. (C) Response of neuron to virtual Kv3 − Shaw conductance. (D) Behavior of currents before and during dynamic‐clamp.