title: Nitric oxide modulates local reflexes of the tailfan of the crayfish.
abstract: Electrical stimulation of sensory neurons that innervate receptors on the tailfan of crayfish evokes a reflex response of motor neurons that produce movements of the blades of the tailfan, the uropods. We analyzed the modulatory effects of nitric oxide (NO) on the spike frequency of the reflex response. Bath application of L-arginine and SNAP, which elevate endogenous and exogenous NO levels, increased the frequency of the evoked response, whereas the application of L-NAME and PTIO, which reduce NO levels, decreased the frequency of the response. To determine through what pathway and target NO exerted these effects we bath applied ODQ, an inhibitor of soluble guanylyl cyclase (sGC), which decreased the frequency of response, and 8-br-cGMP, which increased the spike frequency of response. To provide further evidence that NO acts via sGC, we elevated NO levels with L-arginine while simultaneously inhibiting sGC with ODQ. This application reduced the response to control levels, indicating that NO in the terminal ganglion of crayfish acts via sGC to modulate cGMP levels, which in turn regulate the responses of the uropod motor neurons.
authors.affiliation: School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, Southampton SO16 7PX, United Kingdom.
authors.forename: Makoto
authors.initials: M
authors.lastname: Araki
authors.forename: Hansjürgen
authors.initials: H
authors.lastname: Schuppe
authors.forename: Sawako
authors.initials: S
authors.lastname: Fujimoto
authors.forename: Toshiki
authors.initials: T
authors.lastname: Nagayama
authors.forename: Philip L
authors.initials: PL
authors.lastname: Newland
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D003400:Astacoidea; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D003497:Cyclic N-Oxides / Q000494:pharmacology; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010847:Picolines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D012018:Reflex / Q000187:drug effects / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D003497:Cyclic N-Oxides; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D007093:Imidazoles; D020030:Nitric Oxide Donors; D010069:Oxadiazoles; D010847:Picolines; D011810:Quinoxalines; C110881:S-nitro-N-acetylpenicillamine; D013873:Thionucleotides; C083763:8-bromoguanosino-3',5'-cyclic monophosphorothioate; C079391:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; D009569:Nitric Oxide; C058388:penclomedine; D001120:Arginine; D010396:Penicillamine; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester