title: Effects of calmidazolium and dibutyryl cyclic AMP on the longitudinal internal resistance in sinus node strips.
abstract: The effects of calmidazolium (10(-7) mol/l) and db cAMP (10(-3) mol/l) on the longitudinal internal resistance (ri) in the rabbit sinus node strips were studied by means of microelectrode and extracellular recording techniques. Calmidazolium (CDZ) decreased ri by 27%. An addition of db cAMP to the CDZ-containing Tyrode potentiated this effect by further 14%. db cAMP initially decreased ri by 17%, then it enhanced this resistance by 7% above the pretreatment control value. An addition of CDZ to the db cAMP-containing Tyrode reduced ri by 41% below the pretreatment control. Possible mechanisms underlying these effects were discussed in terms of cAMP, Cai, and calmodulin action on the cell coupling.
authors.affiliation: Department of Physiology, Silesian School of Medicine, Katowice, Poland.
authors.forename: W
authors.initials: W
authors.lastname: Tuganowski
authors.forename: I
authors.initials: I
authors.lastname: Korczyńska
authors.forename: K
authors.initials: K
authors.lastname: Wasik
authors.forename: G
authors.initials: G
authors.lastname: Piatek
mesh_terms: D000818:Animals; D003994:Bucladesine / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects*; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D004553:Electric Conductivity; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D011817:Rabbits; D012849:Sinoatrial Node / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D007093:Imidazoles; C031938:calmidazolium; D003994:Bucladesine