Effects of tetraethylammonium-chloride and divalent cations on the afterhyperpolarization following repetitive firing in leech neurons.
In leech Retzius cells, repetitive activity evoked a prolonged Ca2+-dependent after-hyperpolarization (PAH) (30-60 s) accompanied by an increase in input conductance. PAH persisted in Retzius cells, as well as in nociceptive (N) cells, when Sr2+ but not Mg2+ was substituted for Ca2+. In the presence of tetraethylammonium-chloride (TEA) or Ba2+, PAH was replaced by a Ca2+-dependent, Mg2+-blockable depolarization which was present in the order N greater than R. Careful study of the differences in such phenomena in identified cells may improve our understanding of the differential susceptibility of various neurons to hyperexcitability.
D000818:Animals; D001464:Barium / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D007865:Leeches; D008274:Magnesium / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology*
D002413:Cations, Divalent; D013757:Tetraethylammonium Compounds; D001464:Barium; D019789:Tetraethylammonium; D008274:Magnesium; D002118:Calcium