title: Impulses and pressure waves cause excitement and conduction in the nervous system.
abstract: It is general accepted, that nerval excitement and conduction is caused by voltage changes. However, the influx of fluid into an elastical tube releases impulses or pressure waves. Therefore an influx of ion currents, respectively fluid motions into the elastic neuronal cells and fibres also induce impulses. This motion of charge carriers are measured by voltage devices as oscillations or action potentials, but the voltage changes may be an epiphenomenon of the (mechanical) impulses. Impulse waves can have a high speed. As stiffer or inelastic a tube wall, the greater is the speed of the impulse. Myelin sheaths cause a significant stiffening of the nerve fibre wall and myelinated fibres have a conduction velocity up to 120 m/s. The influx of fluid at the nodes of Ranvier intensifies periodically the impulse wave in the nerve fibres. The authors suggest that also the muscle end-plate acts as a conductor of axonal impulses to the inner of the muscle fibres and that the exocytosis of acetylcholine into the synaptic cleft may be an amplifier of the axonal impulse. It is discussed that intracellular actin filaments may also influence motions at the neuronal membrane. Many sensory nerve cells are excited due to exogenous or endogenous mechanical impulses. It may plausible that such impulses are conducted directly to the sensory nerve cell bodies in the dorsal root ganglia without the transformation in electric energy. Excitation conduction happens without noteworthy energy consumption because the flow of ion currents through the membranes takes place equivalent to the concentration gradient. Impulse waves cause short extensions of the lipid membranes of the cell- and fibres walls and therefore they can induce opening and closing of the included ion channels. This mechanism acts to "voltage gated" and "ligand-gated" channels likewise. The concept of neuronal impulses can be helpful to the understanding of other points of neurophysiology or neuronal diseases. This includes e.g., the brain concussion and pathohistological findings in Alzheimer dementia. To verify the concept of (mechanical) impulses in the nervous system it is necessary to carry out biophysical or mechanical investigations in very small dimensions and the authors hope to give for this a sufficient stimulus.
authors: Holunderweg 17, D-18209 Bad Doberan, Germany; Neuropathology Department, Dietrich-Bonhoeffer Hospital, D-17022 Neubrandenburg, PF 400135 Mecklenburg-West Pomerania, Germany. Electronic address: HelmutBarz@gmx.de.
authors: Helmut
authors: H
authors: Barz
authors: Almut
authors: A
authors: Schreiber
authors: Ulrich
authors: U
authors: Barz
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena; D006801:Humans; D017136:Ion Transport / Q000502:physiology*; D008959:Models, Neurological; D009424:Nervous System Physiological Phenomena; D009482:Neurophysiology; D011312:Pressure