Alpha-conotoxin ImI disrupts central control of swimming in the medicinal leech.
Medicinal leeches (Hirudo spp.) swim using a metachronal, front-to-back undulation. The behavior is generated by central pattern generators (CPGs) distributed along the animal's midbody ganglia and is coordinated by both central and peripheral mechanisms. Here we report that a component of the venom of Conus imperialis, α-conotoxin ImI, known to block nicotinic acetyl-choline receptors in other species, disrupts swimming. Leeches injected with the toxin swam in circles with exaggerated dorsoventral bends and reduced forward velocity. Fictive swimming in isolated nerve cords was even more strongly disrupted, indicating that the toxin targets the CPGs and central coordination, while peripheral coordination partially rescues the behavior in intact animals.
Wagenaar
Daniel A
DA
Broad Fellows Program and Division of Biology, California Institute of Technology, 1200 E California Blvd 216-76, Pasadena, CA 91125, USA. daw@caltech.edu
Gonzalez
Ruben
R
Ries
David C
DC
Kristan
William B
WB
French
Kathleen A
KA
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001696:Biomechanical Phenomena; D002490:Central Nervous System / Q000187:drug effects; D020916:Conotoxins / Q000494:pharmacology*; D055724:Electrophysiological Phenomena; D017952:Ganglia, Invertebrate / Q000502:physiology; D007865:Leeches / Q000502:physiology*; D009046:Motor Neurons / Q000187:drug effects; D018733:Nicotinic Antagonists / Q000494:pharmacology*; D017933:Peripheral Nervous System / Q000187:drug effects; D011597:Psychomotor Performance / Q000502:physiology; D011978:Receptors, Nicotinic / Q000187:drug effects*; D013550:Swimming / Q000502:physiology*
D020916:Conotoxins; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; C087686:alpha-conotoxin ImI