Material from the internal surface of squid axon exhibits excess noise. Implications in modeling membrane noise.
A fluid material from a squid (Loligo pealei) axon was isolated by mechanical application of two types of microcapillary (1-3-mum Diam) to the internal surface of intact and cut-axon preparations. Current noise in the isolated material exceeded thermal levels and power spectra were 1/f in form in the frequency range 1.25-500 Hz with voltage-dependent intensities that were unrelated to specific ion channels. Whether conduction in this material is a significant source of excess noise during axon conduction remains to be determined. Nevertheless, a source of excess noise external to or within an ion channel may not be properly represented solely as an additive term to the spectrum of ion channel noise; a deconvolution of these spectral components may be required for modeling purposes.
D000818:Animals; D001369:Axons / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D049832:Decapodiformes / Q000502:physiology*; D007473:Ion Channels / Q000502:physiology; D008954:Models, Biological; D009622:Noise
D007473:Ion Channels