Bautz C, Bohuslavizki KH, Hänsel W, Koppenhöfer E
Effects of Ruta on the Excitation Process in Myelinated Nerves: Abstracts 37thAnnual Congress on Medicinal Plant Research Braunschweig, 5.-9.09.1989
Planta Med. 1989: 2-14.
Single myelinated nerve Fibres of the toad Xenopus laevis were mounted in a recording chamber in such a fashion that the bathing fluid of the Ranvier node under investigation could be changed completely within a few seconds. Transmembraneous ionic currents of the nodal membrane were measured by means of the so-called potential clamp technique.
Ruta specimens from Germany and Spain were separated each into lots of lignified stipes, green stipes, leaves, seed-vessels, and seeds, respectively. Infusions were prepared with the normal bathing fluid (in mmol/l: NaCl 112.0. KCl 9.0, CaCl22.0. BESbuffer 5.0) according to the German Pharmacopeia No. 8. Care was taken that the concentrations of Na+, K+, and Ca2+ in the solutions used did not differ significantly from each other.
Ionic currents elicited by rectangular potential steps showed reversible depression of K+currents after application of each test solution within 30 s. Surprisingly, the kinetics of the remaining K+currents resembled those seen in the unmyelinated giant axon treated with long-chained triethylammonium compounds. Seed-vessels and leaves proved most efficacious in this connexion. No clear differences between corresponding lots from R. graveolens and R. chalepensis could be detected so far. It was also noted that Na+currents, which are essential for the spike genesis in the nerve, remained almost unaffected.
Electron microscopic studies suggested that MS leads to an uncovering of internodal K+channels located in the axonal membrane beneath the myelin sheath by demyelination of axons, thus rendering conduction of nerve spike very difficult. Therefore, blockage of pathophysiologically activated internodal K+-channels by some unknown specific blocker from Ruta might in fact improve nerve function in demyelinating diseases like MS.
Investigations into the Effectiveness of Ruta graveolens in Multiple Sclerosis [ Details ]