title: On some presynaptic effects of meramyzole (analgine-pharmachim).
abstract: The effect of Analgine in different concentrations on the contractions of electrically stimulated isolated guinea-pig ileum and mouse vas deferens is studied and compared with the effect of morphine on the same isolated organs. Analgine causes morphine-like but weaker concentration-dependent inhibitory effect (IC50 = 5.75 X 10(-6) M) on guinea-pig ileum, which is completely eliminated by naloxon and 4-aminopyridine. Upon simultaneous administration of morphine analgine, potentiation of the effect of morphine is observed, which is also eliminated by naloxon and 4-aminopyridine. Analgine has a weaker inhibitory effect (IC50 = 1 X 10(-4) M) on the contractions of mouse vas deferens, compared with its effect on the ileum. The same is also valid for the independent and combined with analgine effect of morphine, completely eliminated only by 4-aminopyridine, but not by naloxon. In cases of reduced Na+-concentration in the medium, the effect of analgine on the contractions of the ileum is weaker (IC25 = 4.43 X 10(-5) M), while that of morphine is stronger compared with normal conditions. Increased Ca++-concentration is parallelled by a weaker effect of analgine (IC25 = 4.76 X 10(-5) M), unlike the effect of morphine which is potentiated. It is possible to assume some interaction of analgine with a definite type of presynaptic opiate receptors, similar or identical to these receptors which are responsible for the peripheral effects of the narcotic analgesics.
mesh_terms: D000632:Aminopyrine / Q000031:analogs & derivatives*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002118:Calcium / Q000502:physiology; D004177:Dipyrone / Q000031:analogs & derivatives* / Q000494:pharmacology; D004558:Electric Stimulation; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects / Q000294:innervation; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology; D047069:Pyrazolones; D012964:Sodium / Q000502:physiology; D013569:Synapses; D014649:Vas Deferens / Q000187:drug effects / Q000294:innervation
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D047069:Pyrazolones; D000632:Aminopyrine; D009270:Naloxone; D004177:Dipyrone; D012964:Sodium; C008667:noramidopyrine; D002118:Calcium