[The generation of nonadrenergic inhibiting synaptic potentials in the smooth muscles of the gastrointestinal tract by substituting cesium ions for potassium ions].
Nonadrenergic inhibitory junction potentials (IJPs) evoked by intramural stimulation were investigated in smooth muscle of guinea pig stomach, caecum and colon by means of sucrose-gap method. IJPs disappeared in the smooth muscle preexposed to K-free Krebs solution for 4-9 h and restored by addition 6mM Cs+. The amplitude of IJPs was half as much as one in normal conditions but the latency and duration were significantly prolonged. In most cases apamin blocks IJPs in these muscles. The results presented suggest that IJPs generation is due to Cs+ ions permeated through Ca(2+)-activated apamin-sensitive potassium channels of small conductance in these conditions. As the responses to ATP were affected in parallel with IJPs, these results are consistent with the purinergic hypothesis.
Zagorodniuk
V P
VP
Vladimirova
I A
IA
Shuba
M F
MF
Hoyle
C
C
D000818:Animals; D002586:Cesium / Q000494:pharmacology*; D004064:Digestive System / Q000187:drug effects; D004068:Digestive System Physiological Phenomena; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007477:Ions; D007552:Isotonic Solutions; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009433:Neural Inhibition / Q000187:drug effects* / Q000502:physiology; D011188:Potassium / Q000494:pharmacology*; D011941:Receptors, Adrenergic / Q000502:physiology*; D013569:Synapses / Q000187:drug effects* / Q000502:physiology
D007477:Ions; D007552:Isotonic Solutions; C051865:Krebs-Ringer solution; D011941:Receptors, Adrenergic; D002586:Cesium; D011188:Potassium
Generatsiia neadrenergicheskikh tormoziashchikh sinapticheskikh potentsialov v gladkikh myshtsakh zheludochno-kishechnogo trakta pri zamene ionov kaliia ionami tseziia.