Membrane potentials in an acanthocephalan worm (macracanthorhynchus hirudinaceus).
The resting membrane potential of the acanthocephalan rete system in Macracanthorhynchus hirudinaceus was -35 +/- 1.5 mV (n = 20) and was dependent upon the external potassium concentration. The membrane potential reached 0 mV when the external potassium concentration was 160 mM. Spontaneous spike potentials of 45 mV +/- 10 were dependent on calcium flux. The membrane potential was depolarized by acetylcholine, potassium-free medium, calcium ions and chloride-free medium but not by changes in the external sodium concentration. Spontaneous potentials were increased in number by acetylcholine and calcium at concentrations above 3 mM, but were decreased in number by chloride- and calcium-free medium. Hence the rete system potentials are very similar to smooth muscle potentials in many respects.
D000049:Acanthocephala / Q000502:physiology*; D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D007811:Lanthanum / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009130:Muscle, Smooth / Q000502:physiology; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology
D007811:Lanthanum; D012964:Sodium; D002122:Calcium Chloride; D000109:Acetylcholine; D011188:Potassium