title: Effects of exposure to high potassium concentration on the longitudinal muscle-myenteric plexus preparation from guinea-pig.
abstract: The effect of potassium on the longitudinal muscle-myenteric plexus (LM-MP) preparation from guinea-pig was studied. The strips were exposed to elevated K+ (30 mM, 60 mM, 90 mM, 120 mM or 150 mM). A phasic contraction of the LM-MP was caused by 10 mM K+ or 15 mM K+ followed by an increase of the contractile activity probably due to the increase in acetylcholine release. A higher molarity of K+ produces more marked depolarization in the LM-MP and above 22 mM K+ tetanizing effects were observed. We attempted to demonstrate that opiate-like material could be released when the tissue was exposed to more than 30 mM K+ even though several different neurotransmitters could be liberated by elevated K+ molarities.
mesh_terms: D000818:Animals; D004576:Electromyography; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000294:innervation / Q000378:metabolism; D009197:Myenteric Plexus / Q000187:drug effects* / Q000502:physiology; D009433:Neural Inhibition / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology*
chemical_list: D011188:Potassium