Oscillations in the activity of a potassium channel at the presynaptic nerve terminal

Abstract

1. Periodic oscillations were detected in the activity of single macromolecules: potassium channels. 2. When potassium channels are repeatedly activated in isolated patches from fused synaptosomes of Torpedo electric organ, their behavior exhibits a departure from random activation. 3. The departure from random behavior is demonstrated by the runs test and by the lack of fit to Poisson distribution. 4. Under appropriate experimental conditions, the channels display periodic oscillations with a periodicity of approximately 20 s when activated at a rate of 1.25 Hz. 5. The oscillations do not arise from sampling, recording, or computational artifacts. 6. It is conceivable that single-channel oscillations play a role in the generation of membrane oscillations and thus may contribute to the oscillatory behavior of the nervous system.

Green Tea Catechins, (−)‐Catechin Gallate, and (−)‐Gallocatechin Gallate are Potent Inhibitors of ABA‐Induced Stomatal Closure

“…[ 61 , 62 ] Given that CG/GCG mainly affected Shaker ‐type ion channels, CNGC might be a possible target channel for CG/GCG binding in the ABA‐signaling pathway. In animal cells, K + channels are involved in the generation of membrane potential oscillation [ 63 , 64 , 65 ] and intracellular Ca 2+ oscillation. [ 66 ] Opening of K + channel, Kv1.3 elicits membrane depolarization, and then to opening of a Ca 2+ channel, IKCa1 causes cytosolic Ca 2+ elevation.…”

Single‐channel properties of BK‐type calcium‐activated potassium channels at a cholinergic presynaptic nerve terminal

“…Substantial evidence suggests that most, if not all, nerve terminals that secrete neurotransmitters by action potential‐dependent mechanisms exhibit a calcium‐activated potassium (K Ca ) channel. Such terminals include presynaptic nerve terminals at fast‐transmitting synapses (Bartschat & Blaustein, 1985; Farley & Rudy, 1988; Anderson et al 1988; Lindgren & Moore, 1989; Schneider et al 1989; Astrand & Stjarne, 1991; Sivaramakrishnan et al 1991; Robitaille & Charlton, 1992; Wangemann & Takeuchi, 1993; Blundon et al 1995; Rahamimoff et al 1995; Katz et al 1997; Sakaba et al 1997; Yazejian et al 1997), hormone‐secreting nerve terminals (Bielefeldt et al 1992; Wang & Lemos, 1992; Wang et al 1992; Bielefeldt & Jackson, 1993) and sense‐organ cells (such as hair cells, Edgington & Stewart, 1981; Roberts et al 1990, 1991; Issa & Hudspeth, 1994; Art et al 1995) which share many properties with fast‐transmitting nerve terminals. It is not clear which specific types of K Ca channel are present at most of these sites but, where tested by specific staining or direct recording, the high‐conductance, BK‐type has been repeatedly observed (Smith et al 1986; Castle & Strong, 1986; Roberts et al 1991; Robitaille & Charlton, 1992; Bielefeldt & Jackson, 1993; Wangemann & Takeuchi, 1993; Issa & Hudspeth, 1994; Art et al 1995; Knaus et al 1996).…”

Induction of pseudo‐periodic oscillation in voltage‐gated sodium channel properties is dependent on the duration of prolonged depolarization

“…However, this new property may not be restricted to IIA subtype of sodium channels. Time dependent oscillation in kinetic behaviour was observed earlier upon repetitive activation of single potassium channels when recorded from synaptosomes of Torpedo electric organ (Rahamimoff et al ., 1995). The role of voltage‐gated potassium channels in the subthreshold membrane potential oscillation have been documented also (Boehmer et al ., 2000).…”

“…However, nonlinearity in the prepulse potential dependence was observed in skeletal muscle µ1 sodium channel expressed in Xenopus oocyte (Hilber et al ., 2001). Previously, prepulse duration dependent oscillatory behaviour was observed at the single channel level of voltage‐gated potassium channel (Rahamimoff et al ., 1995).…”