title: Nitric oxide/cyclic guanosine monophosphate signaling in the central complex of the grasshopper brain inhibits singing behavior.
abstract: Grasshopper sound production, in the context of mate finding, courtship, and rivalry, is controlled by the central body complex in the protocerebrum. Stimulation of muscarinic acetylcholine receptors in the central complex has been demonstrated to stimulate specific singing in various grasshoppers including the species Chorthippus biguttulus. Sound production elicited by stimulation of muscarinic acetylcholine receptors in the central complex is inhibited by co-applications of various drugs activating the nitric oxide/cyclic guanosine monophosphate (cGMP) signaling pathway. The nitric oxide-donor sodium nitroprusside caused a reversible suppression of muscarine-stimulated sound production that could be blocked by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxaline-1-one (ODQ), which prevents the formation of cGMP by specifically inhibiting soluble guanylyl cyclase. Furthermore, injections of both the membrane-permeable cGMP analog 8-Br-cGMP and the specific inhibitor of the cGMP-degrading phosphodiesterase Zaprinast reversibly inhibited singing. To identify putative sources of nitric oxide, brains of Ch. biguttulus were subjected to both nitric oxide synthase immunocytochemistry and NADPH-diaphorase staining. Among other areas known to express nitric oxide synthase, both procedures consistently labeled peripheral layers in the upper division of the central body complex, suggesting that neurons supplying this neuropil contain nitric oxide synthase and may generate nitric oxide upon activation. Exposure of dissected brains to nitric oxide and 3-(5'hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) induced cGMP-associated immunoreactivity in both the upper and lower division. Therefore, both the morphological and pharmacological data presented in this study strongly suggest a contribution of the nitric oxide/cGMP signaling pathway to the central control of grasshopper sound production.
authors.affiliation: Institute of Zoology, University of Göttingen, 37073 Göttingen, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Wenzel
authors.forename: Michael
authors.initials: M
authors.lastname: Kunst
authors.forename: Cornelia
authors.initials: C
authors.lastname: Günther
authors.forename: Geoffrey K
authors.initials: GK
authors.lastname: Ganter
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lakes-Harlan
authors.forename: Norbert
authors.initials: N
authors.lastname: Elsner
authors.forename: Ralf
authors.initials: R
authors.lastname: Heinrich
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D006152:Cyclic GMP / Q000378:metabolism / Q000502:physiology*; D004347:Drug Interactions; D020536:Enzyme Activators / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007839:Functional Laterality / Q000187:drug effects; D006110:Grasshoppers; D007150:Immunohistochemistry / Q000379:methods; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D009116:Muscarine / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009569:Nitric Oxide / Q000502:physiology*; D009596:Nitrophenols / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D013997:Time Factors; D014828:Vocalization, Animal / Q000187:drug effects / Q000502:physiology*
chemical_list: D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D007191:Indazoles; D018721:Muscarinic Agonists; D009596:Nitrophenols; D009943:Organophosphorus Compounds; C090937:3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole; D009569:Nitric Oxide; C008644:nitrophenylphosphate; D009116:Muscarine; D006152:Cyclic GMP